42 SCIOPTICON MANUAL. 



moving of the dissolver will very mysteriously dissolve 

 one view into another. 



This effect is commonly produced with slides not spe- 

 cially arranged for the purpose, but it is desirable that 

 they should be of similar size and shape, and that they 

 should be put in evenly, so as to cover the same spaco 

 on the screen. 



Many slides are, however, selected and executed with 

 special reference to their producing charming effects in 

 dissolving. 



They are mostly arranged in pairs, as some view in 

 summer and the same in winter, by day and by night, 

 interior and exterior, in sunshine and in storm, or hu- 

 manity in opposite moods. Sometimes the series are 

 more extended, as the Seasons, the Yoyage of Life, &c., 

 and sometimes they are in connection with chroma- 

 tropes to represent volcanic action, conflagrations, fire- 

 works, turning mills, &c. Suppose, for example, Saint 

 Peter's, at Rome, is thrown upon the screen from .72, and 

 a night view of the same is placed in Jj; then as the 

 dissolver is changed, Saint Peter's with its surroundings 

 continues on the screen, but an appearance of night 

 comes over it; the windows glitter with a thousand 

 lights, and the moon makes its appearance in the heav- 

 ens. Now, suppose a chromatrope, suited to the pur- 

 pose, is placed in .K, then as the change proceeds fire- 

 works will rise from the darkness, and illumine the sky. 



The snow effect is produced by a strip, usually of 

 silk, with pin-holes all over its surface, mounted on rolU 

 ers within a slide, so that when the silk is rolling up, 

 snowflakes appear on the screen to be falling. Let, for 

 example, a farm-house scene be projected from R upon 

 the screen, amid all the glory of summer vegetation ; 

 place the snow slide in L, and let an assistant slowly 



