1819.] History of Anthrazothionie Acid. 47 
both opinions appear equally valid ; while the former, from the 
reason stated, and from the properties of the metallic anthrazo- 
thionhydrates, seems to me much more likely to be the true one. 
Sect. 12. Properties of some metallic Anthraxothionhydrates. 
—a. That of silver is white, curdy, and very voluminous ; it has 
some resemblance to muriate of silver, and becomes black by 
exposure to the atmosphere, at least if it has been treated with 
ammonia and well washed; but it does not become so black as 
muriate of silver ; from which it is very easily distinguished, as 
itis not soluble in ammonia. In this respect it resembles iodide 
of silver, with which, however, it cannot be compared in its 
other properties. Liquid chlorine forms with it muriate of 
silver, sulphur is precipitated, ammonia formed, and carbonic 
acid gas evolved. Chlorine produces the same effect upon all 
the other metallic anthrazothionhydrates. 
b. The anthrazothionhydrate of gold is capable of assuming 
different colours, according to the way that it is prepared. 
When treated with muriatic acid and water, it becomes gra- 
dually of a dark purple colour. When the dark precipitate is 
put into a concentrated solution of anthrazothionate of potash, it 
assumes a light flesh colour, doubtless because it enters into 
combination with a little of the anthrazothionate of potash. 
Should not the analogy of the formation of white prussiate of 
iron be attended to here? When the flesh coloured substance is 
put into muriatic acid, it becomes dark purple. Potash deprives 
it of a part of its anthrazothion, and gives it a yellow colour. The 
precipitate when first formed, and even after being dried, is 
very voluminous. The anthrazothionide of gold is soluble in 
liquid anthrazothionate of potash, and the solution has a dark 
red colour. I added an excess of anthrazothionate of potash to 
a neutral solution of gold in muriatic acid, and then filtered the 
liquid ; it passed through the filter dark red. Some drops of 
ammonia threw down a black powder from this liquid, and the 
dark red colour disappeared, 
c. The anthrazothionhydrate of mercury is white and bulky, 
and is formed by double decomposition only when the metal is 
in solution in an acid in the state of protoxide. ‘The solution of 
corrosive sublimate is not precipitated by anthrazothionate of 
potash; but if apiece of tin be putinto the mixture, the anthra- 
zothionhydrate of mercury is precipitated mixed with metallic 
mercury. It would seem that when the metal of an anthrazo- 
thionhydrate contains more oxygen than the hydrogen of the 
acid is capable of taking up, and when in this state it is in 
solution in an acid, it is capable of forming with anthrazothionic 
acid by means of double decomposition a soluble anthraxothion- 
ate, but not an el raatbenk irae. 
d, The anthrazothionhydrate of platinum is yellowish, bulky, 
and easily soluble both in acids and in liquid munates. From 
