[ 4IO ] 



In this table we fee, 1°. That during the vernal equinox the 

 'heat differs but little from the mean heat really obferved in all 

 latitudes, and perhaps flill lefs from the maximum of real heat. 

 Yet, except in latitude So**, it is always higher, both from the 

 quantity of rays loft in paffing through the air, and from the 

 quantity refleded by water and the frequent interpofition of 

 elouds, &c. 



adly. We fee that the aftronomical heat conftantly increafes 

 with the height of the latitudes, as the duration of the folar rays 

 more than compenfates for their obliquity, when the fun is in 

 the northern tropic ; but the real heat decreafes as the latitudes 

 increafe, becaufe this theoretic compenfation does not take place, 

 from the interpofition of clouds and the accefs of cooler winds, 

 and the increafed refietftion from the furface of the water. 



The different temperatures of .different fummers are ultimately 

 refolvable into the different direflion of the winds during thofe 

 feafons, and the different eledrical ftates of the atmofphere, the 

 foulh or fouth-eaft producing not only clouds which intercept the 

 fun's rays, but alfo copious rains or hail, which, defcending from 

 great heights and occafioning a copious evaporation, cool the air 

 to a great degree. The north and north-eaft, on the contrary, 

 unlefs immediately fucceeding great rains, (for then they increafe 



the 



