j : Effect of Heat upon Volume of Air. 15 

 fil. The absolute humidity of the atmosphere is much greatest in 





so. 



&. 

 0. 

 46. 

 40. 

 S3. 



so. 



20. 



the mean of many years' ob-^ 

 servation at the. Magnetic 

 and Meteorological < )bserva- [ 

 tory at Toronto, in ( 1 anada, ' 

 and at the Slate Agricult- ' 

 ural Colleges at < )roiio, in 

 Maine, and at Lansing, in 

 Michigan, are shown by the 

 accompanying engravings. 



E/i'H* -f Ifntt nnd of Cold 

 H in >, i Hi,- Volttmr of Air. 



L tJ 



02. It is a rule that heat 

 tends to expand all bodies, 

 whether s.ilid, liquid, or gas- 

 eous, and that cnoliug tends 

 to reduce their volume. 



63. When any substance 



expands, it absorbs "latent 6. Relative Humidity at throe American Sta- 

 , , , tions through the several Months, for a Series of 



luat, and becomes colder. Years. 



