Figure 13. Ekman piezometer - In 1904 Vagn Walfrid Ekman of Switzerland, a member of the Central Laboratory of Christiana, was tasked with studying the compressibility of sea water in relation to salinity and temperature. He devise d a new model of piezometer, first used in 1905 and first described in 1908. It s most important readings were from the PRINCESS ALICE II in 1906.

Figure 14. Ekman piezometer (laboratory model) - In parallel with measurements made in the sea deployed from the PRINCESS ALICE, Vagn Ekman devised a piezometer for use in the laboratory which he most probably used at Christiana at the Central Laboratory using methods recommended by Thomas William Richards.

Figure 15. An oxygen probe - This device is much more modern than those examine d previously. Two electrodes form a galvanic chain with the sea water in which they are immersed. the current measured depends on the diffusion of oxygen released under an electrode. This instrument was manufactured commercially by the German firm Harmann and Braun in about 1957.

Figure 16. The autonomous oceanographic measuring device. The Crouzet firm developed this instrument after a study at the Naval Weapons Laboratory. It was used to determine temperature, pressure, and velocity of currents. It was deployed from the surface and then sunk to the bottom. Upon returning to the surface, it would transmit its observations to a surface vessel.

Plate 3. Using the Hodges shock absorber in order to bring a dredge trawl back aboard H. M. S. PORCUPINE [after Sir Wyville Thomson, 1873.]

Figure 17. Model of the HIRONDELLE's winch. From the beginnings of Prince Albert I of Monaco's oceanographic explorations, he became occupied with equipping his vessels with basic indispensable deck equipment and tools includin g winches, reels of cable, etc. He gave the engineer Jules LeBlanc responsibili ty for this but became a principle collaborator in this area.

Figure 18. Model of the HIRONDELLE's small reel - another device probably made by Jules Le Blanc.

Figure 19. Model of the HIRONDELLE's large reel - another device probably made by Jules Le Blanc.

Figure 20. A Nansen counting pulley - used to determine the length of cable reeled out on an oceanographic station.

Figure 21. Model of Hodge's shock absorber or accumulator. This device was invented in 1852 by Richard Edward Hodges. It was used to aid in launching and retrieving heavy objects suspended from cables or ropes, particularly when a vessel is subject to motion if the seas are high. It was first used in oceanographic work off H. M. S. HYDRA in 1867.

Figure 22. The BLAKE shock absorber. This device also used the principle of the elasticity of rubber to absorb the shocks incurred on a cable or line when launching or retrieving heavy objects at sea. This device was first used in the winter of 1878-1879 on the Coast and Geodetic Ship BLAKE while under the scientific direction of Alexander Agassiz.

Figure 23. The HIRONDELLE enclosed spring dynanometer. This type of shock absorber employed a metallic spring instead of rubber, which was fragile and alterable. It was designed and built by Jules LeBlanc following the suggestion of Prince Albert I of Monaco. It was first used in 1888 on the HIRONDELLE and for many subsequent years and scientific campaigns.

Figure 24. A spring shock absorber. No information is available concerning the inventor or the use of this device.

Figure 25. A roller guide, devised by Jules Le Blanc following a suggestion of Prince Albert I of Monaco. Used to minimize chance of tangling cables during oceanographic operations.

Figure 26. Ball bearing swivels devised by Jules Le Blanc to prevent untimely twisting of cables, getting them caught on hull projections, or even breaking of lines.

Figure 27. The Aime Olive, a large weight attached to the cable immediately before a bottom dredging device. This weight would keep the dredge in contact with the bottom. Although used by fishermen prior to its oceanographic use, Aime's adaptation of this concept apparently marked its first use in oceanography. Circa 1840.

Figure 28. Lead weights used to depress the front of a net or trawl being dragged across the bottom.

Figure 29. Dredging harrows used to stir up the bottom in order to capture the small crustaceans and other creatures that lived there. This instrument was fabricated at the Oceanographic Museum in 1939.

Figure 30. Nansen releasing devices used for closing plankton nets. This device was invented by Fridthof Nansen about 1900 and apparently used aboard the MICHAEL SARS. A messenger activated this mechanism which in turn "strangled" the net by closing off its open end and capturing the fauna in the net.

Figure 31. Aime messenger ca. 1843. The Frenchman Georges Aime was among the fir st to systematically employ the principle of a messenger in order to communicate with submerged instruments. The messenger was sent down the line and activated some form of opening or closing mechanism on the sampling instrument. Aime used only solid messengers which had to have the line or cable run through them.

Figure 32. Enjalbal messenger, fabricated by Louis Enjalbal, a mechanic on the PRINCESS ALICE, in 1906.

Figure 33. Riva messenger, fabricated by Paul Riva, the mechanic on the EIDER, a small research vessel operated by the Oceanographic Museum at Monaco in the early 1900's.

Figure 34. Gilson messenger, devised by Professor Gustave Gilson of the University of Louvain and delegate from Belgium at the Permanent International Council for the Exploration of the Sea , to intiate the operation of his plankton meter.

Figure 35. Zwickert messenger, possibly devised by the German instrument maker Adolf Zwickert who was known for creating numerous scientific instruments.

Figure 36. Cros messenger. These messengers were fabricated by the mechanic Jean Cros of the Oceanographic Museum at Monaco at the request of Dr. Jean Brouardel. The messengers were very narrow and streamlined and capable of being used with modern equipment. They were probably tested about 1958 aboard the WINNARETTA SINGER.

