History, theory, and practice of the electric telegraph (1866)
Prescott, George B.(George Bartlett),1830-1894 · Boston, Ticknor and Fields · leaf 139
the supply pipe, through one of the side passages,into the second chamber, at the same time that air on the otherside of the piston, in the second chamber, escapes back into thegrooves 1 and 2 of the valve, through the other side passage, an-thence into the atmosphere. This causes the piston to… … Fig. 64. rest on the teeth of an escapement-wheel of the printing ma-chine, A. This part of the apparatus is arranged on a circulariron plate, twelve or fourteen inches in diameter, supported bystandards on the mahogany frame, H, Fig. 61. The escapement-wheel revolves on a vertical shaft, which…
Telegraph
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