Reflecting telescopes: 1. Dominion Astrophysical Observatory, Victoria, B.C. Reflecting telescope with 72-in. mirror.2. Equatorial telescope at Columbia university. (The rising floor is about one-third of the way from the top.) 3. U.S. Naval Observatory, Washington. 26-in. Equatorial with which the satellites of Mars were discovered in 1874 & 6. The Lick Observatory: 36-in. refractor with spectrograph attached and (6) the Crossley reflector, showing moving observing platform5. A l/10th scale model of the 200-in. telescope in process of assembly for use of the California Institute of Technology on Mt. Palomar, California.7. This is a cutaway model showing the 200-in. telescope in the dome. Dated 20th Century.