* These Memorial Articles were read at a meeting of the New
England Meteorological Society, October, 1891.
I.
FERREL'S EARLY ASTRONOMICAL WORK
BY PROFESSOR SIMON NEWCOMB
Superintendent Nautical Almanac.
It is remarkable
that among Ferrel's earliest published papers is one that should
have made an epoch in the progress of Astronomical Physics.
He was the first person to show from correct theory, that the
action of the moon in causing the tides should produce a retardation
of the earth's rotation. The paper in which this conclusion
was reached appeared in Volume 3 of Gould's Astronomical
Journal in 1853.
It is remarkable
that among Ferrel's earliest published papers is one that should
have made an epoch in the progress of Astronomical Physics.
He was the first person to show from correct theory, that the
action of the moon in causing the tides should produce a retardation
of the earth's rotation. The paper in which this conclusion
was reached appeared in Volume 3 of Gould's Astronomical
Journal in 1853.
The conclusion
that such a retardation would be produced was indeed drawn by
Kant, more than a century ago, in an essay which gained a prize
from the Berlin Academy of Sciences, but dynamical laws were
not well understood at that time, and Kant's conclusion was
founded on the idea that the tide- producing force of the moon
produced an actual motion of the ocean toward the west. Laplace
reached an opposite conclusion, which, so far as I know, was
undisputed until Ferrel wrote. He pointed out that Laplace's
conclusion was reached by neglecting certain effects of the
second order, and that when these were taken into account a
retardation would be produced. His numerical computation was,
however, to a great extent hypothetical. Assuming that the tide
caused by the moon in the open sea is two feet in height, and
that it is highest two hours after the moon passes the meridian,
he finds that if the ocean covered the earth, the equatorial
retardation of the latter would amount to fifty miles in a century.
Deducting one-fourth for the land surface, and adding the effect
of the sun, the result would be reduced to forty-four miles.
If the earth were really retarded by this amount, an apparent
acceleration in the motion of the moon amounting to 84" in a
century, would be produced. As no such acceleration was observed,
except what was otherwise accounted for, he concluded that the
retarding affect of the sun and moon must be nearly balanced
through the gradual contraction of the earth by loss of temperature;
a conclusion which is now known to be not well founded.
Up to this
time it was supposed that the theoretical value of the secular
acceleration as computed by Laplace, was exactly equal to the
observed value, and therefore that no retardation really existed.
But when, about 1860, it was well established that Laplace's
result was incorrect, a discrepancy between these two quantities
was the result. Ferrel then returned to the subject in a paper
on The Influence of the Tides in Causing an Apparent Secular
Acceleration of the Moon's Mean Motion, which was read before
the American Academy at Boston, December 13, 1864, and appears
in Volume 6 of its Proceedings. Here, again, he was, I believe,
the first to point out that the discrepancy between the observed
and theoretical values of the acceleration was probably due
to the tides.
The subject
has since been developed by Darwin, Thomson, and others, into
a cosmological theory, which is now the only one resting on
a scientific basis. As frequently happens in the history of
science, the first discoverer in a new field has himself to
be discovered by antiquarian research. These early papers of
Ferrel remained generally unknown until after others had reached
the same conclusion. Although this work was astronomical, its
general nature corresponded to that of the whole life-work of
Ferrel. We might describe his field of work as the theory of
cosmical fluid motion. On this theory scientific meteorology
must largely rest, and it was in this way that, from his papers
on the motions of solids and fluids relative to the earth's
surface, which appeared in the Mathematical Monthly, in 1858-59,
were gradually developed a series of researches having a meteorological
bearing.
He was appointed
an assistant in the office of the Nautical Almanac, then at
Cambridge, in 1857. In 1860 he accompanied the writer on an
expedition up the Saskatchewan river to observe the total eclipse
on July 17th of that year. The observations of the total phase
were prevented by clouds. He retained some connection with the
work of the Almanac until about 1879, when he resigned to take
a place in the Signal Office. The description of his work in
meteorology I must leave to others.
II.
FERREL'S
WORK ON THE COAST SURVEY
BY EDWARD
GOODFELLOW,
Assistant United States Coast and Geodetic Survey
William Ferrel
was born in Bedford county, Pennsylvania,, in 1817, was a resident
of Cambridge, Massachusetts, when he received an appointment
on the United States Coast and Geodetic Survey, July 1, 1867.
The work with which he was charged was the investigation of
the General Theory of the Tides, a research to which he had
already devoted much study, and the solution of which he had
advanced quite beyond his predecessors.
Mr. Ferrel's
inquiries and studies as to the influences affecting the tides
led him to give special attention to meteorological effects
on tides, and later the general theory of meteorology received
from him a careful investigation, his contributions to science
on this subject alternating for a series of years with those
on Tides.
His connection
with the Coast Survey continued without interruption until he
tendered his resignation, August 9, 1862, with the intention
of accepting a position in the Signal Service. His resignation
was formally accepted by the Superintendent, but with the expression
of a desire on his part that Professor Ferrel would find time
to complete for the Survey certain tidal investigations which
he had been pursuing with eminent success, and that he would
keep up the supervision of the tide predicting machine which
he had invented.
The theory
and plan of this machine were first submitted to the Superintendent
of the Coast and Geodetic Survey in the spring of 1880, and
its construction was at once decided upon. Various delays occurred
however in obtaining the services of a competent machinist,
so that the actual construction was not begun until late in
the summer of 1881, and it was not completed until the autumn
of 1882.
In August
1880, Professor Ferrel read a paper describing the theory and
plan of his machine before the American Association for the
Advancement of Science at its meeting in Boston.
The machine
was first used in the prediction of tides for the calendar year
1885, to be published in the Coast and Geodetic Survey Tide
Tables for that year.
It was estimated
by Professor Ferrel that the capacity of the machine for doing
work was at least that of thirty or forty computers, and in
response to an inquiry just made (October 8, 1891) Mr. A. S.
Christie, chief of the Tidal Division states that forty computers
would be needed to perform the work done by the machine.
The titles
of Professor Ferrel's papers published in the Annual Reports
of the Coast and Geodetic Survey, and containing his more important
contributions to its work, and to our knowledge of the laws
of the tides and the principles of meteorology are as follows:
Report for
1868. Discussion of Tides in Boston Harbor. Appendix No. 5,
pp. 51-102.
Report for
1870. On the moon's mass, as deduced from a discussion of the
tides of Boston Harbor. Appendix No. 20, pp. 190-199.
Report for
1871. Report of Meteorological Effects on Tides from Observations
by Prof. Wm. Ferrel. Appendix No. 6. Pp. 93-99.
Report for
1872. Maxima and Minima of Tides on the Coast of New England
for 1873. Appendix No. 7, pp. 73,74.
Report for
1875. Discussion of tides in New York Harbor. Appendix No. 12.
Pp. 194-221.
Report for
1875. Meteorological researches for the use of the Coast Pilot.
Part I: On the Mechanics and General Motions of the Atmosphere.
Appendix No. 20, pp. 369-412.
Report for
1878. Meteorological researches for the use of the Coast Pilot.
Part II: On Cyclones, Tornadoes, and Waterspouts. Appendix No.
10, pp. 174-267.
Report for
1878. Discussion of Tides in Penobscot Bay. Appendix No. 11,
pp. 268-304.
Report for
1879. Reference to paper above named (Appendix No. 10 with abstract
of Notice in the "Zeitschrift der Osterreichischen Gesellschaft
fur Meteorologie." p. 4.
Report for
1879. Observation of total solar eclipse July 29, 1878, on summit
of Gray's Peak, Colorado, p. 65.
Report for
1880. Reference to progress made by Mr. Ferrel in the preparation
of Part III of his Meteorological Researches for the Coast Pilot;
to his discussion by the harmonic analysis of the tides at Pulpit
Cove, Penobscot Bay (Report 1878) and to his designs for a tide
computing machine intended to save great labor in the computation
of predicted tides. pp. 2, 3.
