e 
324 A. LIVERSIDGE. 
blackened, and a black powder came away on rubbing with the 
finger, but some permanent brown coloured gold was left on the 
foil. The foil increased -0060 g. in weight in fifty-nine days. 
A certain amount of loose gold was thrown down with some: 
of the minerals, but no account was taken of this, as the chief 
object was to ascertain whether a nucleus of gold would have a 
coherent film of gold deposited upon it when the nucleus formed 
one element of a couple, and this was found to be the case—the 
deposit of gold on the foil was usually of a dull reddish-brown 
colour, felt rough to the nail, and under the microscope was seen 
to be mammillated, and when rubbed with a hard substance like 
agate or a glass rod, presented a series of bright points. 
Experiment 17, with iron pyrites.—Part of an uncrystallised 
mass. The coating of gold was dull, with here and there a bright 
speck, something like the hexagonal plates on the copper pyrites ; 
but the outlines rather irregular; bright gold also along the cracks 
in the pyrites. The deposit on the plate was of a full copper colour, 
very rough, and weighed 0708 g. 
Experiment 18, with iron pyrites.—Part of a pentagonal 
dodecahedron, acquired a dull brown deposit of gold, but no 
crystals were detected. A similar brown film on the plate in- 
creased ‘0633 g. in weight. 
Experiment 19, with rhombic iron pyrites or Marcasite.-— 
Became coated with dull brown gold which gave it the appear- 
ance of a coating of rust, there were a few bright specks but no. 
distinct crystals of gold. The gold plates acquired a bronze colour, 
with a greenish shade, became rough and increased ‘0328 g. in 
weight. 
Experiment 20, with brown hematite.—Decolourised several ' 
charges. Foil became dull and increased ‘0003 g. weight in fifty- 
nine days. 
Experiment 21, with limonite.-—Decolourised seven ounces. 
of the gold solution. Foil became dull and increased -00025 g. in 
weight in fifty-nine days. The deposited gold was dull and mam- 
millated. 
