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100 MODBEN MAQIO LANTEBN8. tions it can be replaced by a slightly modified form of compound microscope, which is attached in front of the condenser of the usual lantern. In Fig. 72 a simple form of compound microscope is shown, which can in a few moments be removed from the stand on which it has served as a table microscope and placed on the lantern nozzle, as shown in the top right-hand figure. The objectives of various powers can be slipped into the racked mount, those most commonly supplied being 1- and 2-inch powers. An additional lens as a supplementary condenser is some- times fitted between the chief condensers and the object, and when properly adjusted this much improves the illumination. The real difficulty in microscopic projection has always been the proper illumination of the object. Lantern micro- scopes cannot be expected to yield as bright images on the screen as ordinary lanterns showing slides vrith but a fraction of the magnification. In consequence, the operator's attention should be given to the proper adjustment of the light and con- densers. The light concentrated on the small surface of the slide will soon make it very hot unless prevented by means of an alum trough (see p. 84); this in micro-projection should never be omitted, or it will lead to the ruin of the slides. The sUdes in the simpler forms of lantern microscope are fitted in wooden frames like ordinary lantern slides, only these frames are smaller. Frames can be obtained one end of which takes out to receive the usual size of microscope slide, for use in the lantern. These are a convenience, but it is decidedly preferable to have a microscope attachment with the usual form of plain sliding stage, so that the slides can be used direct without any further mounting. This is the case with the instruments shown in Figs. 72 and 73. Too great a degree of magnification should not be attempted until the management of the lantern with low powers has been thoroughly mastered. A 1-inch objective will' be found the most powerful which can be used in the ordinary way with satisfactory results, both as regards illumination and other quaUties. On changing the objective the position of the jet should be altered until the best fighting is secured, as it will be found that lenses of different powers require the