. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. Fig. 135.—Mounting for Two Forka dicularly. the block k taking one out of the line of the will be seen that with this arrangement both forks can bereadily bowed by assistants, and will be firmly held. A ver/ simple apparatus is shown in fig. 136, as made byMiller, of Innsbruck, from a design by Prof. Pfaundler. Twoflat steel springs, f f, are mounted in a manner that needs nofurther explanation than the diagram, one being adjustable inposition, aid having a sliding weight. Both are
. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. Fig. 135.—Mounting for Two Forka dicularly. the block k taking one out of the line of the will be seen that with this arrangement both forks can bereadily bowed by assistants, and will be firmly held. A ver/ simple apparatus is shown in fig. 136, as made byMiller, of Innsbruck, from a design by Prof. Pfaundler. Twoflat steel springs, f f, are mounted in a manner that needs nofurther explanation than the diagram, one being adjustable inposition, aid having a sliding weight. Both are furnished withmirrors. The springs maybe bowed, or are readily set in motion 82 26o OPTICAL PROJECTION. Fig. 136 by twitching with the finger. As far as regards the projection,this is cheap and efficient, but is not audible ; it has the advantage, however, ofproducing the figure bymotions of the samekind as a couple of projecting thefigure only, the ap-paratus shown in has been devisedby Pfaundler, who de-scribed it in the Pro-ceedings of the ViennaAcademy (of Sciences)and figures it in his Lehrbuch der vibration of twosprings s, s, set rect-angularly to each other, one variable by a weight, l, is givento two discs, d d, with slots which also cross at right angles.^^r, The spot of light ZyfllJiKilP where they cross, evidently movesin a path com-pounded of thetwo discs arearranged in frontof the condensers,the spot beingfocussed as anordinary dia-gram, and the springs twitched. Stohrer has constructed amore complicated apparatus for giving the same motions totwo discs by a wheel and gearing, methods of which will
Size: 1598px × 1563px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorwrightle, bookcentury1900, bookdecade1900, bookyear1906
