specific gravity, and acting a powerful fluxes. The Compound Glasses
are as follow—viz.,
Highly pellucid and transparent Flint Glass
|Carbonate of Potash
|Red Lead or Litharge
|Sand washed and burnt
||lbs. to 28 lbs.
|Oxide of Manganese
||oz. to 12 oz.
These materials, mixed together, are
technically called batch; and when fused, are termed metal.
Soft White Enamel (Opaque.)—To
6 cwt. of batch, add 24 lbs. of arsenic, 6 lbs. of antimony.
Hard White Enamel (Opaque.)—To
6 cwt. of batch, as above, add 200 lbs. of putty, prepared from tin and
Blue Transparent Glass.—The
above 6 cwt. of batch, coloured with 2 lbs. of oxide of cobalt.
above 6 cwt. of batch, with about 6 lbs. of oxide of copper.
above 6 cwt. of batch, with about 4 oz. of oxide of gold.
Amethyst or Purple.—The
above 6 cwt. of batch, with about 20 lbs. of oxide of manganese.
6 cwt. of batch, add 12 lbs. of iron ore, and 4 lbs. of manganese.
6 cwt. of batch, add 12 lbs. of copper scales, and 12 lbs. of iron ore.
Gold Topaz Colour.—The above
6 cwt. of batch with 3 lbs. of oxide of uranium.
A beautiful blue may be produced from nickle,
but cobalt is generally preferred; the latter, for casing, should be