Chapter II: ASTRONOMY.--Astronomical Telescopes; their object glasses

and reflectors.--By G.D. HISCOX.--The dialyte telescope;
practical details of the mechanical operations of
construction, such as lens grinding and shaping; washing
flour of emery, tests for correction.--23 illustrations 9296

Fleurials' Gyroscope Collimator.--An ingenious application of
the gyroscope to fixing the horizon line in sextant
observations; an instrument crowned by the French
Academy.--2 illustrations 9291