. The art of projecting. A manual of experimentation in physics, chemistry, and natural history, with the porte lumière and magic lantern. op of the tuning-fork is above the glass. Seize thetwo prongs of the fork with the thumb and forefinger,and pinching them close together, suddenly let it wire finger will trace a sinuous line upon the pre-pared surface, caused by the vibration of the forkduring its descent. The undulations will be seen toincrease in length as they approach the bottom; but aseach one was made in the same time with every otherone, it is obvious that the velocity incr
. The art of projecting. A manual of experimentation in physics, chemistry, and natural history, with the porte lumière and magic lantern. op of the tuning-fork is above the glass. Seize thetwo prongs of the fork with the thumb and forefinger,and pinching them close together, suddenly let it wire finger will trace a sinuous line upon the pre-pared surface, caused by the vibration of the forkduring its descent. The undulations will be seen toincrease in length as they approach the bottom; but aseach one was made in the same time with every otherone, it is obvious that the velocity increased as it wasfalling. In order to show this, it is merely necessaryto put the apparatus near the condensing lens, andproject the face of the glass. The line traced by thefork will be seen upon the screen. It will now be wellto measure the lengths of the undulations, which canbe very well done by having a scale in millimetersetched, or otherwise fixed upon another glass, whichcan be put just in front of the first, when the number ofdivisions of the scale to each undulation can be counted,and the result stated in mathematical PHYSICAL EXPERIMENTS. 57 plateaus experiment. With the vertical attachment and a tank, made five orsix inches deep and with a plane glass bottom, thisbeautiful experiment, which so well illustrates cohesionand centrifugal force, may be projected. Fig. 36 shows the proper wire, w^ is made torevolve vertically i nthe tank, by means ofa little pulley drivenby a cord about a larg-er one, at /, the wholeso made as to rest uponthe edge of the , 36. and supported by ears, as shown. The wire, w^ should have a thin disk of tinfastened to it at s, for a surface of adhesion. Now thesolution may be one of alcohol and water, so graduatedthat its specific gravity shall just equal that of the oilused, which can only be done by trial in a test-tube ;or it may be a solution of zinc sulphate, and the spheremay be made of bisulphide of carbon, w
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherbosto, bookyear1877
