ed, and heated to a red heat.
Graphite may also be purified sufficiently for most uses by treating it with 4 parts sulphuric and 1 part nitric acid, washing and drying.
See crucible; pencil.
These points are taken from the manuscript of a work on graphite, now in course of preparation, by Orestes Cleveland, President of the Dixon Crucible Company, of Jersey City.
A surveying instrument for taking angles.
A process invented by Hitchcock, in which a zinc plate is covered with a thick coating of oxide of zinc, placed under an hydraulic press to made a perfectly plain and hard surface, the design drawn upon the oxide with an ink consisting of a chloride of zinc and a menstruum.
This produces as to the parts where the ink touches a very hard material, the oxychloride of zinc.
The remaining surface is rubbed away by brushes, velvet, and the fingers, leaving the lines in relief to be printed from.
The process is more used
but it is understood that Krupp of Essen is now building one to work a mass of steel of 100 tons (of 2,240 lbs.)
Alonzo Hitchcock's cannon-forging steam-hammer and furnace. weight, and which is expected to cost $1,000,000. The weight of the falds, and cost $92,000, and is said to be the largest in the United States.
Plate LXIII illustrates the system of Mr. Alonzo Hitchcock, of New York, for forging cannon, hollow shafting, hydraulic cylinders, and other large masses of iron, particularking-beams.
See also Fig. 3054.
A mill for grinding stone or ore. See ore-crusher; ore-mill.
Hitchcock's quartz-crusher (Fig. 5849) is on the principle of the Chilian mill, but has three wheels instead of two, traveling arls of this class, adding greatly to the crushing force, which may be developed by the application of an equal power.
A machine for working a face on a stone or ashlar; in other words, a machine fo