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SCIOPTICON MANUAL. 93 NATURAL OBJECTS, as leaves, plants, fibres, texturo of cloth, thin sections of wood, bone, &c., appear in dis- tinct outline upon a white ground. Live animals in the tank, as insects, larvse of gnats, shrimps, worms, lizards, &c., appear as huge monsters upon the screen, and excite a lively interest by their eccentric movements. VERTICAL LANTERN. —Some very interesting experi- ments require the slides to lie in a horizontal position. This is commonly effected by reflecting the light up through the glass plate and the objective lens, and then by another mirror reflecting the image horizontally to the screen. A lantern appendage of this sort in now in the trade, at $20. But this is equivalent to placing the slide at least four inches from the face of the condenser, which, at best, puts it at great disadvantage, and then there is the loss of light by two reflections. The oil light cannot well bear these drawbacks, the lime light is better; but with the lime light the Sciop- ticon may be placed on end, as shown at Fig. 30. When attached to its carrying box, in the ordinary way, it may be held in this position over the edge of a table, so as to be con- veniently operated. The front flame-chamber glass will protect the condenser from its greater liability to become heated. Fig ' 3O ' A glass disk, clean cut, and slightly larger than the condenser, answers for the slide plate; and if a rubber band be stretched about its periphery, like the tire of a wagon wheel, it will become a tank for fluids. With this arrangement, a mirror at an angle of 45° above the objective will throw the effect upon the screen without appreciable loss of light.