96 ESSAYS ANT? OBSERVATTONS 



" fame repelling power it feems to be, 

 *' that flies walk upon water without wet- 

 •* ting their feet," &c. 



Here is good authority, that an elec- 

 tive repulficn is the caufe of vapour. 

 But, to give all the light poffible to an 

 obfcure fubjedl, fome additional obferva- 

 tions may be proper with refpecfl to an e- 

 le(5live attraction being converted by 

 change of circumftances into an eledlive 

 repulficn. It appears from experiments 

 made by Doctor Hale in his vegetable 

 ftaties, that, of every vegetable, air makes 

 a component part; that, particularly, air 

 tnakes the third part of the weight of a 

 green pea ; a quantity that, in the natu^ 

 ral ftate of air, would occupy many cu- 

 bic feet. It is a known property of air, 

 that its particles have a mutual repulfionr; 

 and there muft be a vigorous .eledive at- 

 tradlion between air and the fubftance of 

 a vegetable, to condenfe the former fo 

 much within the latter. This eledive 

 attraction is by heat converted into an e- 

 ledive repulfioH, which, when greenwood 



is 



