Curiosities of Science. 209 



and by using an electrical kite, he was able, in fine weather, to 

 produce decomposition, although so slowly that only rooWoth 

 of a grain of water was decomposed per hour. Faraday has 

 proved that the decomposition of one single grain of water pro- 

 duces more electricity than is contained in the most powerful 

 flash of lightning. 



ELECTRICITY IN BREWING. 



Mr. Black, a practical writer upon Brewing, has found that 

 by the practice of imbedding the fermentation- vats in the earth, 

 and connecting them by means of metallic pipes, an electrical 

 current passes through the beer and causes it to turn sour. As 

 a preventive, he proposed to place the vats upon wooden blocks, 

 or on any other non-conductors, so that they may be insulated. 

 It has likewise been ascertained that several brewers who had 

 brewed excellent ale on the south side of the street, on re- 

 moving to the north have failed to produce good ale. 



ELECTRIC PAPER. 



Professor Schonbein has prepared paper, as transparent as 

 glass and impermeable to water, which develops a very ener- 

 getic electric force. By placing some sheets on each other, 

 and simply rubbing them once or twice with the hand, it be- 

 comes difficult to separate them. If this experiment is per- 

 formed in the dark, a great number of distinct flashes may be 

 perceived between the separated surfaces. The disc of the 

 electrophorus, placed on a sheet that has been rubbed, pro- 

 duces sparks of some inches in length. A thin and very dry 

 sheet of paper, placed against the wall, will adhere strongly 

 to it for several hours if the hand be passed only once over it. 

 If the same sheet be passed between the thumb and fore-finger 

 in the dark, a luminous band will be visible. Hence with this 

 paper may be made powerful and cheap electrical machines. 



DURATION OF THE ELECTRIC SPARK. 



By means of Professor Wheatstone's apparatus, the Dura- 

 tion of the Electric Spark has been ascertained not to exceed 

 the twenty-five-thousandth part of a second. A cannon-ball, 

 if illumined in its flight by a flash of lightning, would, in 

 consequence of the momentary duration of the light, appear to 

 be stationary, and even the wings of an insect, that move ten 

 thousand times in a second, would seem at rest. 



VELOCITY OF ELECTRIC LIGHT. 



On comparing the velocities of solar, stellar, and terrestrial 

 light, which are all equally refracted in the prism, with the 



p 



