Olmsted, Denison, 1791-1859. [from old catalog] · New York, R. B. Collins · leaf 69
88. How is an image formed by a concave mirror 1 How isthis image magnified 1 When is the instrument called a re-fracting and when a reflecting telescope I For what pur-poses are telescopes chiefly employed ? 56 THE EARTH. 89. The Transit Instrument is a telescope, which isfixed permanently in the… … TV on two firm supports, as pillars of stone, for example, soconnected with the building as to be as free as possiblefrom all agitation. In figure 12, AD represents the tele- 89. What is a Transit Instrument ? On what supports doesit rest as represented in figure 12. Why are they made so…
Astronomy
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