. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. the outside of the chest upon thescreen, or simultaneously with a pulse-tracing. All that isreally necessary is to adjust the clock-work movement andthe traverse of the tracing point, to the size of the fieldcovered by the condensers of the lantern. As regards theprojection itself, it is only needful to secure an evenly illu-minated disc, in the manner described on p. 115, for the focalplane which is to be occupied by the blackened glass. This 236 OPTICAL PROJECTION is accomplished by focuss
. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. the outside of the chest upon thescreen, or simultaneously with a pulse-tracing. All that isreally necessary is to adjust the clock-work movement andthe traverse of the tracing point, to the size of the fieldcovered by the condensers of the lantern. As regards theprojection itself, it is only needful to secure an evenly illu-minated disc, in the manner described on p. 115, for the focalplane which is to be occupied by the blackened glass. This 236 OPTICAL PROJECTION is accomplished by focussing a plate of glass with a few linesmarked upon it, and adjusting the light for this; and thenmaking every smoked plate occupy the same position as nearlyas possible, throughout the series of demonstrations. The movements of the heart have been projected by othermethods. The apparatus shown in fig. 122 is extremely heart freshly taken from the living frog or other animal isembedded in sufficient warmed wax to form a steady base,and laid on the plate a. Above it extends a light lever, fd,. Fiu. 123.—Czermaks Cardioscop* bearing an index-disc, /, at the end, or it may be a style; thishas a very sensitive joint at d i, which can be adjusted length-ways over the heart by the screw g, and this and the otherscrew g also serve to adjust lever and stand on the pillar some experiments requiring great delicacy, it may beadvisable to carefully balance the arm fc, or the somewhatsimilar arms in fig. 121, so that their weight may not inter-fere with the motion. Between the heart and the lever at cis adjusted a small pillar b of elder pith, with a small point ateach end, which communicates the motion, the lower point PHYSIOLOGICAL DEMONSTRATION 237 being sunk in the heart. The motions of the heart, which canbe kept beating rhythmically by well-known methods, arethus readily projected, as shown by the disc on a point at/. The same apparatus projects the contractile movements
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Keywords: ., bookauthorwrightle, bookcentury1900, bookdecade1900, bookyear1906
