Collins, A. Frederick (Archie Frederick), 1869- · New York, London, D. Appleton and company · leaf 61
nchthick and bore a %-inch hole through it near one end. To the other end of *thisBACKl>F.i1|RROR stick fasten a mir-H/N|p ror about 4 inches square. This mirrorshould be perfectlysmooth—a plateglass mirror is thebest — and have a hole Yie *nck *n <fr* ameter drilled through the center of the… … Fig. 41.—Back View op Heliograph. THE SUN, BRIGHTEST OF ALL STARS 41 Make a wood frame so that the mirror can be fastened in itand screw the frame to a stick of wood. Get a bolt 5 incheslong and % inch in diameter and have a thumb screw fittedto it. Set the end of the stick which has the mirror…
Astronomy · Stars
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