THEORT of RAIN. 85 



at any time, above its mean temperature for the feafon, and a 

 change {hall happen from a ferene flcy to cloudinefs, we have 

 reafon to expect, that the extreme heat will be temperated, and 

 the atmofphere confequently cooled. But, if the temperature 

 of our atmofphere be below its mean heat for the feafon, then, 

 from the change of clearnefs for a cloudy {ky, we have reafon 

 to look for a change from cold to hot. 



FROM this alfo we have a proper explanation of a general ap- 

 pearance, with regard to the ferenity of the fky, in every cli- 

 mate, and in the oppofite feafons of fummer and winter ; for 

 this ferene fky, or clear atmofphere, is perfectly confident with 

 the two extremities of temperature ; that is, with that of heat, 

 upon the one hand, and of cold, upon the other. It is only a 

 mixture of thofe two extremes, that is to fay, of hot and cold 

 atmofphere, which produces, at the fame time, cloudinefs to 

 the fight, and temperance in relation to the fenfe of heat and 

 cold. Thus will be explained a common obfervation, with re- 

 gard to the weather of this country, that the air is always cold, 

 below its mean temperature for the feafon, when the iky is 

 clear. The country people allege that it is then froft, even in 

 the midft of fummer. They probably find hoar-froft early in 

 the morning, efpecially in the higher parts of the country ; and 

 furely the making of ice in Bengal juftifies that obfervation. 



g. THE formation of hail is evidently upon the fame principle 

 as that of fnow. The one is, therefore, equally with the other, 

 explained by the theory. There are, however, peculiarities in 

 the production of hail, which do not take place in that of fnow j 

 but thefe peculiar circumftances are to us, perhaps, unknown ; 

 and as there is nothing in the appearance of hail that is, in any 

 refpect, inconfiftent with the theory, the confounding of fnow 

 and hail brings no error into our fcience, nor affects the doc- 

 trine with the leaft uncertainty. Hail is evidently formed by 

 the collection of fmaller molecules^ which ultimately are of the 



nature 



