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 330
this may be done by mounting a second mirror on the endof the camera at such an angle that the field of view is reflectedinto the eye; but it will seldom happen that any very certainaim can be taken in this way. Vautier-Dufour and the astronomer Schaer of Geneva havedesigned a novel type of… … Fig. 192. -Vautier-Dufour apparatus, packed in itscase. passing through the lens, is reflected by a mirror at the back ofthe upper half to another mirror at the front of the lower half;it then passes from the lower mirror to the plate at the back ofthe lower half ofthe apparatus. Thelength of…
Aeronautics
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