Scientific American Supplement, No. 648, June 2, 1888

Scientific American Supplement, No. 648, June 2, 1888

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Excerpt: ...theater, or in any way with the system outside the theater, the safety fuses would burst, and would so remove all danger from inside. The switch has now been turned, and by it the current from the Grosvenor Gallery has been brought within our reach. You see an arc light produced by it, and you see how intensely bright and brilliant that light is. I do not want you so much to see that light itself, but I want you to see its projection, or picture; and if Mr. Wickham will kindly direct it on that white paper, at the 10351 end of the room furthest from the table, you will see a picture of the carbons which are now emitting that intense and brilliant light. You will see that between what appears to you as the top carbon (but which is in reality the bottom carbon of the two) and the bottom one there is playing, apparently, a shower of minute fragments of something, but which are in reality innumerable minute flashes of lightning, there is a constant uninterrupted shower of electric shocks passing, that produce that intense brilliancy, and that very bright appearance. There is intense commotion, a terrible surging about of matter in a molten condition. Well, that arc that you see is produced by the currents from the Grosvenor Gallery. They are alternating currents of electricity, currents that are constantly and suddenly circulating backward and forward. The arc that we have at this other end of the room is a direct current one, and it is now projected on to another sheet of paper, where you see a different form of are altogether. This arc is produced by the direct current from a battery. You will see the form is quite different from that in the alternate current arc. You heard a peculiar hissing sound just now; that is a peculiar phenomenon in arc lamps that has attracted a good deal of attention from physicists, but nobody has yet arrived at a satisfactory conclusion as to the cause. The lamp sometimes sings and sometimes hisses, and while thus...show more

Product details

  • Paperback
  • 189 x 246 x 3mm | 100g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236728548
  • 9781236728548