Report for
1881. Preparation of paper on barometric hypsometry referred
to, page 2.
Report for
1881. Meteorological Researches, Part III. Barometric Hypsometry
and reduction of the barometer to sea level. Appendix No.10,
pp. 225-268.
Report for
1882. References to (p. 61) to the construction carried on during
the fiscal year ending June 30, 1882, of a tide-predicting machine,
devised by Prof. Ferrel, and constructed under his general supervision
by Fauth & Co., of Washington, D. C.
Report for
1882. Discussion of the tides of the Pacific Coast of the United
States. Appendix No. 17, pp. 437-450.
Report for
1883. Reference in the Report of the Assistant in charge of
Office and Topography (App. No. 4, p. 93,) to the completion
of the Ferrel Tide Predicting Machine, devised and constructed
for the use of the Coast and Geodetic Survey Office, and to
the satisfactory results derived from its use.
Report for
1883. Report on the Harmonic Analysis of the Tides at Sandy
Hook. Appendix No. 9, pp. 247-251.
Report for
1883. Description of a Maxima and Minima Tide-Predicting machine.
Appendix No. 10, pp. 253-272.
The following
named paper, prepared by Professor Ferrel after he had left
the Coast and Geodetic Survey, was published in the Report for
1885. (Appendix No. 13, pp. 489-493.) On the Harmonic Analysis
of the Tides at Governor's Island, New York Harbor.
Professor
Ferrel's interest in the work of the Survey suffered but little
abatement by reason of the severance of his official relations
with it, and in compliance with a request from the Superintendent,
he undertook in 1890 the preparation of a paper which should
embody a history of tidal investigation up to the present time,
and exhibit a comprehensive view of the tidal theory and its
practical application as developed by his own labors and those
of other investigators. In this work, and in another paper involving
the application of the higher mathematics to gravity research,
he had made considerable progress, when he was compelled by
the illness which eventually proved fatal, to give up all mental
labor.
III.
FERREL'S
INFLUENCE IN THE SIGNAL OFFICE.
BY CLEVELAND
ABBE
The quiet
influence of the life and writings of William Ferrel on the
early success and subsequent progress of the Weather Bureau
has, I think, been far greater than we, at first thought, would
conceive of. That his mathematical writings could contain truths
comprehensible to less profound students or that such a quiet
man, unostentatious, diffident, reticent, a student of books
and things rather than of men, should stand as a firm rock against
a flood of popular errors, is contrary to general experience.
Especially might Ferrel seem out of place in Washington where
the influential men are apt to be the ready speakers, the pushing
Representatives and the rich Senators, those who grace the dinner
table or command armies and navies; but when he was transplanted
in 1882 from the scientific atmosphere of the Coast and Geodetic
Survey to the military atmosphere of the Signal Office he found
already engaged in the service four young gentlemen, Messrs.
Upton, Waldo, Hazen, and Russel, congenial spirits who profited
by their intimate association with him.
Ferrel's
work in the Signal Service began with a treatise on the "Motions
of the Atmosphere" which subsequently appeared as "Recent Advances";
but this personal advent was not the beginning of his influence
among us. When on the 4th of February, 1870, the meteorological
work of storm predictions was imposed upon the Chief Signal
Officer what assurance had our legislators that successful weather
predictions were possible? Espy, whose daily weather charts
first opened to our gaze the systematic movements of storms,
and whose enthusiasm and eloquence still lingered in the minds
of the older men, had been these ten years silent in the grave.
Redfield had also passed away although his studies of the Atlantic
hurricanes were familiar to every navigator. Loomis and Coffin
had not been heard from for many years in meteorological matters.
The practical business men and telegraphers of the country knew
well enough that the storms moved more or less rapidly over
the land, but how to predict their motions they knew not. My
Cincinnati bulletins and maps and Lapham's charting of the storm-data
collected by Espy and Henry offered but a meagre basis for empirical
predictions. Accordingly, when in the spring of 1871, I was
asked to write a popular circular* {Suggestions as the Practical
use of Meteorological Reports and Weather Maps. 1st Edition,
Sig. Ser. Print, May, 1871.}explaining to the public something
about the weather map, and the laws by which the weather was
being so successfully predicted from day to day, I could only
introduce into this little work a brief statement of the results
arrived at and published ten years before by Ferrel, who had
already in 1856 correctly unraveled some of the more complex
phenomena, and whose memoir of 1859 is, I think, the starting
point of our knowledge of the mechanics of the atmosphere. This
circular has been quoted as the first introduction of Ferrel
to the professional meteorologists of the world who, up to that
time had been ignorant of, or had misunderstood and neglected
his work. Copies of Ferrel's memoir had indeed been distributed
at the time of its first publication, but he was too far in
advance of the ordinary student of meteorology to be fully appreciated
at that time; he was then busy in astronomical and tidal researches,
his name had frequently appeared in "Gould's Astronomical Journal"**{I
believe that Ferrel's first scientific article was written in
1853 and published in "Gould's Astronomical Journal." It is
therefore interesting to quote the following from a short letter
written at Cambridge by Dr. B. A. Gould in the midst of pressing
engagements: "This afternoon I came to your letter of Oct. 6,
and on opening it learned for the first time of the death of
my old friend Ferrel, who came from near Nashville, some forty
years ago at my earnest counsel, to take up some work on the
American Nautical Almanac. It has been a sudden shock to me;
for, when I last saw him, he seemed vigorous and sturdy."} but
was unknown to the meteorologists of Europe.
It may be
safely stated that from the beginning of my work at Cincinnati,
and from the year 1871 onward in Washington, Ferrel's work was
fully recognized; in fact Professor Joseph Henry himself told
me in 1872 that until he read the synopsis of Ferrel's early
writings in my circular of suggestions, he had not realized
how much light Ferrel had thrown upon the mechanical laws that
prevail in the atmosphere. I shall never forget the intellectual
satisfaction afforded me by reading, in 1855 and 1860, Ferrel's
treatise on the "Motions of Solids and Fluids," as the successive
chapters appeared month by month, in "Runkle's Mathematical
Monthly." They gave me at once the strong conviction that a
successful attack had at last been made on the complex mechanics
of the atmosphere, and that ultimately all would be unraveled.
I have often said that memoir is to meteorology what the "Principia"
was to astronomy; from one point of view this comparison may
seem extravagant for we have all profited so much by the ideas
infused into modern science by the incomparable Newton, that
no one of his followers should for a moment be compared to him;
but personal comparisons aside, I may still affirm that as Newton's
Principia arrested all further vain speculations and turned
the whole trend of thought toward the true celestial mechanics
so Ferrel's memoir served to turn all eyes toward the true atmospheric
dynamics. Doubtless in time his work will be succeeded by more
elegant mathematical treatises just as Newton has been succeeded
by Laplace and other writers, but Ferrel's memoir will always
remain the principia meteorologica. In fact, however,
there really was an intellectual inheritance, for the only books
that Ferrel studied after leaving college were, first Newton's
"Principia" and after mastering that, Laplace's "Mecanique Celeste"
so that his own train of thought, elaborated alone on a distant
western farm, was but the continuation of that which originated
with Sir Isaac Newton.
Imbued with
an appreciation of the mechanical principles set forth by Ferrel
as well as with thermo-dynamic ideas of Espy and his followers
we began the work of daily weather predictions: with the accumulation
of data, it has now become possible to supplement those deductive
theories by generalizations and by the study of "weather types"
and any subsequent increase in the accuracy of predictions must
be attributed to minor and empirical rules supplementary to
the fundamental study of the laws of mechanics and thermo-dynamics.
It is but fair to say that in the absence of actual experience
my predictions of the first few years were mainly of a deductive
character based upon my confidence in the truth of the principles
developed by Espy and Ferrel.
