510 On the Analysis of the 
p- 405) were not satisfactory, On again 
reading his memoir, it occurred to me that 
a more complete decomposition of nitrate of 
baryta would probably be obtained by ex- 
posing it to a sufficient heat, in a state of 
intimate mixture with charcoal; and that the 
‘elements of the nitric acid would be evolved 
in the state of carbonic acid and. nitrogen 
gases, products which admit of being easily 
and exactly separated from each other, 
In my first trials of this process, I failed 
from the employment. of too little charcoal, 
in consequence of which much nitrous acid 
vapour passed over, and:acted upon the mer- 
cury over which the gases were collected. 
After repeating the operation several times, 
with various proportions of the materials, I 
foundthat by using at least 1 part of charcoal 
to 21 ‘of the nitrate of baryta, nitrous acid 
vapour was no longer evolved. In an exe 
periment made with great care, the barytic 
salt was finely pulverised, and exposed fora 
whole day, with surfaces frequently renewed, 
to a temperature of 212° Faht. It was then 
mixed with the powdered charcoal, which 
had been recently ignited in a close vessel, 
to expel any moisture it might contain, and 
which was still hot; and a portion of quartz 
in very small grains, equal in weight to the 
