The optical lantern, for instruction and amusement (1890)
Pringle, Andrew · New York, The Scovill & Adams Company · leaf 59
THE OPTICAL LANTERN. 49 The body is conical in section, made of wrought iron, brazed and riveted. The neck screws on to the body and a washer of mill-board or felt impregnated with asbestos is placed between body and neck. Sometimes the bottom is made of copper, this costs more and is unnecessary.… … Fig. 27. top may be seen a small cylindrical projection ; in this is placed pretty tightly a cork, and so a safety-valve is obtained. If any stricture occur in the gas-way the cork will be blown out. The neck of a retort should never have a square turn, but always be rounded, as in Fig. 27. No…
Lantern projection
Internet Archive · Smithsonian Libraries · Public domain (published before 1931). Free to use for anything.
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