A Treatise on Telephony Volume 1

A Treatise on Telephony Volume 1

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 edition. Excerpt: ...filings as before. (a) Make a sketch showing the direc tion of the lines of force of the field re sulting from the two magnets, as shown F1"-9" by the forms assumed by the iron filings.-(b) Reverse the bar magnet, i. e., place its north pole where its south pole is in Fig. 938 and repeat the experiment, making a sketch as in (a). These formations of iron filings in magnetic fields may be preserved as follows: Take a piece of window-glass of suitable size and heat it over a stove or flame until a small piece of paraflin placed upon it melts. Let the melted paraflin spread evenly in a thin coat over the glass plate, and then let the plate cool in a horizontal position, so that the paraflin will harden in a layer of even thickness. Vhen the.parafl'in is hard, place the plate over the magnets, suitably arranged, and on the paraflin side of the glass sprinkle the iron filings. Tap the plate lightly to settle the filings in their places, then lift the plate 2'cents'rl1'm/l_1/ off the magnets until beyond their influence. Again hold the glass plate over the stove or flame until the paraffin again melts, taking pains to hold the plate /zorz'/zonlally. Theparaffin layer being thin, it will not then run, and the filings will retain their regular positions. VVhen the paraffin is melted, carefully remove the plate to a cool spot, and again let the par 'affin harden. If these operations have been carefully gone through with, the filings will be fastened in place by the paraffin and their graceful and instructive forms preserved, making a permanent r, ecord. These glass plates may be used as negatives and blue-prints, or photographs may be printed from them. Experiment 8.--(Art. 2368.) In the two sketches above, point out (bshow more

Product details

  • Paperback | 180 pages
  • 189 x 246 x 10mm | 331g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236826965
  • 9781236826961