Intelligence and Miscellaneous Articles. 391 



of work which can be exerted by a certain quantity of electricity ; for 

 the tension is diminished by a certain amount. According to Weber 

 and others, a milligramme of water is decomposed by 107 units of 

 current in a second, and therefore by 107 units of electricity. If we 

 denote by N the number of molecules contained in a milligramme, 

 and by e the quantity of electricity which each must receive and give 

 up in order to be decomposed, then 



N<?=107. 



Further, according to Bosscha, the electromotive force of a Da- 

 rnell's element in electromagnetic units (or, what is the same thing, 

 the tension of the positive pole of such an element whose negative 

 pole is connected with the earth) is equal to 



10258 XlO 7 , 



a number which may also be deduced from Favre and Silbermann's 

 experiments. The decomposition of water requires a tension 1*46 

 as great ; if this is denoted by P, we have 



P=15xl0 10 . 



Let us suppose that the molecule of water has a tetrahedral arrange- 

 ment, then 



a 3 



in which d is the distance of two adjacent molecules of water, and 

 the quantity of electricity e which a molecule has received must some- 

 how have spread inside a spherical surface the diameter of which is 8. 

 The work e corresponding to this quantity of electricity will have now 

 its smallest value if the electricity is uniformly diffused over the sur- 

 face of this sphere ; for any other arrangement of the electricity would 

 require an increased work. The tension corresponding to this order 

 will be 



2a 2 e 



and this magnitude must therefore be smaller than the actual tension 

 P resulting from another distribution of the same quantity of elec- 

 tricity. Thus we get 



?^!f<P. 



From these equations we find 



N< 1360 X 10 19 and B < -^ millim. 



