160 SCIENTIFIC RECREATIONS. 



For the winter evenings one may easily procure an apparatus for dis- 

 solving views by the oxy-hydrogen light. One, as shown in the illustration 

 herewith (fig. 1 69), will answer every purpose, and by this double arrangement 

 phantasmagoria may be produced, or a fairy tale may be illustrated. The 

 effect of gradually-approaching night may be given to the picture by means 

 of a special glass in the lower lanthorn. The apparatus is exhibited by 

 means of a Drummond light, and is very simple, although a certain supply 

 of gas is necessary for the performance. But this can be easily procured 

 by an indiarubber tube, or in a bag supplied for the purpose. Almost any 

 objects can be used, photographs, etc., etc., and many very comical arrange- 

 ments can be made. 



We have lately been reading a curious method of obtaining light from 

 oyster-shells in a Trans-Atlantic magazine. We give an extract wherewith 

 to close this chapter. The compound is " luminous paint." 



" It has been known that certain compounds of lime and sulphur had 

 the property of absorbing light, and giving it out again when placed in the 

 dark. A simple way to do this is to expose clean oyster-shells to a red 

 heat for half an hour. When cold, the best pieces are picked out and packed 

 with alternate layers of sulphur in a crucible, and exposed to a red heat for 

 an hour. When cold, the mass is broken up, and the whitest pieces are 

 placed in a clean glass bottle. On exposing the bottle to bright sunshine 

 during the day, it is found that at night its contents will give out a pale 

 light in the dark. Such a bottle filled more than a hundred years ago still 

 gives out light when exposed to the sun, proving the persistency of the 

 property of reproducing light. Very many experiments have been more 

 recently made in this direction, and the light-giving property greatly enhanced. 

 The chemicals, ground to a flour, may now be mixed with oils or water for 

 paints, may be powdered on hot glass, and glass covered with a film of 

 clear glass, or mixed with celluloid, papier-mache, or other plastic materials. 

 As a paint, it may be applied to a diver's dress, to cards, clock dials, sign- 

 boards, and other surfaces exposed to sunlight during the day ; the paint 

 gives out a pale violet light at night sufficient to enable the objects to be 

 readily seen in the dark. If the object covered with the prepared paint is not 

 exposed to the sun, or if the light fades in the dark, a short piece of 

 magnesium wire burned before it serves to restore the light-giving property." 