The administration
of Brigadier-General Wm. B. Hazen was distinguished by the introduction
of civilian scientific experts into the Signal Office and when
in due time I expressed desire that Ferrel should be associated
with us he at once authorized me to see on what terms such an
arrangement could be made. I state this thus plainly because
Ferrel's first letter to General Hazen dated August 1, 1882,
has been erroneously spoken of as an application for a position
whereas it was intended merely as a statement of the conditions
under which he would be willing to accept a position. He was
with us four years and his resignation, September 15, 1886,
was prompted (so he states) solely by the consideration that
he had arrived at that age at which he had always contemplated
resigning from active official duties; he had at that time been
engaged for about thirty years in the scientific work of the
government as an employee of the Nautical Almanac Office, the
Coast Survey, and finally the Signal Office, and now at the
age of seventy with a competency that placed him above want
he would retire from obligatory duties and quietly live with
relatives from whom he had long been separated. In an appendix
the reader will find a compilation by Mr. Alexander Ashley,
formerly chief clerk in the Signal Office, enumerating the official
orders and reports relating to Professor Ferrel and I need add
to this list but a few words.
The first
duty assigned to Ferrel was the preparation of a popular treatise
on meteorology; this work occupied his attention for several
years and was finally submitted in manuscript March 2, 1885.
Its publication as one of the professional papers of the Signal
Service was at once decided upon, but when that was found to
be impracticable it was submitted by General Hazen as "appendix
71" or "Part 2" of his annual report for 1885, and is known
as Ferrel's "Recent Advances in Meteorology." But during these
three intervening years several well known papers which may
be considered as special studies auxiliary to the preparation
of that treatise appeared ; such was his report on the "Improvement
of the Psychrometric Formula." This latter was subsequently
made the basis of the new tables used by the Signal Service;
it explained the advantages and the theory of the whirled or
ventilated psychrometer which had been originally used by Espy
and strongly advocated by him ever since 1830.* {* Espy's account
of his experiments reads as though they were entirely independent
of the suggestion of Arago; it is singular that Espy's whirled
psychrometer and Belli's ventilated psychrometer and Arago's
suggestion should have all originated in the same year; one
can scarcely resist the conviction that some paragraph in some
scientific journal should have given rise to similar work in
three different countries.} Ferrel's psychrometric formula represents
a distinct advance in our method of determining the quantity
of moisture in the air and the introduction of the whirled psychrometer
at the Signal Service has led to a great improvement in our
hygrometric data since 1886.
Another study
auxiliary to his "Recent Advances" was that entitled "Conditions
Determining Temperature"; in this under the assumption of the
law of radiation as determined by Dulong and Petit he has given
us the fundamental theory of the temperature of the soil and
the air as based on solar and terrestrial radiation; he has
studied the behavior of a thermometer exposed in the open air
and gave us a practical method of determining the true temperature
of the air; he also gave therein the best theory hitherto published
of the action of the various forms of actinometer, especially
the Arago-Davy actinometer or the bright and black bulb in
vacuo, and has shown the large errors hitherto committed
by the use of erroneous formula. Ferrel supplemented this latter
study by a laborious series of actinometric observations, some
of which were published by him in this memoir. This study also
led him to the further consideration of the general law of radiation
as determined by Stefan and by Weber and by earlier investigators;
these latter studies were subsequently published in the American
Journal of Science and show the limitations of our knowledge
in regard to the this subject. The completion of his treatise
and of his work on the psychrometric formula and tables was
followed in 1886 by a study of the abnormal tracks of certain
storm-centers after which he took up the question of the reduction
of the barometer to sea-level. Ferrel's report on this subject
was published as an appendix in the annual report of General
Hazen for 1886; his formula and tables continued the use of
the reduction to standard gravity which had already, with his
approval, been introduced into the Signal Service methods, but
their peculiar feature consisted in the principles on which
Ferrel founded his method of determining the average temperature
of the fictitious column of air between the barometer and sea-level.
The first of these principles was that the temperature of the
mass of air changes far less than the temperature at the earth's
surface and that approximately the diurnal and annual periods
in the temperature of the mass of air are respectively about
one-fourth and three-fourths of the corresponding ranges at
the earth's surface. The second principle is that the changes
of pressure do not respond immediately to local but to widely
extended changes of temperature, and therefore the proper temperature
to be used in reducing any given observation is the mean temperature
of a long period such as the previous twenty-four hours; therefore
the argument of Ferrel's table is the mean of twice the last
plus the two preceding tri-daily temperature observations. This
latter principle had been presented by me in a paper read by
General Hazen at the Paris meeting of the International Committee
in September, 1885, and notwithstanding the objections urged
against it by Koppen and Leyst it has resulted in giving us
far more satisfactory isobars for the United States than could
be obtained by the use of the simple observed temperatures.
In the autumn
of 1885 a series of lectures and examinations was established
by General Hazen for the benefit of the junior officers of the
service. An important portion of this course consisted of a
series of forty lectures by Professor Ferrel whose manuscript
notes are still preserved and show that it must have been a
rich privilege to have been able to follow his elucidation of
many points bearing on the practical work of weather predictions.
As a member of this board of instruction Ferrel did not hesitate
to express clearly his views as to the standard of scientific
acquirements demanded by the work of the Weather Bureau. In
his opinion the low state of meteorology throughout the world
as compared with the other exact sciences, and even as compared
with climatology, arose from the fact that trained physicists,
mechanicians and mathematicians had not yet been induced to
take up the study of the phenomena of the atmosphere and there
could be no progress until they did so. His vote therefore was
always given in favor of whatever course promised to lead to
the introduction of a high order of talent into the corps of
signal officers.
I have thus
briefly narrated the salient features of Ferrel' official connection
with the Signal Office. I had confidently hoped that he would
be domiciled with us in the Weather Bureau under its new organization
and our disappointment is intensified by the realization that
we know not where in America to look for him on whom Ferrel's
mantle has fallen.
If I have
avoided thus far the expression of any personal reminiscences
it is because Ferrel's general relations to the world of science
are far more important. Suffice it to say that my personal acquaintance
with him began in October 1860, and thirty years of unbroken
friendship and personal intercourse warrant me in saying that
never shall we find one more devoted to scientific investigation
or less ambitious of personal fame and emolument. I have never
known one who, conscious of his eminent ability was so willing
to stop in the midst of his own researches to sympathizingly
assist less competent men in their studies. Ferrel's tenacity
of purpose enabled him to dwell persistently on a subject until
its more complex relations were clear to him and having attained
this deeper insight he communicated it freely to others without
a selfish thought or wish. I deem it the happiest feature of
my life to have read his works and to have known the man.
IV.
FERREL'S
CONTRIBUTIONS TO METEOROLOGY.
BY PROFESSOR
W.M. DAVIS
National
pride is awakened in scientific successes as well as in examples
of more material prosperity, and it never had with us a better
justification than in reviewing the work done in the science
of Meteorology by Professor William Ferrel. He found it treated
in the most illogical and unphysical manner. Without external
encouragement and assistance , he turned investigation into
an entirely new direction, and thereby gave a new aspect to
Meteorology; and this at the age of thirty-nine, when few men
begin work on new subjects, and in a country which at that time
gave much less attention to scientific matters than it does
now. Undaunted by lack of general recognition, he continued
and enlarged his studies, publishing his researches at considerable
intervals of time, and gradually obtaining recognition among
scientific men; but this affected him as little as neglect,
for he was at the end as at the beginning as purely a scientific
worker for the sake of science as any many our country has produced.
Ferrel's
method is often characterized as mathematical or as deductive;
but I think it should be more justly called a logical method.
Mathematicians are, I understand, disposed to question the accuracy
and completeness of some of Ferrel's formulae. Without being
able to follow their objections, I am willing to accept the
justice of their criticisms and their preference for what is
called the more elegant work of some of Ferrel's successors;
because I believe that the essential quality of Ferrel's work
in meteorological science should be described not as mathematical
but logical. Before his time, meteorology was in great part
empirical. Dove and Redfield both illustrate this quality in
their studies; and Espy's brilliant departure from it led him
in part into error by reason of his lack of knowledge of physics.
