DOI Page / Citation link:
https://doi.org/10.11588/diglit.42779#0319
APPENDIXES
I. EMERY
I am indebted to Messrs. Harrison Brothers, Ltd., of Middlesbrough,
for the following information about emery and artificial abrasive.
Emery is an impure form of corundum. It is to-day obtained from
Naxos, from the basins of the Sarabat and Mender rivers in Asia
Minor and from the region of Chester, Mass, and Peekskill in the
United States of America. Emery is a unique mineral, as it is a
mixture of alumina oxide and iron as magnetite and haematite.
Corundum theoretically contains but two elements, alumina and
oxygen, its chemical formula being A1203. Commercial corundum
generally contains a trace of silica, ferric oxide, and combined water.
As found in a mine it is not in a pure state and is mixed with other
minerals such as felspar, hornblende, margaritite, muscovite, &c. It
is largely found in the United States and in Ontario, Canada as block
corundum, crystal corundum, and sand corundum. It occurs usually
in igneous rocks, principally syenites and in several gneisses and
schists. Canadian corundum occurs in nepheline syenite associated
with Laurentian gneiss.
Artificial corundum is produced by the fusion of lead oxide and
alumina in a fire-clay crucible, so forming lead aluminate. Silica
enters into the composition of fire clay and, under the influence of
high temperature, the silica of the crucible gradually decomposes the
lead aluminate, forming lead silicate which remains in a liquid state
while the alumina crystallizes as white sapphire. By mixing a small
amount of chromium, rubies have been formed.
A German scientist changed natural emery into iron-and-water-free
corundum by the mixture and fusion with charcoal or coke.
Carborundum is the trade name for carbide of silicon, which is a
chemical combination of the two elements carbon and silicon. The
material was first made by Edward G. Acheson in 1891 when he
discovered a few bright crystals surrounding the carbon electrode in
an iron bowl in which he had fused by means of an electric current
a mixture containing carbon and silicon. Coke and silica sand, which
supply carbon and silicon, are the raw materials which enter into the
manufacture of this remarkable abrasive.
Aloxite is an abrasive, artificially made, used for grinding steel
I. EMERY
I am indebted to Messrs. Harrison Brothers, Ltd., of Middlesbrough,
for the following information about emery and artificial abrasive.
Emery is an impure form of corundum. It is to-day obtained from
Naxos, from the basins of the Sarabat and Mender rivers in Asia
Minor and from the region of Chester, Mass, and Peekskill in the
United States of America. Emery is a unique mineral, as it is a
mixture of alumina oxide and iron as magnetite and haematite.
Corundum theoretically contains but two elements, alumina and
oxygen, its chemical formula being A1203. Commercial corundum
generally contains a trace of silica, ferric oxide, and combined water.
As found in a mine it is not in a pure state and is mixed with other
minerals such as felspar, hornblende, margaritite, muscovite, &c. It
is largely found in the United States and in Ontario, Canada as block
corundum, crystal corundum, and sand corundum. It occurs usually
in igneous rocks, principally syenites and in several gneisses and
schists. Canadian corundum occurs in nepheline syenite associated
with Laurentian gneiss.
Artificial corundum is produced by the fusion of lead oxide and
alumina in a fire-clay crucible, so forming lead aluminate. Silica
enters into the composition of fire clay and, under the influence of
high temperature, the silica of the crucible gradually decomposes the
lead aluminate, forming lead silicate which remains in a liquid state
while the alumina crystallizes as white sapphire. By mixing a small
amount of chromium, rubies have been formed.
A German scientist changed natural emery into iron-and-water-free
corundum by the mixture and fusion with charcoal or coke.
Carborundum is the trade name for carbide of silicon, which is a
chemical combination of the two elements carbon and silicon. The
material was first made by Edward G. Acheson in 1891 when he
discovered a few bright crystals surrounding the carbon electrode in
an iron bowl in which he had fused by means of an electric current
a mixture containing carbon and silicon. Coke and silica sand, which
supply carbon and silicon, are the raw materials which enter into the
manufacture of this remarkable abrasive.
Aloxite is an abrasive, artificially made, used for grinding steel