834 ' Transactions. —Chemistry. 
wire; but afterwards, for greater certainty in the matter, I employed silver 
most carefully prepared, and by approved processes for pure silver. As 
electro-plated upon lengths of surgical wire, it is most easily worked, 
and, being thus in a spongy form, its behaviour with the mereury test can 
be minutely and readily observed. It is necessary, of course, to well wash 
this silver from alkaline cyanide by distilled water before using it in these 
experiments. I should inform you I could not observe that sun-light 
exerted an effect in any of these reactions, whether accelerating or retarding. 
In regard now to the metal platinum, I ascertained that it is also passed 
to a condition in which it will not amalgamate, by giving it contact for a 
short time with distilled or ammoniated water, also with aqueous solutions 
of the alkalies, their carbonates or chlorides, while acids generally put it 
quickly back into an amalgamable condition; an elevation of its tempera- 
ture to about 400° F. will also accomplish this. 
Platinum also generates electric currents when paired with graphite in 
saline or alkaline solutions, 
These facts, I think, show undeniably that platinum not only absorbs 
oxygen, as is already known, but that this absorption is, in the cases cited, 
a chemical one, an oxide or a suboxide of this metal being formed. That 
in the so-termed mechanical absorption of certain gases by platinum, 
platinic compounds are produced, is an idea which I have long since 
entertained.* 
In conclusion, I would beg to inform you that, from a partial investi- 
gation of the behaviour of gold in certain liquids, I believe this metal is 
also oxidizable under conditions somewhat similar to those under which I 
- have stated silver to be, but the results of this investigation I will endeavour 
to communicate at our next meeting. 
Arr, XLITI.—On the electro-motive order of certain Metals in Cyanide of 
Potassium, with reference to the use of this salt in Milling Gold. By 
Wit Sxey, Analyst to the Geological Survey of New Zealand. 
[Read before the Wellington Philosophical Society, 29th January, 1876.] 
Waite on an official visit at the Thames Goldfield I had many opportuni- 
ties for observing the marked effect of Cyanide of Potassium, in preventing 
the flouring of mercury used in working off the blanketings. These 
blanketings I found have as a rule, a decidedly acid reaction, due in a 
greater part to the presence of ferric and ferrous salts soluble in water, and 
it is to the former of these salts, that what is commonly known as 
* “Trans. N. Z. Inst.,” Vol. Iit., Art. XXX VIO, 
bes 
