Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon (1908)
Hildebrandt, A. (Alfred), b. 1870, Story, W. H. tr · New York, D. Van Nostrand company · leaf 339
/ is the focal length, then b = —^- • There-in fore if the distance is 100 times the focal length, the size of the object will be 100 times that of the image. In order to get large images of distant objects, it is therefore necessary to use a lens of great focal length. It is often suggested that… … Fig. 198.—Mont Blanc, as seen from Geneva ; ta I &Zf F$a;jj0«***s
Aeronautics
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
