OPE. ocular lens. are brought to the machine in a red hot state, and the fish BY DR. L. HILLE, Sun spots and solar protuberances were formerly observed with instruments called sun glasses, which were made of double glasses, the intermediate space being filled with light- The machine, shown in the… … ward stroke, the finished fish plate remains on but it becomes more and more faint when the the machine until the foot lever, A, is released, upper mirror is turned, until ata right angle THE HELIOSCOPE. it disappears altogether, so that the field of when the stop, B, is moved out of the way, and…
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