. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. it to the screen ; and the same arrange-ment is very convenient for working out a diagram before aclass. This is generally effected by some form of the verticalattachment devised by Professor Morton, and shown in fig. 89,a similar arrangement by Stohrer of Leipzig being shown infig. 116, on page 227. The lantern condensejs are arrangedso as to throw a parallel beam, which by a large reflector at anangle of 45° is deflected vertically, where it passes through a APPARA TUS FOR SCIENTIFIC DEMON
. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. it to the screen ; and the same arrange-ment is very convenient for working out a diagram before aclass. This is generally effected by some form of the verticalattachment devised by Professor Morton, and shown in fig. 89,a similar arrangement by Stohrer of Leipzig being shown infig. 116, on page 227. The lantern condensejs are arrangedso as to throw a parallel beam, which by a large reflector at anangle of 45° is deflected vertically, where it passes through a APPARA TUS FOR SCIENTIFIC DEMONS TRA HON 167 third plano-convex lens, which converges the light, and overwhose face is the field of the instrument. A pillar at the sidesupports the focussing power, a ring allowing various powersto be used: and the same ring-fitting carries a second silveredreflector, turning on an axis so as to throw the image at anydesired height on the screen. If a sheet of fine ground orsmoked glass be simply laid over the face of the large lens, adiagram can readily be worked out, and is often better under-.
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Keywords: ., bookauthorwrightle, bookcentury1900, bookdecade1900, bookyear1906
