Collins, A. Frederick (Archie Frederick), 1869- · New York, London, D. Appleton and company · leaf 60
III (Mil ffifflffi .ittiti … T Fig. 39.—Continental Morse Code. 40 THE BOOK OF THE STARS long flash a dash and short and long flashes represent letters.This is the same code that is used for wireless telegraphy. How to Make a Simple Heliograph.—A heliograph ismerely a mirror mounted on a baseboard, but this is a big…
Astronomy · Stars
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