COMPARATIVE SPEED OF LIGHT AND ELECTRICITY.--The French physicist Fizeau calculated the velocity of light at 185,157 miles a second; Cornu, another Frenchman, calculated it at 185,420, and Michelson obtained 186,380 as the result of his calculation. Wheatstone, the English electrician, found that free electricity travelled 288,000 miles a second; Kirchoff concluded, from theoretical considerations, that an electrical current sent through a wire in which it meets no resistance has the velocity of 192,924 miles a second. The velocity of an electric current sent through iron wire is 62,100 miles a second; through copper wire, 111,780 miles. We think justice will be done by deciding that electricity is the faster.--_N. Y. Sun_. Yet practically speaking, electricity in wires is much slower. Prof. Gould found that telegraph wires at a moderate height, transmit signals at the rate of 12,000 miles a second; but if the wires are suspended high enough, the velocity may be raised to 16,000 or even 24,000 feet a second. Subterranean wires and submarine cables transmit slowly. Wheatstone's experiments were made fifty-four years ago, and have not since been confirmed. I would say light is the faster, for electric currents are always retarded by the medium. WONDERFUL PHOTOGRAPHY.--Dr. H. G. Piffard exhibited in New York to a society of amateur photographers a new method of taking instantaneous photographs by means of a brilliant light made by sprinkling ten or fifteen grains of magnesium powder on about six grains of gun-cotton. When this is flashed in a dark apartment it gives light enough to take a good photograph. It will do the same if flashed out of a pistol; so that a citizen may have his revolver with a small camera on the barrel and by flashing the gun-cotton out of his pistol he can make a photograph of any burglar or robber in the dark before he fires a bullet. WOODEN CLOTH.--An Austrian has patented a process for boiling wood and cleaving it into fibres that may be spun into threads which may be woven. THE PHYLLOXERA pest, which has wrought such havoc among vineyards throughout Europe, has invaded California also. France has lost many millions, and has offered a reward of 300,000 francs for the discovery of a remedy. A Turkish farmer is said to have discovered accidentally that the remedy is to plant Sorghum or sugar-cane between the vines, which draws the phylloxera from the grapevines. It is said to have been successfully adopted already in Turkey, Croatia, Dalmatia and Eastern Italy.