If we compare
the results of early meteorologists with those reached by Ferrel,
it appears that the reason the earlier workers were less logical
and finished in their methods was in part owing to their lack
of understanding of the logical method itself; in part also
to their want of sufficient acquaintance with the various departments
of knowledge other than observational meteorology that the logical
method draws upon; but the greater reason for Ferrel's remarkable
advance beyond his predecessor's lay in his native genius -
in his extraordinary success in discovering suggestions that
deserved pursuit, and in his wonderful skill in pursuing his
suggestions to the point of demonstration.
To appreciate
the truth of these general statements, let us recall the condition
of meteorology at the time when Ferrel prepared his first essay
in 1856. The theory of the general circulation of the atmosphere
was then but slightly altered from the form in which Halley
and Hadley had left it more than a century before; and the alterations
were not particularly to its advantage. Dove's theory of equatorial
and polar currents, the first southwest, the second northeast,
in this hemisphere, was generally accepted; unless replaced
by the unphysical theory of Maury, as advocated in his popular
Physical Geography of the Sea. Both of these theories still
have their advocates, although they have been abundantly disproved.
Espy's condensation of the theory of cyclones was better grounded,
but was incomplete from the omission of essential considerations.
Redfield can hardly be said to have had any theories; he was
very guarded in such matters, and when theorizing he was not
remarkably successful.
I now wish
to emphasize what appears to me the chief elements of Ferrel's
success in extending our science from the time it was so poorly
understood.
The first
thing needing emphasis is relatively negative. Ferrel was not
an observer. He does not seem to have been at all blind to the
occurrence of external facts; but he appreciated that the proper
understanding of meteorology must be based on wider observations
than could be made by any one person. Therefore instead of attempting
to make advance by direct observation, he studied the best records
and results that he could obtain, always keeping well informed
on new discoveries, and showing excellent discrimination in
the selection of new material. His writings do not teem with
bibliographical notes, he was not particularly interested in
making references to every author that he read, for he deemed
some of them as of no great value; we may however, be sure that
any of the references he gives to the observations or discussions
of others will lead us to material of value.
At the time
of his early essays, he quoted the facts of Maury and the results
of the Wilkes' expedition, particularly in regard to the general
westerly winds and the prevailing low pressure in the far southern
latitudes. He employed the results obtained by Coffin in his
great studies on the winds of the globe; later, he utilized
the records of the Signal Office, and especially the discussion
of these records made by Loomis. But throughout his work it
is uncommon to find facts referred to as of his own observation.
Being thus
at all times well informed as to the facts of the science, he
proceeded to the next legitimate step in his investigations,
namely: the search for adequate theories for explanation of
the facts. I cannot speak of his methods here from personal
knowledge, but the impression gained from reading his books
is that he advanced by a remarkably direct step to the outline
of a theory that commended itself at once by its apparent sufficiency,
and that afterwards on closer examination proved itself worthy
of belief.
It is this
step in investigation that seems to me most clearly the mark
of genius. The discoverer seldom knows how he reaches his discovery;
it occurs to him; it rises spontaneously in his mind; it is
an intuition, an inspiration. I presume that all this may be
summarized by regarding it psychologically as an example of
unconscious cerebration; the mind being well supplied with the
two essentials for this curious process; first a good knowledge
of facts; second, a good knowledge of general principles bearing
on these facts. Then, given time, the spark of genius fuses
these two kinds of information into a theory by which one explains
the other.
Ferrel was
evidently well equipped for this part of his work. He studied
incessantly. He was sufficiently informed in physics and mechanics
to be able to follow their methods in a comprehensive manner;
and he kept himself informed on the advances in these sciences
as fully as possible. It was this double acquaintance with both
the special facts of meteorology and the general principles
of physics and mechanics that place him above the other meteorologists
of his time.
Just as a
knowledge of physics and mechanics enabled Ferrel to invent
good theories, so a knowledge of their mathematical expression
and treatment carried him safely over the difficulties of the
next step in investigation, namely: the extension of the theoretical
suggestions, quite independent of observation for the moment,
to the consequences involved in their adoption. It does not
appear to me that investigators as a rule recognize consciously
enough the importance of this part of their work; and they may
here take a lesson from Ferrel. It is manifest from all his
work that he had full confidence in the importance of deductive
methods, properly employed and guarded; he represents to me
in this respect one of the best examples of logical reasoning,
and the sufficiency of such reasoning to carry one from correct
premises to sound conclusions. Among his predecessors in meteorology,
Espy, of all others, made the longest steps in this direction;
but his pace was faulty; his education was not well enough grounded.
It might indeed by remarked that Ferrel's education was also
poorly grounded; he had not much of what we call a university
education; but he had the power of his genius to lead him over
this difficulty. He reasoned well. However wide open the eyes
must be for the detection of facts in the first place, however
well one must acquire all the results reached by others and
carry them forward by memory, the further advance in investigation
may be made in the dark and alone. It involves only strictly
reasonable deduction from premises to conclusions, along the
road of logical methods. In this stage of work, it is manifest
that Ferrel's mathematical ability stood him in good stead.
It is now criticized as not being of the most finished style;
but it sufficed for the hard work of breaking the way; it cleared
away difficulties and left open ground for finer methods to
follow. Although his treatment is in mathematical language,
the essentials of his problems are simple mechanical and physical
conceptions. To those of us who do not easily read the language
of algebra, and who are told that Ferrel's writings in this
language are not graceful, it may be a satisfaction to recognize
that the most important part of Ferrel's work was not simply
the mathematical treatment of certain ideas, but the introduction
of those ideas themselves. This is, I believe, admitted by modern
students. Ferrel's ideas in meteorology were wonderfully original;
his mathematical treatment of them was sufficiently exact to
demonstrate their value; but the ideas are of greater value
than the treatment they received. It is perhaps because of too
great attention to mathematical form and relative neglect of
the idea that it clothes the English mathematicians and meteorologists
as a whole have been so little affected by Ferrel's suggestions.
His principles as yet have not really touched meteorological
science in that conservative country.
Although
the deductive parts of Ferrel's work are prominent, they do
not take an undue share of the whole; and in this I find the
best justification for describing his work in its entirety as
logical. After observation comes intuition ; after intuition
comes development in deductive form; after deduction comes comparison
with facts; and in this latter respect I think Ferrel is simply
masterful, not faultless but masterful. His work throughout
is too largely characterized by his own peculiar methods to
be regarded as perfect; it was not to be expected that his demonstrations
of anything so complicated as the motions of the atmosphere
could have geometrical completeness; indeed, the steps by which
he crosses lapses of fact or formulae are sometimes leaps, and
the skill with which these leaps are made give strong character
to his work. Being thus marked by a distinct personality, we
need not expect to find it perfect, but are content to call
it masterful. The chapter in his "Meteorological Researches,"
in which he confronts the deductions from theory with the facts
of observation gives an admirable lesson in method as well as
meteorology. It is not marred by special pleading; it is fair
and clear; it recognizes omissions and looks for their supply
by future observations; it makes no pretense at absolute completeness
or infallibility. It is thoroughly judicial. The same final
process of comparison of deductions from theory with fact is
carefully attended to in all his studies; in as many cases as
possible the comparisons are quantitative as well as qualitative;
and in this they deserve our most careful imitation. We find
many examples in meteorology of imperfectly considered theories,
put forth as if calling for belief; untested, not even legitimately
extended to their inevitable conclusions on the basis of existing
knowledge concerning their postulates; they simply appear plausible,
and are then announced as if prepared for acceptance. We find
many others characterized by carelessness in deductions. We
find some whose deductions are not impartially confronted with
the facts. We find very few so carefully guarded at every step
of their development as Ferrel's are. At the time when his first
essays were published, they were distinctly in advance of the
times in these estimable respects. We may therefore claim for
Ferrel that among his contributions to meteorology was the invaluable
one of setting a good example for other investigators. Well
informed as to fact, and acute in sifting out error; well informed
in principles that might bring explanation to the facts; aided
by native genius in perceiving the relations of these general
principles to the special facts; well armed with mathematical
processes for the deductive extension of his theories; and calmly
judicial and impartial in testing his results. Work pursued
by such a man in such a method may well be called logical; it
is truly scientific in the Johnsonian sense of leading to demonstrable
knowledge.
