Appleton's dictionary of machines, mechanics, engine-work, and engineering (1869)
New York, Appleton · leaf 622
R- … There is another precaution of more importance, which consists of having always at hand in thelight-room a spare lamp, trimmed and adjusted to the height for the focus, which may befor the other in case of accident It ought to be noticed, however, that it takes about twenty minutesfrom the time…
Mechanical engineering
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
