

344 Mr. Watt’s Thoughts on the confti tuent : 
certain that this quantity was deftroyed, becaufe fome portio 
of the glafs of the retort was diffolved by the nitre, and fome 
part of the materials employed in making the glafs being alkali, — 
we may conclude, that the alkali of ‘the nitre | | 
mented by the alkali of that part of the glafs-it haddiffélved. ~ 
As the glafs cracked into {mall pieces on Cooling, and fome part. ] 
of the coating’ adhered firmly to it, the auadtte of the glafs 
that was diffolved could not be afcertained. From this experi= . 
ment it appears, that if any of the acid of the nitre enters into 
the compofition of the dephlogifticated air, it is a very fmall parts 
and it rather feems, that the acid, or part of it, unites itfelf fo 
firmly to. the phlogifton as to lofe its attraction for water. hoe 
13. * The vitriolic falts alfo yield dephlogifticated air ‘by 
«¢ heat; and in thefe cafes the dephlogifticated air is always 
«attended with a large quantity of vitriolic acid air or ful~ — 
<¢ phureous vapour,” even when the falts ufed are not known — 
to contain any phlogiftic matter. Mr. ScHEELE mentions his , 
having obtained dephlogifticated air from manganefe diffolved — 
in acid of phofphorus, and alfo from the arfenical acid: from. 
whence it appears, that thefe acids, or perhaps any acid which 
can bear a red heat, can concur to the produétion of dephlo- 
gifticated air. dt is neceffary to remark, that no experiments have 
been yet publifbed foewing that dephlogifiucated air can be produced 
Jrom falts formed by the murtiatic acid. ‘Ihe acids which produce” 
falts fuitable for this purpofe, bave all a frong affinity with 
phlogifion; and the marine acid has either a very [mall affinity 
with it, or elfe is already faturated with it, at leaft fo Eb Satu 
rated as not to be able to attract it from the humor. 
14, “ The dephlogifticated air obtained from the pure calees” 
** of metals may be attributed to the calces themfelves, attratt- 
** ing the phlogifton from water which they have imbibed fromy 
4 ‘* thes 
ee et ee Se é 

