492 



Dr. J. F. Main. 



wooden pillar, which supports the upper lever. The greatest 

 variations of temperature inside the inner box were given in Experi- 

 ment 3, and, on the days mentioned in the record of Experiment 2, by- 

 two thermometers, maximum and minimum, attached to the roof of 

 the inner box. The centres of the bulbs were about 7| cm. from the 

 roof. 



