33 2 
Mr. Hatchett's Analysis of 
To corroborate this assertion, it will be proper to consider 
the effects of muriatic acid on that of molybdsena, especially as 
the affinity between the radical principle, or base of the mu- 
riatic acid, and oxygen is known to be so great, that no 
chemist has as yet been able to effect a separation of the con- 
stituent principles. 
It has been mentioned, that molybdic acid when dissolved 
in muriatic acid also parts with some oxygen, and tinges the 
menstruum with a green colour. But heat does not enable it 
to take back the oxygen, for it augments the effects of the 
muriatic acid, which, when distilled, passes oxygenated into 
the receiver, and the molybdic acid is converted into a bluish- 
grey oxyde * 
These effects clearly prove, that heat in this case acts in- 
versely to what it did when the nitric and sulphuric acids were 
the menstrua. For then the increase of affinity was between 
molybdaena and oxygen, but here it is in favour of the base of 
muriatic acid ; so that by the continuation of heat, the muriatic 
acid carries with it into the receiver a certain portion of oxygen 
which it has taken from the molybdic acid, and the latter is 
left in the state of an oxyde. 
From this it appears that muriatic acid uniformly tends to 
deprive the molybdic acid of a certain quantity of oxygen, 
and that heat produces a contrary effect on this solution to that 
which it did on the one made with sulphuric acid ; and heat 
and cold do not therefore produce a change of colour. 
I do not, however, believe that muriatic acid acts thus con- 
stantly on all of those metals which can be dissolved by it ; on 
the contrary, there is a muriatic solution which much re- 
* Elemens d’Hist. Nat. et de Cbimie, par M. de F-Ourcroy, Tome II. p. 439. 
