2io Experiments on the Production of Air 



For safety, therefore, and that I might not by an acci- 

 dent lose the trouble I had already had with it, I put an 

 end to the experiment at the end of the fourth day. 



The water had lost of its transparency, and had ac- 

 quired a greenish cast, as in the last experiment ; and in 

 both these experiments I observed that a considerable 

 quantity of whitish yellowish earth was precipitated from 

 the water, which, falling to the bottom of the globe, at- 

 tached itself to the glass in such a manner that it was 

 with difficulty that it could be removed. These were 

 general appearances, and took place in all cases, in a 

 greater or less degree, where a considerable quantity of 

 pure air was separated from water by the influence of 

 light. 



Experiment No. 15. 



The silk made use of in the last experiment having 

 been frequently used in the foregoing experiments, I was 

 desirous of seeing the effect of making use of fresh silk ; 

 and also of varying the proportion between the quantity 

 of silk, the quantity of water, and the size of the globe ; 

 accordingly at 6 o'clock, p. M., upon the ijth of June, 

 I filled a small globe, about three inches in diameter, or 

 (to ascertain its size more exactly), which contained just 

 20 cubic inches, with fresh spring-water, and 17 grains 

 of raw silk, wound in a -single thread, which had never 

 been put into water, or otherwise used, since it came 

 out of the hands of the silk-winder. 



At the end of four days, viz. the i4th, i5th, i6th, 

 and iyth of June, this globe had only furnished ^ of a 

 cubic inch of air, which, proved with nitrous air, gave 

 i a -f- i n = 1-32, or 68 ; consequently, was much worse 

 than common air. 



Upon the i8th it began to produce good air, and dur- 



