LUMINOUS PAINT. 271 



natural slime upon it, then looking at it in the dark. A 

 sole or almost any other fish will answer the purpose, but I 

 name the smelt from having found it the most reliable in 

 the course of my own experiments. It emits a dull, ghostly 

 light, with very little penetrating power, which shows the 

 shape of the fish, but casts no perceptible light on objects 

 around. 



Thus the phosphorescent parish-clock face, with non- 

 phosphorescent figures and hands, would look like a pale 

 ghost of the moon with dark figures round it, and dark 

 hands stretching across, by which the time of the night 

 might possibly be discovered there or thereabouts. This 

 invention has already appeared in a great many para- 

 graphs, but, hitherto, upon very few clock-faces. 



Eecently it has assumed a more ambitious form 

 patented, of course. The patentees claim an improved 

 phosphorescent powder, which is capable of being worked 

 up with the medium of paints and varnishes, and thus 

 applied, not merely to clock-faces, but to the whole of the 

 walls and ceilings of any apartment. In this case the faint- 

 ness of the light will be in some degree compensated by the 

 extent of phosphorescent surface, and it is just possible 

 that the sum total of the light emitted from walls and 

 ceiling may be nearly equal to that of one mould candle. 

 If so, it will have somewlue as a means of lighting powder 

 magazines and places for storage of inflammable compounds. 

 It is stated that one of the London Dock companies is 

 about to use it for its spirit vaults ; also that the Admiralty 

 has already tried the paint at Whitehall, and has ordered 

 two compartments of the Cornus to be painted with it, in 

 order to test its capability of lighting the dark regions of 

 ironclad ships. 



This application can, however, only be limited to those 

 parts which receive a fair amount of light during the day, 

 for unless the composition first receives light, it is not able 

 afterwards to emit it, and this emission or phosphorescence 

 only continues a few hours after the daylight has passed 

 away ; five or six hours is the time stated. 



A theatrical manager is said to be negotiating for the ex- 

 clusive right to employ this weird illumination for scenic 



