io ANALYSISoF 



cupied the fpace of i.oi. Examining the mixture at 

 different times, I obferved that the diniinution kept ad- 

 vancing till fome time before 24th of Auguft, when it oc- 

 cupied the fpace of only 0.545. Another mixture made 

 in the fame manner was 0.54, and another 0.65. At 

 the fame time I found other mixtures made without 

 agitation, which at firft occupied the fpace of 1.25, were 

 in one cafe 0.75, another 0.72 and another 0.65. 



The reafon why I apprehend the diminuton goes on [o 

 long is, that time is requifite for the adlion of the 

 phlogifton in the nitrous air upon the dephlogifticated 

 part of the atmofpherical air, in order to the converfion 

 of the whole of it into nitrous acid, in confequence of 

 this part being intimately diffufed through the phlogif- 

 ticated part, by which it is, as it were, protected from its 

 action, which is fimilar to many other chemical proceffes. 

 It is for the fame reafon that the diminution is much 

 greater with agitation than without it, as the parts dif- 

 pofed to unite are thereby brought into better contaft. 



When atmofpherical air is exploded together with in- 

 flammable air, the diminution never proceeds fo far as 

 when nitrous air is mixed with it ; becaufe in this cafe 

 phlogifticated air, as well as nitrous acid, is formed by 

 their union ; and, as I have fhewn, the greater is the 

 proportion of the inflammable air employed, the greater 

 will be the proportion of phlogifticated air in the re- 

 fiduum. This mixture, however, will go on diminifh- 

 ing for fome time, though not fo far as that with the 

 nitrous air ; becaufe part of this produce being nitrous 

 acid, as I have fliewn in a foriner courfe of experiments, 

 it will require time to be formed, as well as when the 

 nitrous air is employed. 



Having made a mixture of equal parts of inflammable 

 »nd atmofpherical air, and exploded them on the 3d 

 of Augufl:, I obferved that it then occupied the fpace of 



^^3S 



