44) Mr. Laming ow the primaty Forces of Electricity. 



limited to certain constant multipliers ; but tlie combined re- 

 sult of some three or four of these are sometimes concerned 

 in giving a single solution on the scale of geometric equiva- 

 lents, and that in a novel and curious manner. 



The multipliers selected possess an extensive range, and 

 include the elements of most of the calculations likely to be 

 called for ; the mode to be pursued can scarcely be mistaken, 

 as the simple names of the functions serve to indicate the 

 proceeding in each case; and when a little arithmetic and 

 the tables of squares and cubes are brought in to assist, the 

 powers of the contrivance are exceedingly increased. We 

 exchange the tediousness of calculation and the errors which 

 creep in, notwithstanding every care, for the certainty of the 

 relations of the lines; subject however to the error of read- 

 ing, which will not in general be found an inadmissible quan- 

 tity; it rarely equals the one hundredth part of the totals, 

 and is sometimes within the thousandth part of the same. 

 The answers given in this paper were obtained from the 

 instrument alone: their proof by calculation, (in which the 

 formulae on the scales will assist,) will show the degree of 

 reliance that may be placed on the method. 



Of course such scales might be adapted to a variety of other 

 investigations, and they would be made to any given data. 



In order to lessen the expense of the present instrument, I 

 propose to graduate the scales on copper-plate* and to print 

 from them. 1 should therefore feel obliged by any suggestions 

 calculated to improve the arrangement proposed previously 

 to so doing. 



I remain. Sir, your most obedient servant, 



64, Charing Cross, London, C. Holtzapffel. 



June 6th 1838. 



IX. On the primarij Forces of Electricity. By Richard , 

 Laming, Esq., M.R.C.S. 



[Continued from p. 498.] 



32. \irE may now apply the principle of compensation to 

 ' ' some of the leading phaenomena attendant on the ac- 

 cumulation of free electricity in rarified air. As the quantities 

 susceptible of being accumulated in conductors under atmo- 

 spheric compensation have been shown, both theoretically 

 and experimentally, to vary in the simple ratio of the density 

 of the air, the quantity that is communicable firom one body 



•As explained in the pamphlet, the error of contraction after printing is 

 immaterial with the proportional scales; it is only inadmissible in such as 

 demand an agreement with the standard measure, pp. 6 and 7. 



