the Carinthian Molybdate of Lead. 313 
white precipitate was the same neutral salt which I obtained 
in several other operations, and which has also been noticed 
by Scheele and Klaproth.* 
I now began to examine the blue solution B, which con- 
sisted of the sulphuric solution of molybdic acid, saturated 
with ammoniac ; but that the experiments made on this may 
be better understood, I shall first give an account of some ex- 
periments and observations which I have made on the sul- 
phate of ammoniac. 
Experiments and Observations on the Sulphate of Ammoniac. 
This neutral salt, which from Glauber (who first pre- 
pared it) was called the secret ammoniacal salt of Glauber, 
or vitriolic ammoniac, has been very little examined ; neither 
has it been applied to any useful purpose, although the in- 
ventor much recommended it in metallurgical operations. 
It has been long known that the fixed alkalies, lime, and 
barytes (when triturated with it), decompose it, by uniting 
with the acid. But the effects of heat on it do not appear to 
have been sufficiently observed. 
Macquer says, that it is (to use his expression) demi- 
volatile, that it may be sublimed entire, and that it cannot be 
decomposed in close vessels without some intermediate sub- 
stance/f 
Baume' makes use of nearly the same expressions. J 
* Scheele observes, when molybdsena was detonated with nitre, and the mass af- 
terwards dissolved in water, and saturated with sulphuric, nitric, or muriatic acid, that 
a white precipitate was produced, which was the acid of molybdsena combined with a 
portion of alkali. Essays, p. 231, and 240. 
-f- Dictionnaire de Chimie, Tom. I. p. m. 
J Chimie Experimental et Raisonnee, Tom. II. p. 83. 
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