. The art of projecting. A manual of experimentation in physics, chemistry, and natural history, with the porte lumière and magic lantern. nch funnel, such as is used in chemicallaboratories, a piece of tissue-paper or thin rubber. Apiece of rubber tubing, two or three inches long, maybe drawn over the stem of the funnel, and the otherend drawn over the mouth of a common jewelers blow-pipe. A sheet of pasteboard may now be rolled solarge that the broad end of the funnel, which has thetissue-paper pasted to it, may fit snugly in it. Thewhole fixture may now be supported in any way, bymeans of r
. The art of projecting. A manual of experimentation in physics, chemistry, and natural history, with the porte lumière and magic lantern. nch funnel, such as is used in chemicallaboratories, a piece of tissue-paper or thin rubber. Apiece of rubber tubing, two or three inches long, maybe drawn over the stem of the funnel, and the otherend drawn over the mouth of a common jewelers blow-pipe. A sheet of pasteboard may now be rolled solarge that the broad end of the funnel, which has thetissue-paper pasted to it, may fit snugly in it. Thewhole fixture may now be supported in any way, bymeans of retort-stands. A gas-flame from a smallround orifice, or a common candle may be used for theflame; the end of the blow-pipe is to be inserted in theblaze, with the opening upward. If now, either a com-mon mirror be used to give angular motion to the re-flected beam, or the concave mirror to reflect the flameupon the screen, while a sound is made in the large ACOUSTICS. 65 tube, it will disturb the flame so much as to give a dis-tinctly serrate image either upon the screen or in theplain mirror. The annexed figure will give an idea of. Fig. 41. the arrangement mentioned: a is the tube for produc-ing sounds, in b is the funnel with tissue-paper over itsmouth, c rubber connection to the blow-pipe //, whichopens upward into the flame from the candle e. THE ORGAN-PIPE. The vibrations of the air reed of a sounding organ-pipe may be shown, by having a small pipe made ofiron gas-pipe and blown by illuminating gas, which maybe lighted ; and when the pipe is sounding the reed willbe seen to swing backward and forward in front of theembonchure. That it really vibrates may be seen by re-flecting the light from a mirror upon a screen, and tilt-ing the mirror, as is done in showing the manometricflames. machs experiment. The movement of the air within a sounding organ-pipe has been studied optically by Mach, a Germanphysicist. His method was to stretch a membraneacross the node of a pipe wit
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherbosto, bookyear1877
