94 ESSAYS AND OBSERVATIONS 



from a few experiments, to infer a gene- 

 ral conclufion. 



That an eledlive attradlion between 

 air and water mud detain air in water, 

 and water in air, is evident ; and that 

 thefe effedts are owing to that caufe fin- 

 gly, is extremely probable. But, tho' the 

 fame caufe muft produce the afcent of 

 water into air, properly termed evapora- 

 tion; yet I have not faid that it is the on- 

 ly caufe. Evaporation frequently hap- 

 pens in certain circumflances that rejeft 

 this caufe ; witnefs the great quantity of 

 vapour that afcends from boiling water, 

 far beyond the power of this caufe. 



With refpedt to the afcent of vapour, 

 we have the caufe explained to us by 

 Sir Ifaac Newton. In the 3 1 ft query an- 

 nexed to his optics, we read, that many 

 bodies, which at a fmall diftance have a 

 mutual atcra'iiion, repel each other at a 

 greater diftance. His words are : " And 

 *' this fesms to be evident from the pro- 

 " dudion of vapour. The particles flia- 

 " ken oif trom bodies by heat or fermen- 

 *' tation, are no fooner beyond the reach 



"of 



