Dec. 14, 1871] 



NATURE 



127 



a — Kncnsed hiilh 

 'b.b--Ebonilc prolciioi 



rcinnvcd 

 c-India rubber .to 



prevent Jar 

 (I -Copper case. 



DEEP-SEA THERMOMETER USED BY THE HVI 



It will be observed that the water pumped into the 

 cylinder was a little warmer than that in the cylinder ; but 

 as the valve through which it passed into the cylinder is 

 near the top, while the bulbs of the thermometers were at 

 the bottom, the small difference it could have made in the 

 upper water could not have affected them. 



The result of the foregoing E.xperiments (some rejected 

 in forming the mean) : — 



o'oiyS, calorific effect for each 250 fathoms' pressure. 



o'lS „ „ 2,500 „ „ 



It would seem almost unnecessary, for the purpose for 

 which this paper is prepared, to record the above observa- 

 tions at all, so small is the result ; but as the amount of 

 heat caused by compression is supposed by some to be 

 much greater, it has been thought best to give it. 



Experiments to Determine the Amount of Heat 

 Produced by Friction. 

 To ascertain if any error could arise from heat created 

 by friction in a thermometer passing rapidly through the 

 water, one of Casella's Hydrographic Office pattern was 

 tovved astern of one of the fast river-steamers {\aiad), 

 keeping the thermometer well submerged by means of a 