Figure 37. Spring messengers with rotating closing mechanisms. In 1923, the Danish scientist Martin Knudsen described and tested this type of messenger. The goal was to find a form and weight of messenger that would rapidly descend a cable without becoming entangled. Subsequently messengers of this type were most frequently used on research ships throughout the world.

Figure 38. Hinged messenger, a model first proposed by the hydrographic laboratory at Copenhagen in 1914. The models shown are of a later date.

Figure 39. Spiral opening messenger - in the design of these messengers, the groove which allows the device to be placed on the cable is in the form of an S or Z. The messenger is locked on the cable by means of a rotating part at the top of the messenger. A simpler non-locking version of this messenger was produced by HYTECH, a California firm.

Figure 40. Thoulet soluble cartridge messenger for delayed release of instruments. These "soluble weights" were designed to initiate the functioning of an immersed device at a pre-determined time. Thoulet had apparently designed this device for use with sampling nets . He started tests with these in 1893 in Lake Gerardmer and provided samples for Prince Albert I to use at sea.

Figure 41. Kiel Commission Hydrometers - these hydrometers were created in 1870 at the initiative of the Commission of Scientific Studies of German Waters at Kiel.

Figure 42. Buchanan hydrometer made at the request of John Y. Buchanan during the CHALLENGER Expedition. These were instruments with variable weight and volume. Two of these instruments were improved and modified by Victor Chabaud and used during the Belgium Antarctic Expedition from the BELGICA from 1897 to 1899.

Figure 42 (continued.) Various Buchanan hydrometers with associated apparatus in their instrument cases.

Figure 42 (end.) A Buchanan hydrometer instrument case with the initials of John Y. Buchanan.

Figure 43. Nansen total immersion hydrometer, an instrument of variable weight and constant volume. The fact that the instrument is completely immersed during use explains the term "constant volume." Its principle was first put forth by Giuseppe Pisati in 1890 and adopted by Fridthof Nansen in 1900. In 1901 it was used by Jacob Schetelig, Nansen's assistant, from the MICHAEL SARS.

Figure 44. Thoulet total immersion hydrometer, designed by Professor Julien Thoulet for the purpose of studying the density of water from depth for the purpose of studying sub-surface currents. Professor Thoulet produced this relatively small sampling device of 200 cubic centimeter volume with Professor Henry Adolpe Chevalier of the University of Nancy.

Figure 45. Pettersson small chain hydrometer, designed by Professors Otto and Hans Pettersson in 1917. This instrument eliminated difficulties associated with the surface tension of the sample as well as variations of volume. A small metal chain helped achieve a balance by compensating for the buoyancy of the float as a function of the density of the liquid.

Figure 46. Regnault pycnometers, instruments first mentioned by the physicist Henri-Victor Regnault, a professor at the College of France, in 1843. These instruments were used to measure the density of liquids which he was studying to obtain their specific heat.

Figure 47. Sprengel pycnometer, first described by the German chemist Hermann Sprengel in 1873. He had used this instrument for a number of years. It had great precision and was easy to fill. Later the German chemist Wilhelm Ostwald partially modified it, replacing the original U tube with a single-sided one.

Figure 48. Knudsen pycnometer, described by the Danish physicist and hydrographer Martin Knudsen in 1902. This instrument was designed to make precise laboratory measurements of the density of sea water.

Figure 49. Fery refractometer, an instrument first suggested by Julius Hilgard of the United States Coast and Geodetic Survey to measure the density of sea water by relating the index of refraction of a liquid to its density. The instrument shown was developed by the Frenchman Charles Fery in 1891.

Figure 50. Berget double deviation refractometer, developed and devised by the Frenchman Alphonse Berget, professor at the Oceanographic Institute. From about 1911 onward, he was concerned with developing an instrument to measure the density of a liquid at sea by a method that would not be affected by the ship's motion. He described the pictured instrument in 1925.

Plate 4. Knudsen Burette, an apparatus for the determination of salinity of water samples.

Figure 51. The Knudsen Burette, introduced by its inventor at the first international conference for the exploration of the sea in 1899, became one of the most used instruments in the world for determining salinity of a water sample.

Figure 52. Richter burettes, fabricated by Carl Richter at an indeterminate date. It is certain that the firm of Richter and Wiese made this type of burette for measuring salinity up until the recent times.

Figure 53. Schmidt burette - although little information exists regarding this instrument, it probably was invented by the German chemist Paul Schmidt for use on the VALDIVIA expedition in 1898-1899.

Figure 54. Pellet burette - this instrument was produced by the French chemist Henri Pellet. It uses the same principle as that of the Richter or Schmidt burette. It has an automatic zero level, in which the reactive reservoir is pressurized by a rubber bulb.

Figure 55. Boutron and Boudet hydrometric devices for measuring density of fresh water.

Plate 5. Knudsen apparatus for the determination of the nitrogen and oxygen levels in sea water. Model with three burettes.

Figure 56. Jacobsen device for extracting gases from sea water. This device was invented by Professor Oscar Georg Jacobsen, a member of the German Baltic expedition of 1871-1872. It was based on an instrument conceived by Robert Bunsen. Water samples were obtained by Meyer bottle.

Figure 57. Dittmar device for extracting gases from sea water. This device was described by the British professor William Dittmar of Anderson's College in Glasgow. He used it to analyze sea water sampled during the CHALLENGER expedition. It complemented the use of the Jacobsen apparatus used by John Y. Buchanan during the CHALLENGER expedition.