The contributions
mad by Ferrel to our science may be now more specifically considered.
They may be summarized under the general circulation of the
winds; the more local circulation of cyclones; and the even
more restricted mechanism of tornadoes.
The general
circulation of the atmosphere has long been ascribed to the
difference of temperature between the equator and poles, whereby
the isobaric surfaces of the atmosphere must be deformed from
the level concentric shells that they would form under the action
of gravity alone, and become tilted from level positions, so
that gravity might act on them and produce motion. As long as
the difference of temperature is maintained, as long as the
sun shines, the winds must continue to circulate.
The obliquity
of their courses was recognized before 1700, and for the trade
winds explained imperfectly by Hadley in 1735. From his time
to that of Dove and Maury, no considerable additions were made
to the theory; but these two eminent meteorologists attempted
to extend the former statements by determining the course in
which the return polar current of temperate latitudes must flow;
and both concluded that in this hemisphere it should come from
the northeast; in the other hemisphere from the southeast. Dove
and others thought they recognized this return current in the
northerly winds that alternate with the southerly during the
passage of areas of low pressure, which we now call cyclonic
storms. Accompanying this view of the theory of the winds, one
generally finds the prevailing high pressure of the tropical
latitudes, which came into notice shortly before the middle
of this century, referred to the crowding of the equatorial
overflow as it moves along the converging meridians towards
the poles; although the weakness of this explanation should
have been seen when it was known that from the tropical belts
to the poles, where the convergence of the meridians was most
rapid, the pressure decreases. The attempts to explain this
decrease by the presence of water vapor have been signal failures,
although among the English meteorologists hardly any other reason
for polar low pressure is mentioned.
It is stated
by McAdie in his account of Ferrel's life that Maury's popular
Physical Geography of the Sea was the means of bringing these
erroneous views to Ferrel's attention. This almost gives reason
to be obliged to Maury for putting his theory in so convincingly
impossible a form. Accepting the initial cause of motion to
be the difference of equatorial and polar temperatures, Ferrel
amended the former statement of the theory chiefly by introducing
a correct measure of the value and application of the deflective
force arising from the earth's rotation. This had been fully
worked out by mathematicians before him, notably by Poisson,
who applied it even to the deviation of projectiles from rectilinear
flight; and a curiously brief and overlooked statement of the
deflective forces had been made by Tracy, in 1843, who then
first properly applied it correctly to the courses of the winds,
but only in a limited way. Ferrel mastered the matter, and showed
that the air must sidle along the poleward gradients, at increasing
velocity and increasing deflection from the meridians until
its deflective force is directed nearly towards the equator;
then the small component of gravity by which its motion is accelerated
compounded with the deflective force produces a resultant, acting
forwards in the direction of motion, which must be equal to
the resistances, of whatever origin. Steady motion is thus attained.
The eastward motion thus produced, almost at right angles to
the meridians, attains certainly a high velocity in the upper
air, where the resistances are small; and as higher latitudes
are reached, the deflective forces acting away from the poles
overcome the high pressure that would be produced by differences
of temperature and simple convectional motion on a non-rotating
earth, and produce a polar low pressure, characteristic of a
convectional circulation on a rotating earth. The poleward gradients
are thus greatly steepened in the upper air; but in spite of
this, the interchange of air between equator and pole is retarded,
by reason of the oblique course that the winds are forced to
take on their way. The eastward velocities, almost at right
angles to the gradients, are truly greater than any velocities
that might be attained in a simple convectional circulation
on a non-rotating earth; but the poleward components of motion
are weaker than they would be in the absence of deflective action.
Not only
are the upper gradients steepened towards the pole; the lower
gradients, which would be turned equatorward on a non-rotating
earth, are now turned poleward also; and the only gradient towards
the equator are in the trade-wind belts of the lower atmosphere.
When this fact is first apprehended , there is sometimes difficulty
in understanding how the air can return from pole to equator
"against the gradients," as it is expressed. It returns in virtue
of the excessive eastward velocity that it gained on the steeper
gradients aloft, while approaching the poles; for this eastward
velocity supplies it with an equatorward deflective force by
which it "climbs the gradients." Thus, in our hemisphere, Ferrel
determined that the equatorial overflow would produce west-southwest
winds, and the return polar underflow, west-northwest winds,
until, entering the latitudes of the trades, their course turned
around to northeast. From the time when this beautiful principle
was introduced, there should have been no further mention of
high-level currents from the northeast, above our usual west
winds; but unfortunately, apparently truthful error holds its
place long when popularly advocated, against the more rigorous
conceptions of truth, announced but not urged.
The scheme
of the general circulation of the winds requires a slight but
essential amendment by the introduction of a lower member of
the circulation whose velocity is reduced by friction below
that needed for it to climb the gradients; and which therefore
obeys the gradients and flows obliquely towards the poles as
a west-southwest wind in this hemisphere; a west-northwest wind
in the other. This form of statement was first made by James
Thompson of Edinburgh, who appears to have come independently
on the whole idea in 1857; but he stated it very briefly (British
Association Report, 1857) and it was much more fully, and I
believe independently, discussed by Ferrel a year or two later.
(See further in Science, ix, 1887, 540.)
Ferrel's
view of the general circulation is now accepted in its essential
features by most meteorologists ; and were it not for the silence
regarding it on the part of some of the British school, I should
regard it as universally acceptable. But in Great Britain, it
finds little recognition - unfortunately for the advance of
the science in that country - and even in the report of the
Challenger Expedition, no clear understanding of so important
a matter as the low pressure around the poles is to be found.
In Germany, the case seems to be understood better; partly from
a knowledge and appreciation of Ferrel's work; partly from independent
studies leading to the same end; studies in which the originality
of the author's does not appear to me to be so great as is sometimes
claimed for them. The essential of all modern treatments of
this problem was stated by Ferrel in 1859, and more fully elaborated
in later essays, some years before it was treated by any German
student; this essential being that an equatorial-polar convectional
circulation on a rotating earth must consist chiefly of oblique
winds from a western quarter, with high velocities nearly at
right angles to the gradients; and that the initial high pressure
about the poles, due to low temperature, will be reversed to
low pressure by the excessive centrifugal force of the whirling
winds, thus leaving a belt of high pressure near the tropics.
The second
important contribution by Ferrel concerns the cyclonic storms
by which the general circulation is frequently interrupted;
and, although it appears to me that recent objections to the
convection-condensation theory, introduced by Espy and developed
by Ferrel, have great weight, yet it must be remembered that
these objections apply as far as we can now see only in the
case of the cyclonic storms of the temperate zones, or to the
cold season cyclonic storms of the torrid zone; while the typical,
symmetrical cyclones of the torrid zone must still be regarded
as truly conventional phenomena; and as such the explanation
given them by Ferrel still applies
I shall not
here consider the special features of this theory. The reader
may find it fully stated in Ferrel's Popular Treatise on the
winds; but a paragraph may be given to one feature of the theory
that must certainly be regarded in its favor; namely, the correlation
that it establishes between conventional cyclones and the general
planetary circulation; for when theoretical views bring out
simple relations between apparently remotely related phenomena,
this may certainly be claimed to their credit. Ferrel draws
a clear comparison and a sharp contrast between the general
circulation and the cyclonic circulation. Both are cyclonic,
inasmuch as they whirl; but one has a cold center; the other
a warm center. Gravity here does work on the lower inflow, and
the winds thereby gain enough energy to carry them out of the
upper part of the whirl against the gradients. In the general
circulation with a cold center, the high central or polar pressure
due to low temperature is reversed to a low pressure by the
centrifugal force of the whirl; the whirling inflow aloft gains
sufficient energy to carry out the underflow against the gradients.
