406 WAIDNER, DICKINSON AND CROWE : OCEAN TEMPERATURES 



All of the apparatus was carefully calibrated before leaving the 

 laboratory. The surface thermometer was mounted with its flat 

 face directly against the inner surface of the ship's f-inch plates, 

 about 6 feet below the water line. Simultaneous measurements 

 of temperature, made with a sensitive mercurial thermometer in- 

 serted in the water and with the surface thermometer and recorder 

 mounted as above, showed that the sudden changes in sea water 

 temperature were indicated by the recorder without any signifi- 

 cant time lag. The suspended system of the D'Arsonval galvanom- 

 eter of the recorder was so carefully balanced by the makers 

 that the records were Entirely unaffected by the rolling and pitch- 

 ing of the ship. As used, a change of 1°C. corresponded to a 

 movement of the pen of 18 mm. on the record sheet. The dis- 

 placement of the paper was about 60 mm. per hour. 



Fig. 1. Record of June 17, 1912 



Temperature records. Practically continuous temperature rec- 

 ords were obtained from June 4 until July 10, 1912. The tempera- 

 tures recorded ranged from 3° to 25°C. The balance point of the 

 recorder was changed to bring the temperature records on the 

 paper by the insertion of suitable known resistances in one arm 

 of the Wheatstone bridge circuit of the recorder, the calibration 

 of the surface thermometer being made with the corresponding 

 resistances in the circuit. 



Figure 1 shows the temperature record obtained on board the 

 U.S.S. Chester, June 17, 1912. Several small bergs or "growlers" 

 were sighted on the horizon at 9.45 a.m. Almost simultaneously, 

 the record shows a sudden fall of temperature from 8?7 to 7?3 C, 

 or nearly 1?5 C. At this time the ship was over 10 miles from the 

 nearest of the growlers. The temperature continued to fall irregu- 



