tvi Mr. kirwan’s Experiments and Obfervatkns on 
as (liver lofes a certain quantity of phlogifton, which efcapes 
and feparatefe from it during its folution in nitrous acid, I con- 
ceived, that if the folution was expofed to nothing from which 
it could re-obtain phlogifton, and thus diftilled to drynels, and 
intirelv feparated from the acid, as much filver (hould remain 
unreduced as correfponded with the quantity of phlogifton loft by 
it. And if this quantity of phlogifton correfponded with that 
aftigned to filver in the foregoing table, that then this table was 
juft. 
For this purpofe I diffolved 120 grs. of clean filings of 
ftandard filver in dilute dephlogifticated nitrous acid, and 
obtained from it 24 cubic inches of nitrous air. This 
folution 1 gently evaporated to drynefs ; by the evaporation I 
found a little of the filver volatilized, but not more than a 
quarter of a grain. 1 then diftilled the dry refiduum, and kept 
v 
it an hour in almoft a white heat in a coated green glafs retort. 
During the diftillation abundance of the nitrous acid palled off, 
■a screen and white fublimate arofe in the neck of the retort, 
•and l'ome palled even into the receiver. When all was cold 
1 broke the retort, the infide of which was penetrated 
into its very fubftance with a yellow and red tinge, and partly 
covered over with an exceeding fine filver powder, which 
could fcarcely be (craped off. The remainder of the filver was 
perfectly white and free from acid, but not melted into a but- 
ton, and when collected weighed 94 grs. ; therefore 26 grs. 
were loft, that is, were iubiimed or vitrified 1 ; but of thele 26 
grs. 9 grs. were copper (for 100 grs. ftandard filver contain y\ 
of copper) '; therefore, only 17 grs. of pure filver remained un- 
reduced, being either volatilized or vitrified. The whole quan- 
tity of pure filver in 120 grs. of ftandard filver amounts to. m 
grs. ; then if 1 1 1 grs. of pure filver lobe 1 7 by rcaion of its 
lofi& 
