Chemical and Physical Notes 



transferred to the room, and allowed to rise until it attained 

 its temperature. 



In this way two sets of curves were obtained, consisting 

 of three curves in still air and three in a fresh breeze. The 

 results are not very concordant, for, although the scale of time 

 is very open one minute occupying 5 mm. the temperature 

 scale was very close, i occupying only I mm. The object, 

 however, of the table is to show what can be expected from 



TABLE XIV. Giving the Time in Seconds required by a 

 Richard's Recording Thermometer to change its Tempera- 

 ture by i C.for a given Difference of Temperature between 

 it and the Air. 



an instrument, of the kind in the measurement of changes of 

 temperature. The results obtained in the open air would 

 necessarily vary somewhat, because, although a fresh breeze 

 was blowing all the time, a fresh breeze varies in velocity. 



In order to obtain the best results from a thermometer, it 

 should be exposed to uniform ventilation. This can only be 

 effected by artificial means, and they necessarily tend to efface 

 sharp variations of temperature. 



Departing from the mercurial thermometer the writer has 



