152 Remarks on Priestley’s Analysis 
found the means of analysing this substance, we are 
able to shew its composition by synthesis ; and this 
method is at least as decisive as the analytical. Sup- 
' posing we were unacquainted with the means of de- 
composing any neutral salt, for example, Glauber’s 
salt, there would be hardly any one so incorrigibly a 
sceptic, as to doubt that it is composed of sulphuric 
acid and soda, if by combining these substances we 
produced that salt. This is exactly the case with 
finery cinder. We have seen (by the fine experi- 
ments made by Dr. Priestley, with iron heated in 
oxygenous gas, of which I gave an abstract in the 
former part of this paper) that the oxygen combined 
with the iron, and produced a calciform substance ; 
which he found, by various experiments, to be the 
same thing with finery cinder. The conclusion is 
obvious: finery cinder is iron combined with oxy- 
gen. But as Dr. Priestley believes, that it is only 
water that has combined with the iron; because wa- 
ter, as he maintains, is by far the greatest part of 
oxygenous gas, it will be proper to examine into the 
truth of this opinion, particularly as his whole theory 
must stand or fall with it—The experiments on 
which this opinion rests, are to be found in his 1st 
vol. of Experiments on Air, p. 130—132.* Not 
being able to expel the carbonic acid from éerra 
* I know of no other experiments.on which this philo- 
sopher grounds this opinion, 