It is manifest that as thus stated the two phenomena are presented
in their simplest form; but is it not also manifest that they
are presented in their essential truth?
The objections
recently urged against the convection-condensation theory of
cyclones, as developed by Ferrel, appear to me to have much
force; but in this I see no reason whatever for regarding Ferrel's
theory as inapplicable to the cases of tropical cyclones. Indeed,
the interesting matter in this connection is not so much where
Ferrel was wrong, as why he was wrong. Mention has already been
made of the resistances which the effective resultant accelerating
force of the general circulation must overcome. Ferrel does
not seem to have included under these resistances the irregularities
of flow which might certainly be expected to arise in an atmosphere
whose temperature and humidity decrease irregularly from equator
to poles, and whose under surface rests on an uneven earth.
A considerable tangling of adjacent currents must arise from
the irregularities in the poleward gradients and frictional
resistances; and if it is possible for these tanglings to produce
whirls, then cyclonic storms might be produced in this way.
Ferrel's writings do not give any indication that he considered
this possibility; if considered at all, it was not regarded
as of sufficient value to be put in print. This seems to me
the most of a defect in his theories; much more a defect than
inelegancies of mathematical form, for it is in a sense illogical;
and I mention it here chiefly as an earnest of my desire to
place his work at its true value, not simply to praise it all.
I mention it without hesitation, for if this is Ferrel's chief
omission, it is still fair to regard his work as masterful;
not perfect, but masterful.
It was fitting
that an American meteorologist should be the first to account
for the severity of tornadoes, whose violence is so distinctly
an American meteorological phenomenon. The student may search
the literature of the science through and through; he will find
nowhere else any adequate consideration of the cause of the
terrific blast of the tornado. He may wander from one unsatisfying
theory to another; as the doubter wanders from creed to creed,
finding no rest for his unhappy disbelief; until at last he
reaches the true faith, on which he rests with confidence and
comfort. In the confidence that grows between passengers on
a long sea-voyage, I heard some twenty years ago a young Chilean
student, on his way to Germany, recount his mental disturbance
while his religious ideas were unsettled; until at last he had
come out of doubts on reaching a faith that satisfied him. No
such unhappy ordeal has afflicted me; but I have experienced
feelings that were perhaps akin to it when trying to teach something
about tornadoes before I had come on Ferrel's writings. Other
writers left me dissatisfied and in doubt; Ferrel's chapter
on tornadoes in his Meteorological Researches led me out of
the darkness, and since then I am glad to say I have been a
zealous advocate of his faith, believing that in his work we
find such guidance and inspiration as is given to men; not infallible
although reaching far ahead of the knowledge of its time; human
in containing possible errors, but more than is common to most
of humanity in containing a large share of permanent truth.
Those who
wish to follow and appreciate Ferrel's work must not learn of
it through brief mentions such as this. It must be studied in
its original form; and to those who are prepared for its understanding,
it must be most inspiriting and suggestive. I have here only
mentioned a few of its leading features, under the headings
of the most distinct additions made to meteorology; but as these
were introduced by allusion to the carefully logical and complete
method of investigation that characterized all of them, they
may be followed by reference to another lesson, a personal lesson
that all meteorologists and all scientific men may learn from
Ferrel's life. His was a life of simple living, of steady hard
work, of slowly recognized success; without controversy, without
effort to spread his views, with almost an indifference to their
general acceptance; with confidence that the elements of truth
in his works would stand, but without undue pride in the strong
position that he saw them gain. In the midst of our struggles
and ambitions we may to advantage recall his simple ways; and
though without hope of his genius we may learn from him the
value of patient persevering study, and the dignity of sincere
effort towards - not the reputation that follows successful
work, but the truth which is followed by unsought renown. Here
was a man of known by name to hardly more than a few hundred
of our millions; known personally to fewer still in a vast population
that is ever ready to recognize notoriety; and yet his quiet
work greatly advanced the bounds of human knowledge. It is a
curious commentary on renown to name Ferrel, of whom the great
world knows nothing, as the most eminent meteorologist and one
of the most eminent scientific men that America has produced.
V.
PROFESSOR
WILLIAM FERREL
BY DR. FRANK
WALDO
It would
have been a great privilege to have been able to attend in person
this memorial meeting in which so many meteorologists have met
to pay a tribute to the memory of William Ferrel. But as such
personal attendance is denied me I most willingly accept the
suggestions which I have received to contribute a short note
which will at least show my great respect for the character
and work of him who has just left us.
My acquaintance
with Professor Ferrel has extended over the past ten years,
and during the first part of this time I was permitted to know
him somewhat intimately as he was quite frequently, for him,
a guest at my dinner table, and thus the personal side of his
character became known to me. All who have known him must testify
to his gentle and unassuming manners, yet they must have felt
with me that it was the simple dignity of greatness which was
shown in his intercourse with others. I shall never forget the
feeling of respect, and to a certain degree awe, which I felt
when I stood before him for the first time. It was in his little
solitary room at the Coast Survey Office, in the fall of 1881,
that I first visited him to talk over a proposed new edition
of his famous paper of 1859-1860. His kindly greeting and pleasant,
although briefly worded, conversation did not fail to kindle
within me the hope of having his future friendship and interest.
The last
time I saw Professor Ferrel was about two years ago when with
his usual kindly feeling he crossed the State of Ohio to spend
a day with me at my home in Cincinnati. He had then spent the
greater part of two or three years in Kansas and Missouri and
was evidently homesick for the East where he had lived almost
uninterruptedly for about thirty years, while he was employed
in the Nautical Almanac Office, the Coast Survey, and the Signal
Office.
His scholarly
habits were too strong to allow him to remain in the west where
his business interests, to which he devoted the last years of
his life, were centered. The extract, given below, from a letter
to me, shows that student companionship was necessary to his
happiness. His frequent journeys to Boston showed the pleasure
he had in visiting this literary center. Once when I asked him
why he was going to Boston, he replied, "Oh, I am going to read
up the back numbers of Nature" (the English journal).
Another example
of his quiet humor may be cited in his proposing, in an after
dinner conversation, the title of "A Meteorology for Babes"
for his then forthcoming work on "Winds."
Speaking
to his removal back to the east from Kansas City to Martinsburg,
Virginia, near Washington, he says:
"It is nearer
to places where I can have scientific associations and access
to scientific libraries, both of which were almost entirely
lacking in the west."
Professor
Ferrel's bachelor habits undoubtedly tended greatly to give
to his writings the thoughtfulness and reflection which characterize
them; but unlike most bachelor scientists he did not accumulate
an extensive library. That he was wrapped up in his own researches
is plainly shown by the fact that his writings do not show that
he was in any way influenced by the writings of Guldberg and
Mohn and other eminent investigators in the field of dynamical
meteorology. He never quoted them, nor did he introduce into
his work of analysis the more finished methods of these continental
writers.
The details
of the usual meteorological work were not of high interest to
him; he only sought so much of this material as would be useful
to him in making generalizations. He was not considered a great
theoretical mathematician, but he had a wonderfully clear idea
of the use of mathematical formulae for expressing physical
truths. Still his knowledge of theoretical or pure mathematics
was sufficient to satisfy the ambition of most men.
