88 



TRANS. ST. LOUIS ACAD. SCIENCE. 



In order to correct for varying declination, the magnet Cg was 

 removed at each reading, and the position of C^^ read. 



A glycerine damping was used, so that the scale was perfectly 

 steady. When Cg was removed, it was always retained in the 

 jacket, lying on cotton batting. 



For the cool temperatures ice-water was used, and the same 

 was kept at constant temperature by cooling the room first, and 

 then feeding the water in the jacket by a constant drip of ice- 

 water. 



In the first determination, at yh. 49m. a.m., all the magnets 

 had been thus in position all night, so that the temperature of Cg 

 was determined with sufficient certainty. 



Determination of q for C^. 



March 20, 1879. 



Cj 7 suspended. Glycerine damping. 



Cg deflecting 21 inches west; north pole west. 



Temperature of room 58°. 3 F. 



Cg gradually warmed. 



TEMPERATURE OF ROOM 70° 



