concerned in the Phenomena of ordinary Electricity, &;c. 291 



jars, equal to a powerful flash of lightning, would be necessary 

 to resolve a single grain of water into its elements is certainly 

 astounding, when it is recollected that, according to Faraday*, 

 the quantity of electricity that decomposes a body is the equiva- 

 lent quantity of electricity that had previously held the elements 

 of that body in combination ; for he, with Davy and others, 

 conceives that electricity and chemical affinity are identical 

 powers. Hence in one grain, that is, one drop of water, there 

 must be, naturally existing and constituting the affinity between 

 its oxygen and hydrogen, no less a quantity of electricity than 

 800,000 charges of a battery containing 3510 square inches of 

 coated glass, or the equivalent of " a very powerful flash of light- 

 ning." If this quantity of electricity were converted into one 

 spark, it would be 4166 miles in length, taking Professor Fara- 

 day's mean estimate of one charge of his battery as the basis of 

 calculation. Can this exist in a drop of water ? 



Faraday's expressed opinion on this subject is not an hyper- 

 bole, intended to exalt the conception of the quantity of elec- 

 tricity in the drop : he means it literally, and the admission of 

 it is necessary to the alleged identity of common and voltaic 

 electricity. Who that has heard a near clap of thunder, which 

 makes the very ground on which he stands tremble, or that has 

 seen the awful flash which prostrates buildings, melts masses of 

 iron, strikes deep cavities in the earth, and kills the largest 

 animals, can reconcile to himself that the cause of all this de- 

 struction is contained in a drop of water ? 



With regard to the quantity of ordinary electricity necessary 

 for the decomposition of a certain quantity of water, there are 

 other estimates on record which it may be proper to compare 

 with those of Faraday, as they arc founded on experiments con- 

 ducted with great attention to accuracy, and with immense labour. 

 In 1789, a set of experiments was published by the associated 

 Dutch chemists, MM. Paets Van Troostwyk, and Deimant. 

 By passiug 600 discharges of ordinary electricity, from a jar 

 containing one square foot of coated surface, through a slender 

 tube containing distilled water previously freed from air, they 

 obtained, in the only experiment exactly stated by them, a quan- 

 tity of mixed oxygen and hydrogen, which stood three-eighths of 

 an inch high in a tube one-eighth of an inch in diameter English 

 incisure. Whoever will take the trouble of the calculation will 

 find, that at this rate, in order to decompose a grain of water, 

 no less than 1,033,702 such discharges would be required. But 

 as these were discharge! from a jar containing one foot only of 

 Boated sui-tacr, whereas Professor Faraday's discharges were from 

 24*4 square feet, when the former arc converted into the latter, 



* Researches, par. s'i2. f Journal dc Physique, vol. xxxv. p. 369. 

 U2 