His most
important work was undoubtedly that in the Mathematical Monthly,
1859-1860. This alone, had he written nothing else, would have
assured his fame in after years, when it would have been discovered;
but he had the strength of conviction that his work was right,
and after a period of 25 years from the first publication of
his theory he had the satisfaction of finding his labors appreciated
the world over. While the same general theme runs through his
various memoirs on atmospheric motions, yet he has varied his
form of analysis so that in the continued reiteration of his
theory during the past 35 years there is little sameness, and
always some new view is presented which has made the subject
clearer.
It was this
continued presentation of the subject, and also in a measure,
aided by the spreading of his views by Abbe in America and Sprung
in Europe, which aided in finally procuring for Professor Ferrel
the wide recognition of his work which he enjoyed the last years
of his life.
Had he written
only the paper of 1856, his ideas would probably have been as
totally unconsidered as those of Tracy published a few years
earlier.
The often
used illustrative story of "Columbus and the Egg" fits Professor
Ferrel's work with more than usual exactness. He found only
the loosest reasoning applied to the formation of a theory of
the general atmospheric motions. The subject was considered
one of such extreme difficulty as to cause mathematicians to
shrink from investigating it; and indeed the mathematical tools
had not then been invented which would allow of an absolutely
correct treatment of the problems involved, and so he was obliged
to use, what seem to some, unwarrantable mathematical reasoning;
but the agreement of his results with those obtained by others
at a later time shows that he was not in error.
Looking back
at the matter from the present point of view it seems impossible
to consider Ferrel's early conception of the atmospheric circulation
in any other light than such an inspiration as comes to a very
limited number of our race, who at the proper time are permitted
by our Creator to point out to us the paths for us to tread
if we will continue in the line of progressive study of nature.
With what
a thrill of pleasure must Ferrel have pictured to himself for
the first time the atmospheric circulation as a whole. Heretofore
meteorologists had viewed the matter by piece-meal, and as we
may say, from a point of view here on the earth's surface, down
at the bottom of the great sea of air. Ferrel's conception allowed
him to take the comprehensive view which he would have had could
he have taken the earth in his hand like an orange, and thus
have pictured before him as a whole, the mighty currents of
air and their secondary phenomena, the connection of which could
not be seen by viewing them in detail.
Such a clearing
up as this view gave of the fogginess which had enveloped the
atmospheric motions can almost be compared to the change in
geographical conceptions which followed the discovery that the
earth is globular in form.
If any one
doubts this, let him read up the subject of atmospheric motions
in Schmid's Meteorologie, 1860, and then in Sprung's Meteorologie,
1885, and consider that we have mainly Ferrel to thank for the
difference in the two pictures there presented.
Professor
Ferrel had undoubtedly the most philosophical mind which has
yet devoted itself to the study of meteorology; at least in
modern times.
In closing
I wish to mention that the paper on his life and work, which
appeared in THE AMERICAN METEOROLOGICAL JOURNAL sometime ago,
seems to me to well represent his character as manifested to
all of his associates and admirers.
Princeton,
New Jersey, October 15, 1891.
VI.
THE
OFFICIAL RECORD OF PROFESSOR WILLIAM FERREL
IN THE SIGNAL OFFICE
Compiled
by ALEXANDER ASHLEY
The records
of this office show that Professor William Ferrel in a letter
to General Hazen, dated August 1, 1882, desired that his services
be regarded, in some measure, as advisory and expert in certain
scientific matters to which he had been given especial attention,
and as not requiring his attendance at the office, more than
the half of official hours, if he did not wish it, (though he
would probably be there much more) and, as such, he would have
it understood that, for the most part , he would have that embrace
some part of every day, so that he would be consulted with regard
to any matter, almost at any time. Much of the time he might
be absent being devoted to reading and study on the subjects
connected with his duties at the office. These terms were accepted
by the Chief Signal Officer in a communication to Professor
Ferrel, dated August 5, 1882, appointing him "Professor of Meteorology"
in the Signal Service with salary at the rate of two thousand
dollars per annum. This was accepted by Professor Ferrel in
a letter dated August 7, 1882, and he was so appointed August
10, 1882. This position was held by him until September 15,
1886, when he tendered his resignation which was accepted to
take effect September 30, 1886.
August 11,
1882, there was added to the series of "Professional Papers"
published by the Signal Service, "Recent Mathematical Papers
concerning the Motions of the Atmosphere." Part I: "The Motions
of Fluids and Solids on the Earth's Surface, by Professor William
Ferrel, reprinted with notes by Mr. Frank Waldo"; also, October
27, 1882, there was added to said series "Popular Essays on
the Movement of the Atmosphere by Professor William Ferrel,"the
edition to consist of 2,000 copies. On November 2, 1883, there
was added "Temperature of the Atmosphere and Earth's Surface,
by Professor Ferrel," the edition to consist of 2,000 copies.
November
3, 1883, Ferrel was directed to make a report in regard to the
changes suggested by Professor C. Abbe, Assistant, in the form
of publication of the Signal Service reports in accordance with
a plan sketched by the International Committee on Meteorology
at their reunion at Berne, and referred to him (Ferrel) to make
extracts, etc., for careful study.
April 28,
1885, he was appointed member of a board to recommend a course
of instruction to fit certain officers for the "indication"
work of the Signal Service.
October 15,
1885, a Board was appointed to consider all matters referred
to in a letter of Mr. W. M. Davis, Secretary of the New England
Meteorological Society, and also the whole subject of the "Monthly
Weather Review," for the purpose of recommending any changes
they may determine necessary; said board to call on Professor
Ferrel for such views as he may have upon any questions before
it.
May 28, 1885,
he was appointed Instructor and Lecturer on Meteorology for
the benefit of a class of officers in their second term of instruction
beginning February 1st and ending June 30, 1886.
December
19, 1885, he was appointed a member of a permanent Board to
which was referred all matters submitted for publication by
members of the Signal Service, either as Professional Papers,
Signal Service Notes, or otherwise, which might be germane to
the work of the Service.
March 10,
1885, there was added to the series of Professional Papers published
by the Signal Service "Recent Advancement in Meteorology" by
Professor William Ferrel.
May 6, 1885,
Professor William Ferrel was announced as "Assistant" to the
Chief Signal Officer.
March 19,
1886, Professor Ferrel was, for convenience of administration,
directed to report to Professor Cleveland Abbe, Assistant, for
duty in the Study Division, but not to effect any change in
his duties. March 26, 1886, was directed to assume charge of
the Study Division during the absence of Professor Abbe. March
31, 1886 the instructions assigning Professor Ferrel to duty
under Abbe were revoked. June 16, 1886, was appointed member
of a Board to consider what was known as the "Study Room Work,"
as to authority, utility, methods, and limitation, and to recommend
a full scheme for the coming year with such changes from present
methods as may seem proper.
July 15,
1886, was appointed member of a Board to report upon the proficiency
of each member of the class of officers in the course of study
being pursued by them, as shown by the monthly examinations
held, and the practical "indications" and field work done.
August 2,
1886 the following duties were assigned to Professor Ferrel:
(1) The preparation and revision of all the official meteorological
reduction tables for use in the Signal Service;
(2) The reduction of special meteorological observations;
(3) The study and report upon special questions raised by the
Indications Board in connection with the indications work of
the Service;
(4) The study of the effect of wind force, and direction on
barometric pressure.
The following
synopsis of communications and reports of Professor Ferrel indicate
in general the nature and scope of his work while on duty with
the Signal Service:
(1) August
17, 1883 submitted a plan for a proposed treatise by him on
meteorology to be confined to the higher parts of the subject
only, "there being a number of elementary treatises, very good
so far as they go;" refers to papers already prepared by him,
especially on the Temperature of the Atmosphere and Earth's
Surface, a paper containing 156 pages of manuscript. This plan
approved by the A.C.S.O.
(2) Manuscript
in four (4) extensive papers, as follows:
(a) Temperature
of the Atmosphere and Earth's Surface.
(b) Conditions determining Temperature.
(c) Actinometry.
