1882.] On a Deep Sea Electrical Thermometer. 



93 



pencil of light. The temperature of the surface was 76° *5. Having 

 lowered to 15 fathoms, at end of one minute the pencil of light was 

 9° to the left of zero on the scale. At the end of five minutes it was 

 22°, and at the end of ten minutes still 22°. A number of experi- 

 ments were made with regard to the time necessary for the resistance 

 coil to assume the temperature of the water. Five minutes was 

 decided on as being necessary and sufficient, and was adopted in all 

 succeeding lowerings. 



The first lowering was to 400 fathoms, the temperature at that 

 depth being 40°. The cable was then reeled in to 200 fathoms, when 

 the current was made. There was found to be no deflection, the tem- 

 perature of the water in the copper vessel having risen from 40° to 

 43°' 5. This temperature agreed with that at 200 fathoms when 

 lowering to the same depth. 



During the experiments there was a light south-east breeze, and a 

 very smooth sea. They lasted from 7.18 p.m. until 1.30 a.m., but 

 special care was taken with every reading, and it is probable that 

 fifteen minutes would be a fair average time for each observation with 

 the electrical apparatus. 



The results are given in the Table. 



I. 



II. 



Depth in 

 fathoms. 



Reading of 



attached 

 thermometer 

 coil. 



Reading of 

 Miller-Casella 

 thermometer. 



Depth in 

 fathoms. 



Reading of 

 attached 

 thermometer 

 coil. 



Reading of 

 Miller-Casella 

 thermometer. 



Surface 

 5 

 10 

 15 

 20 

 30 

 50 

 75 

 100 

 150 

 200 

 300 

 400 



76° -5 



76-5 



76-5 



69 



58 



54 -25 

 54 -25 

 52 -5 

 51 

 46 

 43 5 

 40-5 

 40 



76° -5 



76-5 



76 



68 



58 



54 



53 '5 

 52 5 

 50-5 

 46-5 

 43 5 

 40-5 

 40 



30 

 50 

 100 

 150 

 200 



54° 



54-25 

 50 -5 

 46-5 

 43-5 



o 



54 

 53 -5 

 50-5 

 46 5 

 43-5 



Early on the morning of August 12th another serial to 800 fathoms 

 was taken with the Miller-Casella thermometers, and immediately 

 after with the electrical apparatus. Several readings were taken from 

 the surface to 100 fathoms, and then the coil was reeled out to 800 

 fathoms, and the readings taken as it was drawn up. 



