CHliMlCAL PRINCIPLES. 
351 
exidimi aurosuin is decomposed and converted into metallic Oxidesofgold. 
gold and oxiduin auricnm. 
A portion of murias aurosus, perfectly fre« from any murias 
auricus, was decomposed by boiling water. The metallic gold 
produced was well washed and heated, in order to get rid of 
any moisture. The solution of the murias auricus, formed by 
this decomposition, was precipitated with murias ferrosus, and 
the metallic gold well washed and dried. On examining the 
weight of these two portions of gold, I found that of the for- 
mer to be exactly double that of the latter, which result was 
also confirmed by a careful repetition of the same experiment. 
It follows, therefore, that the oxidum aurosuni contains a quan- 
tity of oxigen sufficient to form oxidum auricum with a third 
part of the gold which it contains. That is to say, the gold in 
the oxide in icum, is combined with three times as much oxi- 
, gen as it is in the oxide in osum. So that the composition 
of the oxidum auricum being known, that of the oxidum auro- 
, sum consequently becomes 
Gold 9(5,13 UX),(X)0 
Oxigen 3,87 4,026 
Here then we have the first instance of a ratio which 
irises suddenly from 1 to 3. And this circumstance seems to 
I prove that gold possesses an intermediate degree of oxidation, 
• incapable of becoming saline, because not formed previously to 
I the oxidule. 
In order to discover the properties of the oxidum aurosum, 
II poured on some newly-prepared murias aurosus, a quantity of 
(caustic alkali. The muriate immediately produced a beautiful 
jgreen colour, and detached a green pow'der, the lightness of 
(which occasioned it to be suspended in the liquor. When the 
iliquor became clear, it was of a green colour, shewing that the 
rexcess of the alkali had dissolved a portion of the oxidule. The 
coxidule thus formed, was of very short duration. In spite 
(of the pains I had taken to place the phial containing it in a 
.dark room, I found that in half an hour this was covered with 
a brilliant crust of gold j and after some hours had elapsed. 
Appendix. Vox.. XXXVI. — No. 170. Dd the 
