38 



WORK OF THE CARNEGIE AND SUGGESTIONS FOR FUTURE SCIENTIFIC CRUISES 



observation, we noticed a change in the color of the sea. 

 It lost its grayish-green tint and became clear blue. 

 The sea-water thermograph had shown great variations 

 in temperature for several hoiirs, and now read 75° 

 Fahrenheit. At noon it had been only 46°. We were in 

 the Gulf Stream. 



The ship had been supplied with a solarimeter, for 

 measuring the quantity of radiation reaching the earth 

 from the sun. We gave it a first trial on May 13, but it 

 was apparent at once that conditions would not be favor- 

 able for using it on a sailing ship. The effects of rolling 

 and pitching were minimized by mounting in gimbals the 

 sensitive photoelectric cell; but the greatest difficulty 

 was shade cast by the rigging, and back reflection from 

 the lofty sails. After a few more trials it was found im- 

 practicable. The information it gives is used in studies 

 of world weather. It would have made an excellent ad- 

 junct to our meteorological program, for we were con- 

 cerned with he at -transfer's between sea and air, and with 

 evaporation rates in various regions. 



While we had been anchored in St. Mary's River, a 

 gyroscopic stabilizer had been installed on the earth in- 

 ductor. It was hoped that this device, in addition to the 

 gimbal mountings, might make the coil more independent 

 of the ship's motion than the gimbals alone. But all at- 

 tempts to use it had failed, because the strain when the 

 constant-speed motor was started or stopped was too 

 severe on the shafting. Several changes in design would 

 be necessary before it could have been employed, and 

 after a few more trials it was discarded for the time being. 



It was always a rule on the Carnegie to analyze and 

 put in form the scientific data collected on each leg of 

 the cruise, for the immediate use of hydrographers and 

 oceanographic workers ashore. This feature of our 

 routine kept the observers occupied between observing 

 periods at sea and for several days after reaching port. 



For example, tables were drawn up showing the 

 values of declination, horizontal intensity, and inclina- 

 tion, as given by the latest British, German, and Ameri- 

 can charts for the regions traversed by the ship. 

 Against these we tabulated the measurements made on 

 the voyage, so that errors in the charts might be cor- 

 rected in future editions. Differences of as much as If 5 

 in declination were discovered on the passage from New- 

 port News, with corresponding errors in the other ele- 

 ments. This serves to emphasize the importance of re- 

 peated surveys of the earth's magnetism, to determine 

 the changes constantly taking place in the distribution of 

 this mysterious natural force. 



By early September our procedure at an oceano- 

 graphic station had become somewhat standardized, and 

 it might be of interest to describe just what takes place. 

 On the morning of September 15, we are about two hun- 

 dred miles from Barbados. At eight bells the new watch 

 comes on deck and finds everything in readiness for 

 heaving to. The winch is uncovered, the wires are 

 threaded through blocks to the davits, outboard-plat- 

 forms are in place, and rvinning gear is laid out on deck 

 ready for shortening sail. With the sound of the ship's 

 bell still in our ears, the men dash to the tackle, blocks 

 rattle and yards creak as the squaresails are taken in. 

 The lower topsail alone is not furled, and is set aback to 

 check our headway. Then one after another the fore- 

 and-aft sails come down until only the mainsail and mid- 

 dle staysail remain. The ship is now hove to and comes 

 up into the wind or falls off alternately with the helm 

 alee. 



The oceanographic team consists of four members 

 of the scientific staff (Captain Ault, Soule, Seiwell, and 

 Paul), the mate (Erickson), the engineer (Leyer), and 

 the watch officer with his four seamen. Practically all 

 operations take place on the quarter-deck. Mr. Erick- 

 son immediately attaches the bottom sampler to the 

 piano wire, drops it over the stern, and signals to Leyer 

 to pay out on the winch. Meanwhile Captain Ault and 

 Soule are attaching the Nansen bottles, with their revers- 

 ing thermometers to the aluminum -bronze wire. As 

 these bottles are lowered one after the other ui a long 

 series, Paul reads the meter wheel. When the desired 

 length of wire has been paid out he signals to Leyer to 

 apply the brake. Another bottle is attached, more wire 

 is paid out. This goes on till some eight or ten bottles 

 are strung on at intervals of from five to five hundred 

 meters. 



At this station we are to reach down five thousand 

 meters, so it will be necessary to send down two bottle 

 series. The first, or "short series" will consist of nine 

 bottles lowered to 5, 25, 50,. 75, 100, 200, 300, 400, and 

 500 meters respectively, while one bottle is reversed at 

 the surface. As the greatest difference in temperature 

 and chemical salts occurs near the surface, the intervals 

 are fairly short there. But in the "deep series," which 

 is sent down later, the bottles are spaced 500 meters 

 apart. The strain on the wire would be far too great 

 were we to lower twenty bottles at once. 



During this time Seiwell has put out the plankton 

 nets. These are lowered in series, much as the bottles, 

 but only three are used; one goes to 100 meters, another 

 to 50 meters, and the third to the surface. Microscopic 

 life in the sea is chiefly concentrated near the surface 

 because sunlight does not penetrate water very far. All 

 animals depend on plants for food, directly or indirectly, 

 and of course it is sunlight which is utilized as a source 

 of energy by plants such as diatoms. 



Ten minutes are allowed for the lowered Nansen bot- 

 tles to take up the temperature of their surroundings. 

 Captain Ault now slides a brass "messenger" down the 

 wire to reverse the first bottle in the series. As each 

 bottle tips over, its own messenger is freed to proceed 

 to the next bottle, and so on down the line. It takes from 

 ten to forty minutes for the messenger to reach the low- 

 est bottle. When they are inverted in this way, the valves 

 automatically imprison a sample of water from the de- 

 sired depth. Also, the mercury capillary of the ther- 

 mometer separates in such a way that the temperature 

 of that level can be read off on deck, no matter what 

 temperatures are encountered on the way to the surface. 



It is not possible to raise the bottle series until the 

 bottom sampler has struck. With depths like five thou- 

 sand meters this may take an hour. When the signal is 

 given that the piano wire is slack, Leyer ceases to pay 

 out, Erickson reads the meter wheel, and Captain Ault 

 measures the vertical angle made by the wire. From 

 these readings the depth can be calculated. Soule has 

 meanwhile made an echo sounding to check this value. 



The winch then brings up the bottle series and bot- 

 tom snapper together. The bottles are removed from 

 the wire and placed in sheltered racks. Paul collects 

 water samples for chemical analysis, and Soule takes 

 specimens for salinity determinations. When this is 

 done, the deep-sea thermometers are read and the Nan- 

 sen bottles prepared for their second plunge--this time 

 to greater depths. 



While all this is going on, Seiwell or Paul has put 



