1894.] Atmospheric Temperature, especially during Fb'hn. 123 



observed temperature is given. In tbe fiftb and sixth columns the 

 corresponding differences between the temperature of the air and 

 that of the thermometer which would cause the observed rate of 

 change of temperature are given ; with these and the observed tem- 

 peratures we obtain the amended temperatures of the seventh 

 column. Although it was snowing on the 26th the air was perfectly 

 still, and the rate of cooling corresponding to the " range " 80 sees, 

 has been applied. Had the rate of cooling of the thermometer in 

 tbe still air of a room been taken the difference between amended 

 and observed temperatures would have been nearly twice as great. 



It was interesting to know what could be obtained with a record- 

 ing thermometer of ordinary type, and in Table V the results of some 

 observations made in Cambridge with a Richard's recorder are 

 given. 



Table V, giving the Time in Seconds required by a Richard's Record- 

 ing Thermometer to change its Temperature by 1 C. for a given 

 Difference of Temperature between it and the Air. 



The figures in this table are taken from the curves drawn by the 

 instrument on a drum revolving once in forty-eight minutes. The 

 instrument was allowed to take the temperature of the room, then 

 exposed in the shade in the open air when a fresh breeze was blowing 

 and allowed to remain there until it had taken the temperature of the 

 air. It was then transferred to the room, and allowed to rise until it 

 attained its temperature. 



