of native iron found in Brasil. 283 
Having filed from my specimen as much as I judged sufficient 
for my purpose, (which need not exceed of a grain), I 
dissolved it in a drop of nitric acid, and then evaporated the 
solution to dryness. A drop or two of pure ammonia was 
then added to the dried residuum, and gently warmed upon 
it in order to dissolve any nickel that might be present. The 
transparent part of the fluid was then led by the end of a rod 
of glass to a small distance from the remaining oxide of iron, 
and the addition of triple prussiate of potash immediately de- 
tected the presence of nickel by the appearance of a milky 
cloud, which was not discernible by the same means from a 
similar quantity of common wrought iron tried at the same 
time. 
For the determination of the quantity of nickel I employed 
a different method. A piece of the iron weighing 50 grains 
having been dissolved in nitro-muriatic acid, the solution was 
evaporated to dryness. Ammonia was then added, and the 
solution again evaporated to dryness, in order that the oxide 
of iron might be rendered more dense, and more easily sepa- 
rated from the soluble portion. A fresh addition of ammo- 
nia then readily dissolved the nickel, and the solution after 
filtration appeared of a deep blue colour. 
A small quantity of sulphuric acid having then been added, 
the whole was again evaporated not merely to dryness, but 
with sufficient heat to expel the excess of ammonia, muriate 
of ammonia, and sulphate of ammonia. The remainder was 
sulphate of nickel which was then redissolved in water, and 
after being suffered to crystallize weighed 8,6 grains. Hav- 
ing found by experiment previously made for that purpose, 
MDCCCXVI. P P 
