Identifier: americanannualof1892newy (find matches)
Title: The American annual of photography
Year: 1892 (1890s)
Authors:
Subjects: Photography
Publisher: New York : Tennant and Ward
Contributing Library: Harold B. Lee Library
Digitizing Sponsor: Brigham Young University

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Text Appearing Before Image:
r what are all our curtains, head-screens, andreflectors in studios, but artificial, and sometimes inefficientmeans for producing the results which nature, out of doors,for generation after generation, has engrafted into our mindsas being beautiful. R. W. Harrison. AND PHOTOGRAPHIC TIMES ALMANAC. 163 THE PROJECTION OF DIAPOSITIVES BY THE ARC LAMP. Several times of late the attention of the writer has beencalled to the constantly increasing demand^ in camera andother clubs and societies for some means of using the lanternfor projections without the expense and trouble of the oxy-hy-drogen lamp, and he is therefore led to give his own experiencewith electricity. Some time during the year 1885 the writer assisted in wiringthe lecture room of a professor in a college near New York,who constantly required the use of a stereopticon in theillustration of lectures. As will be seen by the accompanying diagram all thearrangements were very simple, and can easily be duplicated byanv electrician.
Text Appearing After Image:
A lens, B slide, D lantern, C condenser, L arc lamp, double feed, S screw, R returnwire, M lead wire, X incandescent lamps as extra resistance, Y carbons. In the cut as above, L represents a focusing arc lamp, thecarbons being fed up and down by clock-work, so as to keepthe arc constantly in the center of condensing lens. Our lamp was so small, and had such light carbons, theybeing only one-quarter of an inch in diameter, that it wasnecessary for us, in some measure, to reduce the force of thecurrent supplied us from the street-mains at an intensity of105 volts, to prevent our lamp from being fused. This was accomplished by inserting in series in our lead wire 164 THE AMERICAN ANNUAL OF PHOTOGRAPHY, from four to six fifty-candle Edison incandescent lamps, thusgiving perfect control of current-supplied arc-lamp. Shouldthis number, six, be found too great, one or more could readilybe unscrewed from its socket, and a fusible plug of practicallyno resistance substituted. This reduction of

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