4 L. A. Bauer — Gravity Determinations at Sea. 



made on vessel at anchor ; his present results for Ay differ at 

 times from the previously published ones by 0'15 cm . 



Suggestions have been received from various sources that it 

 would be highly desirable to include, if possible, gravity work 

 on the "Carnegie." At the request of President AVoodward, 

 I consulted in 1905 Professor llelmert, Director of the Geo- 

 detic Institute at Potsdam, as to the possibility of attempting 

 the boiling-point method on the "Galilee," which had just been 

 chartered for magnetic work in the Pacific Ocean. As the 

 result of Hecker's experiences on vessels exceeding the ton- 

 nage of the "Galilee" by eight times and more, llelmert did 

 not feel warranted in advising the undertaking of similar work 

 on our vessel; he thought it best under all circumstances to 

 await the conclusion of Hecker's labors. No attempt was 

 accordingly made on the "Galilee." 



However, on the " Carnegie" it was decided to include 

 determinations of the temperature of the boiling point of 

 water in the regular routine work aboard, the prime purpose 

 being to obtain data for controlling the corrections of our ane- 

 roids. The instrumental equipment was in accordance with 

 this aim ; it consisted merely of two boiling apparatuses of the 

 pattern described and figured in the British Antarctic Manual 

 of 1901, p. 94, two specially constructed thermometers by 

 Green, of Brooklyn, N. Y., graduated into one-hundredths of 

 a degree centigrade from 97 - 6° to 107 - 7°, the length of one 

 degree being about 40 millimeters, and one Green mercurial 

 marine barometer. In all 106 determinations of the boiling 

 point were secured on the First Cruise, between Sept. 1909 

 and Feb. 1910, four of which had to be rejected because of 

 manifest errors, leaving 102 values and representing 75 differ- 

 ent points. While a few observations were made at the very 

 beginning of the cruise, by Mr, J. P. Ault. the navigating 

 officer, the work did not begin regularly until the vessel left 

 Falmouth on November 6, 1909, but thereafter to Madeira, 

 thence to parallel 20° North and return to Brooklyn via Ber- 

 muda, the observations were made almost daily by Dr. C. C. 

 Craft, and that too at times under very trying conditions of 

 weather. A week's series or more was obtained at each of the 

 ports, — Brooklyn, Falmouth, Funchal (Madeira), and Hamilton 

 (Bermuda). 



The two boiling-point thermometers were read visually, with 

 the aid of a hand lens, to the nearest - 001° by estimation of a 

 tenth of a space 0*4 n " n long ; and the mercurial barometer was 

 read directly by vernier to - 01 inch and by estimation to 0*005 

 inch or less. The pumping of the barometer, which is of the 

 ordinarj' marine type, amounted at times under the severe 

 conditions of sea encountered on the return trips to as much as 



