272 SCIENCE IN SHORT CHAPTERS. 



purposes. The sepulchre scene in " Robert le Diable," or 

 the incantation in "Der Freischutz," or "The Sorcerer," 

 might be made especially effective by its ghostly aid. The 

 name-plates of streets, and buoys at sea might be advan- 

 tageously coated with such a composition; and many other 

 uses suggest themselves. 



There are rival inventors, as a matter of course. The 

 French patentees claim the use of cuttle-fish bones, various 

 sea-shells, etc., mixed with pure lime, sulphur, and calcined 

 sea-salt, besides sulphides of calcium, barium, strontium, 

 uranium, magnesium, or aluminium. They also add phos- 

 phorus itself, though for what purpose is questionable, see- 

 ing that this substance is only luminous during the course 

 of its oxidation or slow combustion, and after this has ended 

 the resultant phosphoric acid is no more luminous than 

 linseed oil or turpentine. An admixture of phosphorus 

 might temporarily increase the luminosity of a sample, but 

 any conclusions based upon this would be quite delusive. 

 They also assert that electrical discharges passed through 

 the paint increase its luminosity. According to some en- 

 thusiasts, electricity is to do everything ; but these ladies 

 and gentlemen omit to calculate the cost of rousing and 

 feeding this omnipotent giant. In this case electrical ma- 

 chinery for stimulating the paint for anything outside of 

 lecture-table experiments or theatrical and other sensational 

 displays, would be a commercial absurdity. 



The Americans, of course, are re-inventing in this direc- 

 tion, but Mr. Edison has not yet appeared on the luminous- 

 paint scene. If he does we shall doubtless hear of some- 

 thing very brilliant, even though we never see it. In the 

 meantime we may safely hope that this application of an 

 old .scientific plaything to useful purposes may become of 

 considerable utility, as it evidently opens a wide field for 

 further investigation and progressive improvement, by the 

 application of the enlarged powers which modern science 

 places at the disposal of ingenious inventors. We hope, 

 for the sake of all concerned, that it will not fall into the 

 hands of professional prospectus manufacturers and joint- 

 stpck-company mongers, and that the story of its triumphs 

 will be told without any newspaper exaggerations. 



