of Gold and other Metals to Light. 513 
the ruby fluid is formed, but it soon becomes turbid and tends 
to produce a deposit. When the gold is in such proportion that 
it remains in considerable excess, still the ruby formation is not 
prevented, and being formed, it mingles unchanged with the 
excess of gold in solution. If an exceedingly weak solution of 
gold be employed, the production of ruby appears to be imper- 
fect and retarded. The nearer the solution is to neutrality at 
the commencement the better; when a little hydrochloric acid 
was added, the effect was not so good, and the colour of the fluid 
was more violet than ruby. 
If a pint or two of the weak solution of gold before described 
be put into a very clean glass bottle, a drop of the solution of 
phosphorus in sulphide of carbon added, and the whole well 
shaken together, it immediately changes in appearance, becomes 
red, and being left for six or twelve hours, forms the ruby fluid 
required ; too much sulphide and phosphorus should not be 
added, for the reduced gold then tends to clot about the portions 
which sink to the bottom. 
Though the sulphide of carbon is present in such processes 
and very useful in giving division to the phosphorus, still it is 
not essential. A piece of clean phosphorus in a bottle of the 
gold solution gradually produces the ruby fluid at the bottom, 
but the action is very slow. If the phosphorus be attached to 
the side of the bottle, but always beneath the surface of the 
solution, the streams of ruby fluid may be seen moving both 
upwards and downwards against the side of the glass, and form- 
ing films in the vicinity of the phosphorus perfect in their golden 
reflexion, and yet transmitting light of ruby, violet, and other 
tints, thus giving, first a proof that the particles are gold, and 
then connecting the present condition of the gold with that of 
the films already described. On the other hand, the phosphorus 
may be excluded and the sulphide of carbon employed alone ; 
for when it and the solution of gold are shaken together, the 
gold is reduced and the ruby fluid formed ; but it soon changes 
to purple or violet. 
A quick and ready mode of producing the ruby fluid, is to 
put a quart of the weak solution of gold (containing about 0-6 
of a grain of metal) into a clean bottle, to add a little solution 
of phosphorus in ther, and then to shake it well for a few mo- 
ments: a beautiful ruby or amethystine fluid is immediately 
produced, which will increase in depth of tint by a little time. 
Generally, however, the preparations made with phosphorus dis- 
solved in sulphide of carbon, are more ruby than those where 
ther is the phosphorus solvent. The process of reduction 
appears to consist in a transfer of the chlorine from the gold to 
the phosphorus, and the formation of phosphoric or phosphorus 
Phil. Mag. 8. 4. No. 96. Suppl. Vol. 14. 2 L 
