Well's natural philosophy : for the use of schools, academies and privte students, introducing the latest results of scientific discovery and research ; arranged with special reference to the practical application of physical science to the arts and the experiences of everyday life ; with three hundred and seventy-five engravings (1873)
Wells, David A · New York : Ivison, Blakeman, Taylor and Co. · leaf 369
is generally moved by clock-work, an4 i^ accurately 364 WELLS S NATURAL PHILOSOPHY. counterbalanced by an arrangement of weights. A small telescope called thofinder, is attached near the eye end of tho large one ; this is so adjusted thatwhen the object is seen through it, it appears in the field… … What is a Spy.glass ? 724, A spy-i^lass, or terrestrial telescope,differs from an astronomical telescope only inan adjustment of lenses, which enables the observer to seethe images of objects erect instead of inverted. This isefiected by the addition of two lenses placed between thoeye and the…
Physics · Science · Technology
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