MAGIC LANTERNS. 211 



ing towards the screen to diminish the image, it will appear 

 to them as if it was receding. 



The only difficulty in making this exhibition, is in sliding 

 the tube in or out properly to keep the image perfect : no 

 rule can be given that would be of any service, but the 

 operator will soon perceive that when the image is got to a 

 moderate size, the tube requires to be slid in very little to in- 

 crease it ; but when the image is about four or five inches 

 diameter, to reduce it to one half that size, the tube will re- 

 quire to be drawn out more rapidly : practice alone will 

 enable him gradually to reduce or enlarge the image, and at 

 the same time to keep it distinct. 



To give Motion to the Images. A variety of movable 

 sliders are made for this purpose, many of which produce 

 very curious appearances, but with the usual sliders the 

 images may be made to move in a circular, elliptical, or other 

 direction, by moving the lantern in the corresponding way, 

 which will of course produce the like motion in the images. 

 A curious effect is also produced by drawing out the tube 

 and slipping it in suddenly to the focus ; this is easily done 

 by holding the tube tight at the proper place. A shivering 

 motion may be given to the images by giving the lantern a 

 sudden shake. By standing at the bottom of a pair of stairs, 

 a figure may be made to appear going up, by giving the 

 lantern a slight angular motion ; the figure of the skeleton 

 is a very good one for this purpose : in the same way this 

 figure may be made to lie on the floor and rise up to a sit- 

 ting or standing posture. By combining the motion of the 

 lantern with movable sliders, a great variety of curious 

 effects may be produced, particularly on the transparent 

 screen ; many of these are often exhibited in public, and 

 from what has been said, those who take pleasure in this 

 machine, will soon be able to produce most of them. 



Description of Carpenter's Improved Lucernal Microscope. 

 This microscope is used to exhibit transparent objects on 

 a scieen or white wall, in the manner of the solar micro- 

 scope ; though from the difference in the intensity of the 

 solar light and that from a lamp, the effects are very inte- 

 rior. The lucernal microscope has, however, some advan- 

 tage over the solar ; it can be used by night, and in the long 

 evenings, when amusements are most necessary ; it is more 



