2 14 Experiments on the Production of Air 



of the water changed to a dead yellowish cast, and the 

 cotton assumed the same hue. 



The following are the quantities and qualities of the 

 different parcels of air furnished in the course of this 

 experiment. 



Quantity. Quality. 



Upon the loth of June \\ cubic inches \ a A^ i» = 1.65, or 35 

 nth, i2th, and 13th i ... \a -\- xn ^=. 2.00, or o 



Total quantity 44^ Mean qual. 



^ + 3« = 1.43, or 257 



a ^ in =. 1.34, or 266 



^ -j- 4 ;? = 1.40, or 360 



a Ar An z= 1.44, or 356 



^ "~1~ 3'^ = 1.06, or 294 



a -\- zn 



1.23, or 277 



This experiment was repeated, and with nearly the 

 same result; the total quantity of air produced being 

 41^^ cubic inches, and its quality, at a medium, \ aA^^'^ 

 = 1.26, or 274. 



To ascertain the relative fineness of this poplar cotton 

 and the thread of raw silk as spun by the worm, in order 

 to make an estimate of the surface of the former, 1 ex- 

 amined them both at the same time under an excellent 

 microscope, when the diameter of the cotton, that is to 

 say, of a single thread or fibre of it, appeared to be not 

 more than half as great as the diameter of the silk, con- 

 sequently its diameter was not more than 3 g jg- part of 

 an inch ; for I have found by experiment that the diam- 

 eter of a thread of silk, as spun by the worm, is only 



TsVt °^ ^""^ inch. 



The specific gravity of the cotton I found to be very 

 nearly equal to that of water, consequently it is to that 

 of silk as 1000 to 1734 ; its surface, therefore, is to the 

 surface of an equal weight of raw silk in the compound 



