Howe, Herbert A. (Herbert Alonzo), 1858-1926 · Meadville, Penna., Flood and Vincent · leaf 141
A forty-inchdisc. 134 A Study of the Sky. Bubbles. Striae. … Internal strain. the disc must be reheated and molded again, but if toomany annealings are attempted, the glass may lose itstransparency. After months of labor the original shape- less mass is re-duced to a beauti-ful circular disc. A few small bub-bles, or bits of grit,while they mar theappearance…
Astronomy
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