prepared from the Lithic or Uric Acid. 29 
ammonia was added to a solution of alum, no perceptible change 
took place immediately ; but after some time the colour of the 
solution disappeared, and a small quantity of a white substance 
separated, which was presumed to he the purpurate of alumina, 
but it was not examined. 
Purpurate of gold. When a solution of the muriate of gold 
is dropped into a solution of the purpurate of ammonia, the co- 
lour becomes yellowish, but no precipitation takes place. Hence, 
this salt may be presumed to be very soluble. 
Purpurate of platina. The muriate of platina changes the 
colour of the purpurate of ammonia to a yellowish scarlet, but 
produces no precipitation. t 
Purpurate of silver. Solutions of the acetate or nitrate of 
silver, dropped into a solution of the purpurate of ammonia, 
produce a deep purple precipitate ; and the water is left nearly 
colourless. Hence the purpurate of silver appears very in- 
soluble. 
Purpurate of mercury. <A solution of the proto-nitrate of 
mercury produces, with the purpurate of ammonia, a beautiful 
reddish purple precipitate, and the water is left nearly colour- 
less. A solution of the oxymuriate of mercury produces at first 
no change; but after some time a copious light rose-coloured 
precipitate occurs, and the solution is left colourless. 
Purpurate of lead. A solution of the nitrate of lead, dropped 
in a solution of the purpurate of ammonia, renders it of a rose 
‘red colour; but no precipitation takes place. 
Purpurate of zinc. A solution of the acetate of zinc pro- 
duces with the purpurate of ammonia a solution and precipitate 
of abeautiful gold yellow colour; and a most brilliant iridescent 
pellicle, in which green and yellow predominate, forms on the 
surface of the solution. 
Purpurate of tin. A solution of the muriate of tin changes 
the purpurate of ammonia to a scarlet; but this rapidly dis- 
appears, and the solution becomes colourless. After a few hours, 
white pearly crystals form in abundance, which is the purpurate 
of tin. 
Purpurate of copper. A solution of the acetate or sulphate of 
copper changes the purpurate of ammonia to a bright yellowish 
greeu colour, but produces no precipitation. 
Purpurate of nickel. The nitrate of nickel imparts to the 
purpurate of ammonia a greenish tinge, but produces no pre- 
cipitation. 
Purpurate of cobalt. The acetate of cobalt changes the co- 
lour of the same salt to a pale scarlet. After some time, reddish 
granular crystals form, which are the purpurate of cobalt. 
Purpurate of iron, A solution of the green sulphate of iron 
changes 
