292 Prof. Bischof on the Temperature of 



depth for ascertaining the temperature, all possible influx of 

 water was prevented. Lastly, the fact that the results obtain- 

 ed at a certain depth exactly coincided, whether observed at the 

 bottom of the well or at the same point afterwards, when the 

 work had been carried on to 106 — 6.9, 213 — 1.8, or 819 — 8.7 

 feet below that point, puts it beyond doubt that nothing could 

 have tended to disturb the observations. 



The temperature was observed with the utmost care by 

 means of a maximum thermometer. The results shewed so 

 exact a coincidence among each other, as well as with those of 

 a common thermometer in the less considerable depths, that the 

 greatest confidence may be placed in them. The following in- 

 cludes the whole series : — 



In the first series the thermometer remained in each station 

 so long as was found necessary by experience for the exact ob- 

 servation of the temperature. 



The second series was undertaken in order to ascertain 

 whether, by sinking the thermometer more or less rapidly, any 

 difference in the results would ensue from the heat caused by 

 he friction of the metallic cylinder against the sides of the well. 

 However the presence of the water would lead us to expect a 

 negative answer to this question. 



