The Annals of Electricity, Magnetism, and Chemistry Volume 10; And Guardian of Experimental Science (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1843 Excerpt: ...of r in the formula, we might compare, in a similar manner, as pointed out by Professor Wheatstone, the results of two arrangements, in which the electromotive forces being equal, the resistances in the cells alone should vary. As, however, from the complicated nature of the arrangements, and the variability of different influential circumstances to which I have before alluded, I found it impossible to obtain two perfectly unexceptionable results for the comparison, I thought it allowable to take the mean of several; and from this I found that, with a voltameter whose platinum plates are three inches in length, by one inch in width, a quarter of an inch apart, and charged with the standard dilute sulphuric acid, (sp. gr. 1126), r--0541 R in a constant battery of the dimensions just described. Now if a single cell of such a battery be taken and the circuits closed by a short thick wire, and the zinc rod forming the generating plate of the arrangement, be weighed at intervals of five minutes, it will be found to lose 11 26 grs. for every such interval. This is a measure of the effective force of the circuit; and its equivalent in mixed gases is twenty-five cubic inches. This will be /E taken as the unit of work in the Table that follows, i. e. f--= 1 V and the calculated results for the different combinations will, in the third and fourth columns, be represented in fractions of this unit. It is evident, that the amount of zinc, dissolved in such a single circuit, furnishes a measure of the maximum work that any number of such cells, combined in a single series, would be capable of per E n E E forming; for-= A, and can never be greater than--, R n R + r R however great the value of n may be, so long as r has a positive value. In other words, however great the ...