t; the tool being covered with a mixture of sand and water; they are then roughened into shape in the rouge and beeswax, the amount of rouge being sufficient to chuck upon one end of a hollow lathe mandrel; near the machine shown in one of the upper views in the large en- render the beeswax quite… … cemented with pitch. In the forced upward against the Fig. 2.—CENTERING LENSES. edge of the lens by means of center of this hub there is a a screw passing through a conical hole of sufficient depth and size to receive the point that projects from the lever board that supports it. The sheet iron is…
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