112 ANNUAL OF SCIENTIFIC DISCOVERY. 



solution of sulphate of zinc, as well as of concentrated sulphuric acid, 

 is increased by a moderate addition of water, but again reduced by 

 greater dilution. Liebig's Annual Report. 



The researches of Professor Horsford, on the conducting power of 

 liquids, made contemporaneously with those of Becquerel, and publish- 

 ed some years since, have furnished many important facts on this 

 interesting subject. Editors. 



CONDUCTING POWER OF FLAME. 



IT has been long known that flame possesses a property subversive 

 of electricity, but with respect to the cause of this behaviour, the 

 labors of distinguished investigators, for upwards of one hundred 

 years, have only established thus much, that flame possesses a very 

 strong conducting power for electricity, which can neither be explain- 

 ed merely by the rise of temperature of the air, nor by any conduct- 

 ing property of the aqueous vapor, contained in the hot air of the 

 flame, nor by a current of air, or a removal of electricity by the vola- 

 tile particles that rise from the flame ; for not one of these influences, 

 by itself, evinces the conducting power in so high a degree as flame. 

 However, Volta made use of the flame of a lamp to draw electricity 

 from the air and collect it in his condenser. A few years since, 

 Riess observed that the action of flame extends over much greater 

 distances than docs the upward current of hot air, or than this could 

 make the air conductive ; and that this current does not move at all. 

 From this he concluded that the flame acts not only by direct com- 

 munication, but also by induction (influence), and hence he endeavour- 

 ed to reduce the effect of flame to that of points. He started from 

 the consideration, that the current of hot gas ascending from the 

 flame, and conducting the electricity, was repeatedly cut into and di- 

 vided by the cold air, (which does not conduct electricity) streaming 

 upon and penetrating it, so that there are formed points and threads, 

 as it were, of the conducting gas, which become more and more at- 

 tenuated, and are gradually dispersed through the air, under the influ- 

 ence of the colder surrounding medium. These serrations and points 

 now exert their powerful influence in inducing electricity in all direc- 

 tions, and to considerable distances, producing by these means the 

 effects of good conductors. The action of points is also exhibited by 

 substances that do not burn with flame, but merely smoulder, as 

 tinder, slow-match, &c. Riess, however, proves that in this case, 

 when they cannot be caused by the ascent of incandescent gases, 

 they originate in the combustion of the surface of the body itself. 

 These views involved Riess in a long scientific dispute, in which he 

 has increased the probability of his explanation. Liebig's Annual 

 Report. 



USE OF GUTTA-PERCHA IN ELECTRICAL INSULATION. 



DR. FARADAY, in a letter to Mr. R. Phillips, one of the editors of 

 the Philosophical Magazine, states that he has lately found gutta- 



