Descriptive 

 Electricity. 



Phospho- 

 rescent ef- 

 fect* of 

 electricity. 



ELECTRICITY. 



TABLE, shewing the Results obtained by exploding compound Cans. 

 Names of the Compound Gases. Heiulti. 



Muriatic acid Hydrogen. * 



Fluoric acid Hydrogen. * 



Nitrous gas Nitric acid and nitrogen. 



Carbonic acid Carbonic oxide and oxygen. 



Sulphuretted hydrogen Sulphur and hydrogen. 



Phosphuretted hydrogen Phosphorus and hydrogen. 



Ammonia Hydrogen and nitrogen. 



Olefiant gas Charcoal and hydrogen. 



Carburetted hydrogen Charcoal and hydrogen. 



503 



Decrfptive 

 Electricity. 



The phosphorescent effects of electricity have been 

 successively investigated by Mr Canton, Mr Lane, Mr 

 Wilson, Mr Morgan, Mr W. Skrimshire, jun. and Mr 

 Singer. Mr Skrimshire in particular hasexamined a great 

 number of bodies, and has published the results which he 

 obtained in the 15th, 16th, and 19th volumes of Nichol- 

 son's Journal. He placed the substance to be examined 

 on a brass plate, fixed horizontally on the knob of the 

 prime conductor, by a thick piece of wire, and he en- 



deavoured to take the spark from it by means of the ball Phospho- 

 of the discharger. It wasafterwards placed upon a wood- J cscen * * 

 en stand, and the shock of a Leyden phial first passed 

 over it, about a quarter of an inch above its surface, by 

 resting the points of the discharging rods at the dis- 

 tance of an inch or more from each other upon the stone 

 to be tried. In all the experiments it is necessary to 

 close the eyes till the explosion be heard. In this way 

 Mr Skrimshire obtained the following results : 



TABLE, containing Mr Skrimshire's Experiments on the Phosphorescent Effects of Electricity upon different 



Bodies. 



Cakareotit Gemtt. 



Eiperi- Calcareous spar, Rendered very luminous by the shock. Experi- 



ments of ... f Very luminous when the shock passed above it. When passed along its ments of 



Mr skrim- < | surface, a zigzag track of light continued several minutes. M 5 sk n- 



K tt st ne ^ >art ^ *^ e stone snatteret l> and its luminous grains dispersed in all direc- "" 



tions. 



Selenite, Shines for a few seconds with a vivid greenish light. 



Fresh nitrate of lime, Gave small sparks, which were red flame-coloured upon its surface. 



Muriate of lime, More phosphorescent than the nitrate of lime. 



Dark purple fluor spar f Gave no sparks, but the electric fluid passed in a purple stream with 



J whizzing noise. 



Yellowish fluor spar, Gave very good sparks, while dark purple fluor spar gave none. 



The most luminous of any substance by the electric explosion. 



Phosphate of lime, A minute red spark. It is inflammable by a very small shock. 



Calcined oyster shells, Are rendered beautifully luminous, and give the prismatic colours. 



Ditto calcined with sulphur, Give a durable and bright light, according to Mr Singer. 



Barytic Genus. 



Carbonate of Barytes, No spark, but very luminous when the shock was passed above it. 



Sulphate of Barytes fGood sparks, but slightly luminous. According to Singer, it gives tt 



^ bright green light, more bright than that of the carbonate. 

 Sulphuret of Baryhw, Was slightly luminous by the electric explosion. 



Muriatic Genus. 



Magnesia, pure and carbonated, . . . Were both transiently luminous by the electric explosion. 



Sulphate of magnesia, Very luminous through its whole substance. 



Sulphuret of magnesia, Not more luminous than the carbonate. 



Chlorite, Sparks branching off in minute party-coloured points. 



Steatites, talc, and fibrous amianthus, Gave sparks, and were slightly luminous by the explosion. 



Axbestus, Ramifications on its surface more variegated than in chlorite. 



Mica Affords sparks, but is not luminous by the explosion. 



Micaceous schistus, Sparks ramified as in chlorite, scarcely phosphorescent. 



Argillaceous Genus. 



Alum, Spark purple, rather ramified, luminous through its whole surface. 



Pipe clay, Sparks, and luminous, but not luminous when made into pipes. 



Theee roulu are given on the authority of Dr Henry and Mr Dalton. 



