47 
used in a process called galvanising, which consists of coating sheets of iron with 
a thin coat of this metal, which protects the iron from rusting. It is also used in 
the manufacture of brass, which is an alloy of one part zinc to two of copper. 
Muntz’s metal, used for sheathing ships, is three parts copper to two of zinc with 
a small quantity of lead. Pinchbeck, three parts copper to one of zinc. Dutch or 
Mannheim gold. Tombac, and Aich’s metal are varieties of brass. Zinc does not 
occur in nature in the native state, but most commonly as a sulphide or carbonate. 
Sphalerite or Blende. —Sulphide of Zinc (Black Jack of lead miners). _ 
The colour of this ore varies a great deal from waxy yellow to black, sometimes 
green, red, and white, whilst the streak is white to reddish brown. Its lustre is 
resinous and brilliant. Its hardness is 3*5, and specific gravity 4, and its composi¬ 
tion is sulphur 33, zinc 67. It occurs in this colony, associated with the galena, at 
Northampton aud Cardup, along the Darling Range. 
Tin. 
Symbol , Sn. ( Stannum ) ; atomic weight , 118 ; specific gravity , 7‘29. 
This metal, although met with in but few localities, has been known and 
worked from the earliest times. It is of *a silver-white colour, with a brilliant 
lustre. When heated it emits a peculiar smell, and when bent gives out a 
crackling sound. It is very malleable. Tinfoil may be obtained in leaves less 
than -iff of a millimetre in thickness, but it is not ductile. It melts at a tem¬ 
perature of 442° F., and boils at a white heat, giving off fumes. At ordinary 
temperature it is very little affected by exposure to the air, but in time becomes 
coated with a dark-brown oxide. It occurs in nature in two forms, as an oxide and 
a sulphide, the former of which is by far the most frequently met with. 
Cassiterite. — Tin Ore; Tin Oxide; Stream Tin.—This occurs crystalline and 
massive and in grains. It is of a brown or black colour, with a high lustre, its 
streak being a pale grey or brownish. 
Its hardness is from 6 to 7; specific gravity is also from 6 to 7, whilst its 
composite is oxygen, 21*33; tin, 78*67. 
It resembles garnets, titanic iron, zinc blende, and tourmaline, but is dis¬ 
tinguished by its infusibility when alone, and by its yielding a globule of tin 
when fused with soda. 
This ore occurs both in alluvial deposits as stream tin and in lodes. 
Tin is one of the metals which at the present time is in the greatest demand, 
owing to the discovery of a process by which sheets of iron can be coated with it, 
which protects the iron from oxidation or from being attacked by acids when 
used in canning goods. The tin used in this way is completely lost as far as 
things can be in nature, for it has been found quite impossible to utilise the 
recovered tin from old cans owing to the presence of lead in the solder. 
Tin is also used to form alloys, 10 per cent, of it with copper being gun metal. 
Three parts of copper and one of tin form bell metal; one part tin and two parts 
copper, speculum metal. Bronzes are various mixtures of copper, tin, zinc, lead, 
and iron, the bronze used for coinage containing 95 parts copper, 4 tin, and 1 zinc. 
Solder, pewter, and Britannia metal are alloys of tin, copper, zinc, antimony, 
bismuth, and lead. 
Mercury readily dissolves tin, the amalgam being used to cover glass in the 
manufacture of mirrors. 
Tin ore is found in this colony at the Greenbushes Tinfield, and on the Shaw 
River to the Eastward of Roebourne, whilst small samples are reported to have 
been found in several places in the Darling Range, 
