Bromide paper : instructions for contact printing and enlarging (1896)
Just, E. A · Bradford : P. Lund, Humphries · leaf 46
ave, besides, a small signal bell, which sounds after a certain number of oscillations, this number being regulated by a lever. The price of these instruments ranges between iis. and 17s. Thesignal bell attachment facilitates the work, as no doubt occurs regarding the number of oscillations that… … with signal bells. A piece of clockwork is connecfled in the elecftric circuit of a galvanic battery in such a way that the current passes through the hand of the clock and through the metallic dial, which is insulated from the hand. Over the dial is placed a piece of paper cut out in parts, as…
Photography
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
