Miller, Kempster Blanchard, 1870-1933 · New York : McGraw publishing company · leaf 61
als would discolor and roughen with .use, thus spoil-ing their appearance and rendering them unpleasant to the touch. Recent improvements in these materials have been made, how-ever, which seem to justify the hope that a material as good as hardrubber may be found. Composition shells are again… … FIG. 25.-ADER BIPOLAR RECfelVER, moisture. Moreover, the improved material does not seem topossess the objectionable softening and changing under heat andpressure to as great an extent as hard rubbjer. A way of obviating the expansion and contraction difhculty usedlargely in European countries and…
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