(d) The Distribution and Variations of Temperature.
(3) November
1883 submits report in reference to Resolution 15 of the International
Meteorological Committee, and also on Professor C. Abbe's recommendation
that all barometric readings be reduced to the standard force
of gravity at the latitude 45o and sea-level - referred to him
for report.
(4) December
10, 1883 submits report of his researches in the Theory and
Efficiency of the Arago-Davy Actinometer and states that he
has gone somewhat extensively into the subject in his professional
paper; recommends that a pair of the thermometers be made to
order for use early in the spring.
(5) July
31, 1884, reports that since sending in his last reports he
has completed a chapter on the General Motions and Pressures
of the Atmosphere, and will now commence a chapter on Cyclones,
Tornadoes, Waterspouts, etc.
(6) January
2, 1885, submits report of work done since December, 1884, on
the manuscript of the work on Meteorology on which he is engaged,
having added 97 pages, and is about finishing the part on psychrometry;
the whole work to contain about 450 octavo pages in print.
(7) February
28, 1885, submits report of various kinds of work performed
during the month.
(8) March
31, 1885, submits report of work done during the month; has
considered and studied Colorado and Arizona psychrometric and
dew-point observations - those of one year at each place - the
only thing which impairs their usefulness is the lack of ventilation,
especially in the Colorado observations. Thinks the whole series
of these observations should be thoroughly discussed in order
to obtain from them their greatest value; and would like to
undertake the work if instructed to do so; would like a cheap
computer to assist him in the simpler parts of the computations;
has been reading several works pertaining to psychrometry so
as to be better prepared for the above work.
(9) March
2, 1885, submits manuscript of work on which he has been engaged,
entitled "Recent Advances in Meteorology" (1929 Sig. 1885).
The manuscript is not on file, in this office, but is probably
with the manuscript Annual Report in files of the War Department.
The work is published as Appendix 71, Annual Report, C.S.O.,
1885.
(10) April
30, 1885, reports having been engaged upon the subject of improvement
of the psychrometric formula with reference especially to determining
whether experiments at Colorado Springs and Pike's Peak required
the same value of the constant in the formula at these different
altitudes; claims that experiments thus far favor this view,
and indicate that the [sic] final result obtained at an altitude
of 6,000 feet will be the same as that obtained by Sworykin
at sea-level, with a ventilated psychrometer, confirming the
theory of the formula.
(11) June
1, 1885, submits report of work done during May in connection
with observations taken at Colorado Springs and Pike's Peak,
from which he has found the same results as others have, that
the wet bulb thermometer stands higher often, at and near saturation
than the dry one, which is puzzling and so far unexplained;
has also studied tracks of storms in relation to the areas of
high barometer and the isothermal lines from the charts of 1878
and 1879.
(12) June
30, 1885, reports having finished his studies of the abnormal
tracks of storm centers and prepared a report; has also worked
up in a preliminary and approximate manner the data from Colorado,
especially that from the Trail House, by Prof. Marvin. These
experiments and those at Colorado Springs give very satisfactory
results. Thinks the Alluard hygrometer the most perfect of all
and that it will not be necessary to make any change in the
data; having commenced the final working up of the material
will have plenty of work on hand during the next few months.
(13) July
20, 1885, submits summary of work done by him during the fiscal
year ending June 30, 1885.
(14) July
20, 1885, requests leave of absence with permission to make
a communication to the American Association at Ann Arbor, Mich.,
during the last week in August, upon the subject of psychrometry
and other work on which he is engaged in the Signal Office;
reports his return from said leave September 1, 1885.
(15) July
31, 1885, submits the report of work done during the month "on
the improvement of the psychrometrical formulae for the purpose
of preparing for publication dew-point and humidity tables for
the use of the Signal Service."
(16) September
4, 1885, submits report (also signed by Professor T. Russel)
on the relative value of spherical and cylindrical bulb-thermometers
for meteorological observations.
(17) October
3, 1885, submits report of work done during September, 1885,
continuing the work on the "Dew-point and Relative Humidity
Tables."
(18) October
31, 1885, submits report of work done by him during the month,
especially referring to the deduction of the most probable value
of the "constant" in the psychrometric formula to be used with
the whirled psychrometer.
(19) November
11, 1885, encloses copy of new tables adapted to the whirled
psychrometer, and in a very concise form, much more convenient
than those heretofore used. States that they are now ready for
print and distribution to the stations, if thought desirable
(Vapor Tension, Dew-point, and Relative Humidity Tables.)
(20) December
8, 1885, submits his opinion in regard to the two sets of tables
for barometric reduction to sea-level referred to him for examination.
(21) December
31, 1885, submits report of work done during November, 1885;
reports having finished the preparation of the psychrometrical
tables and made out a copy of them in a form for use on stations;
has also been engaged in collecting the whole material and arranging
it for the final report upon the whole work.
(22) December
31, 1885, encloses revised tables and submits report on reduction
of barometric readings to sea-level.
(23) December
31, 1885, submits report of work done during the month; was
engaged in preparing the report on psychrometric work and tables,
and in studying and examining the work done on the reduction
to sea-level, etc.
(23) December
31, 1885, submits report of work done during the month; was
engaged in preparing the report on psychrometric work and tables,
and in studying and examining the work done on the reduction
to sea-level, etc.
(25) January
30, 1886, submits a detailed report upon the International Meteorological
Observations, and their value in obtaining any further results
from them in addition to those which have been already deduced;
has examined and studied carefully the records and charts of
these observations in the "Fact Room" and has also posted himself
with regard to the work which has already been done upon them,
and the results obtained.
(26) January
30, 1886. During the month has examined and studied the records
of the International Meteorological Observations in the "Fact
Room," and has also been preparing himself for his course of
lectures to be given to the army officers, to commence February
1.
(27) February
10, 1886, submits a report concerning slow motion of the cyclone
of November 22-25, and the motion of the high barometric pressure
of December 25, 1885.
(28) April
30, 1886, submits report of work done during the month, being
mainly on the subject of reduction of the barometer to sea-level;
having reduced the temperature and barometric observations for
all the stations to sea-level by several methods and charted
the results to ascertain which are most satisfactory, has formed
three charts from the results of the temperature reductions
and also three charts of isobars; has adopted the rule of allowing
one degree of temperature for each six hundred feet of altitude
in all reductions of temperature from the high stations down
to sea-level, and gives his reasons for this rule. Is now ready
to begin the computation of the new tables.
(29) June
1, 1886, submits report of work done during May on barometric
tables on which he was then engaged.
(30) July
1, 1886, submits report of work done by him during June, referring
to researches in regard to the elevations of stations over the
western high plateau not determined from railroad leveling,
and expresses doubt as to the correctness of altitudes derived
from R.R. levelings; has finished all the tables of altitudes
of stations over 1,500 feet; balance of tables for low stations
can all be furnished in a week.
(31) July
10, 1886: the Indications Board having under consideration Professor
Abbe's proposed tables for the reduction of the barometer to
sea-level recommends that the system should be perfected and
all the tables computed under the direction of Professor Ferrel;
this work was accomplished by him and his final report submitted
July 10, 1886, and the tables adopted.
(32) July
31, 1886, submits report of work done during the month in the
way of completing tables for reduction to sea-level for all
stations not previously prepared (among others those for Mt.
Washington and Pike's Peak) having had to perform most of the
work himself.
(33) August
31, 1886, reports on Reduction of Barometric Pressure to Sea-Level
and Standard Gravity.
(34) August
31, 1886, submits report of work done during the month, the
time having been mostly occupied in preparing report on the
"Reduction of Barometric Pressure to Sea-level and to Standard
Gravity," and in the revision of proofs of Appendix No. 71 of
the Chief Signal Officer's report for 1885; has completed about
240 pages.
(35) September
25, 1886, submits report on "Schoch's Paper on the Application
of Spherical Functions to the Temperature of the Earth's Surface."