THE LANTERN MICROSCOPE. 229 



Mr. Browning has prepared a nose-piece for lanterns, 

 which he calls the " Lantern Microscope," by the use of 

 which the ordinary 3 X i microscopic slides may be 

 displayed upon the screen. Its form may be seen in 

 Fig. 200. 



FIG. 200. 



It is composed of the following parts, conveniently 

 mounted in brass, with rack adjustments and other requi- 

 sites, and so arranged that it can immediately replace the 

 ordinary front combination of first-class lanterns: (i) 

 Lenses acting as an achromatic condenser, receiving the 

 light that passes through the large lenses of the lantern 

 and reducing the light-pencil to the proper size. (2) An 

 object-holder for 3 x I inch slides. Then follows the 

 magnifying apparatus, as in a table microscope namely, 

 an achromatic objective, made specially for this instrument, 

 and a Kelner eye-piece, giving considerable amplification 

 with a very wide field. The light-pencil must be adjusted 

 by means of the rackwork attached to the second con- 

 denser, and an image of the object to be displayed must be 

 received on a well-strained paper screen, and carefully 

 focussed by turning the milled head furthest from the 

 object. The objects best suited for display are transparent 

 injections, which should be thin and not too darkly stained ; 

 entire insects, mouth organs, tracheal tubes, &c., of the 

 larger kinds, sections of wood, tissues and organs of plants, 

 preparations of zoophytes, sections of coal and other 

 minerals. To prevent disappointment, it should be remem- 

 bered that transparent objects, such as diatoms and the 



