We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
CHAPTER II.
THE MAGIC LANTERN WITH AN ALTERNATING CURRENT ARC LAMP AND ITS USE
§ 100. Apparatus and Material for Chapter II:
Suitable room with screen (Ch. XII) ; Magic lantern with lantern table (§ 102); Arc lamp for alternating current with 'suitable carbons (§ 108); Alternating current supply ; Rheostat, choke-coil or other balancing device (§ 105-106); Ammeter for alternating current (§ in); Incandescent lamp, flash-light, gloves with asbestos patches, testing lamp, fuses, extra condenser lenses, screw driver, pliers, opera-glasses, lantern slides as in Ch. I (§ i).
§ 101. For the historical development of the alternating current arc lamp see the Appendix ; and for the character and advantages and disadvantages of alternating current see § 652-653, and modern works on the subject.
The same books of reference given in § 2, Ch. I, are available for this chapter.
COMPARISON OF ALTERNATING AND DIRECT ELECTRIC CURRENTS AND LANTERNS
§ 102. A magic lantern for alternating current may be precisely like one for direct current, the only essential difference being that the arc lamp must be of the hand-feed type and the mechanism for feeding the carbons gives equal movement to the upper and to the lower one, both carbons being of the same size.
One would never use an alternating current with the magic lantern if direct current were available. It frequently happens, however, that the lighting system of a place is of the alternating current type, and no direct current is available. In such a case one must make the best of it, or use a motor-generator set or a rectifier (see § 682-683).
The objections to an alternating current for the arc lamp in projection are: (i) The lamp is noisy; (2) It requires about two and one-half times as much current for the same effective light.
68