650 
ME. EDWARD MATTHEY ON THE LIQUATION 
necessary to ensure accuracy, as in practice it is found impossible to obtain the whole 
of the constituent metals from these alloys within y§^th s P er cent. 
I tried other known processes for these determinations, but none gave such 
accurate results ; and in this view I am confirmed by Mr. W. Bettel whose paper in 
the £ Chemical News,’vol. 56, No. 1452, shows that he has devoted much patient 
attention to the subject. 
The method of analysis adopted in the case of the alloys of gold 900 and 
palladium 100 parts, consisted in removing the palladium by the process of 
“ quartation ” with fine silver. Carefully weighed portions of the alloys under 
examination were cupelled in pure lead with two-and-three-quarter times their 
weight of fine silver. Each cupelled button so produced was then laminated, 
annealed, and treated with and “ parted ” by boiling in nitric acid three distinct 
times. By these means the palladium is dissolved out as well as the silver, the gold 
being left. The resulting gold, after being washed and annealed, was again cupelled in 
lead with a further proportion of two-and-three-quarter times its weight of fine silver, 
and again parted by boiling in nitric acid three distinct times, to ensure the removal of 
the whole of the palladium, the gold so obtained after being washed, annealed, and 
weighed, yielding the percentage of pure gold in the alloy. The proportion of 
palladium was then found by the difference 
To ensure accuracy, checks or standards, made up of pure gold 900 parts and palla¬ 
dium 100 parts, were worked side by side with all the analyses made. 
All the results by this process are trustworthy and accurate. 
The process adopted for the determinations of the platinum and palladium in the 
series of alloys made of these metals was as follows :— 
Of each portion of the alloy to be analysed, accurately weighed portions of 50 
grains each were attacked by nitrohydrochloric acid, which gradually dissolved the 
whole of the alloy under digestion. The resulting chlorides were then carefully 
evaporated nearly to dryness, then re-acidified with hydrochloric acid, and again 
evaporated almost to dryness. These re-evaporated chlorides were then dissolved 
in distilled water, and the respective solutions of each analysis were diluted to a 
volume of about 5 ounces, and allowed to become quite cold. 
Cyanide of mercury was then added in slight excess to precipitate the palladium, 
and the whole allowed to remain for twenty-four hours in a warm atmosphere, 
experience showing that this precipitate of palladium cyanide comes down better 
under these circumstances. At the end of tnis time the precipitate of palladium 
cyanide was collected on filters, washed, dried, ignited, and weighed as pure palla¬ 
dium. 
The whole contents of the palladium in the alloys is precipitated by these means. 
To obtain the platinum from the mother liquors, from which the palladium had 
been removed, they were evaporated to a capacity of about 30 cub. centim. Ammonium 
chloride was then added, and the platinum precipitated as the double salt of platinum- 
