SCIOPTICONMANUAL. 43 



roll it up while the dissolver passes over; the snow 

 shows plainer and plainer, till nothing but the falling 

 snow appears. Now place in H the same view in winter 

 and turn back the dissolver ; the storm subsides, and 

 the farm-house scene again appears in the morning 

 light, covered with the newly fallen snow of the win- 

 ter's night. 



To bring out statuary on a blue ground, a slide of 

 blue glass, and usually one of red glass also is used. 

 Change any scene, first into a red disk, then the red 

 into blue, and then let a piece of statuary slowly come 

 out into the blue ground, while the blue becomes darker 

 and darker, till it ends in a blackness which seems to 

 add vigor to the representation. 



A beautiful effect is produced by a wheel chromatrope, 

 used continuously in one of the lanterns, while a series 

 is shown in the other, turning it inward and outward 

 alternately, as the dissolving proceeds. It thus seems 

 to suck up the vanishing scene as in a maelstrom, and 

 to bring out its successor with scintillations of colored 

 lights. 



A pleasing effect is produced by showing a series of 

 views in one lantern, and a veranda, or some appropriate 

 design with opaque centre, with the other. If in adopt- 

 ing this suggestion, the veranda be focused for the edges 

 of the field, and the view focused for the centre, a flat 

 field is obtained over the entire disk. In this case, and 

 in all cases when light from both lanterns is to appear, 

 the dissolver is slipped up an inch higher, and kept in 

 position as in Fig. 16. 



The slow or dissolving process may become monoto- 

 nous, and it is not always appropriate. We hardly like 

 to see "Pilgrim" in his "Progress" fading away, while 

 his double by his side is slowly growing in strength and 



