Intelligence and Miscellaneous Articles. 549 



sandstone, and is of comparatively recent origin. It is light, burns 

 very rapidly, gives out great heat, produces 50 per cent, of ash, and 

 forms considerable quantities of clinker. 



2. Labuan, Borneo. — Several seams of coal crop out conspicuously 

 near the coast, the lowest being 1 1 feet 4 inches in thickness. It is 

 heavy, close-grained, fast-burning, and gives out considerable heat ; 

 it is of very recent date, — dammara resin and leaves of recent trees 

 being found associated with it. 



3. Diu, Saghalien. — Coal excellent, burns quickly, with little ash. 

 Presents a fracture similar to Welsh coal. 



4. Japan. — The author describes coal from several localities in 

 Japan as bright, clean, and resembling Sydney coal, but having a 

 tendency to form clinker. He concludes with a description of seme 

 coal from Ivanai, Niphon, which is very clean, highly bituminous, 

 burns with a flame in the flame of a candle, and would probably be 

 valuable as a gas-producing material. 



LXXII. Intelligence and Miscellaneous Articles. 



ELECTROSCOPIC NOTICES. BY PROFESSOR POGGENDORFF. 



"DYROXYLINE, or gun-paper, besides its great inflammability, is 

 ■■* well known to have the property of becoming strongly charged 

 with negative electricity by friction with most organic substances. A 

 strip of this paper drawn between the fingers is therefore in many 

 cases a very useful electroscope. With negatively electrified bodies this 

 electroscope can be used under all circumstances ; for it is repelled by 

 them ; but it can only be used with positively electrified bodies if 

 their electricity is so strong that it can act at considerable distances ; 

 for when near, the paper is attracted even by indifferent substances, 

 owing to inductive action. 



This objection led the author to consider whether it was not pos- 

 sible to find a substance which would furnish an equally trustworthy 

 electroscope for positive electricity. At first it was imagined that 

 the beard of the Chamois (Gemsbart), recommended by M. von 

 Kobell, might prove available ; and it may indeed be used, but, apart 

 from the circumstance that this substance is not at the disposal of 

 every physicist, it is both too fragile and too rigid. In the course 

 of his investigations the author found that there is more than one 

 substance with the desired properties and within every one's reach. 

 He was led to examine the deportment of metals when rubbed with 

 certain insulators, and he obtained certain points of view which in- 

 vested this well-worn subject with fresh interest. The insulators 

 investigated were the following : — Ebonite, gutta percha, caoutchouc, 

 patent caoutchouc (Patentgummi), waxed cloth, white wax, resin, 

 shellac, sealing-wax, sulphur, amber, copal, silk, gun-paper, collo- 

 dion, and gun-cotton. And the metals and conductors rubbed were 

 graphite, carbon (gas-carbon), platinum, gold, palladium, silver, 



