Intelligence and Miscellaneous Articles, 203 



As the amounts of deflexion varied with different parts of the 

 surface of the same bar, the surfaces of the bars were scraped quite 

 clean and the experiments with the amalgams Cd 12 Hg 10 , Cd 10 Hg 10 , 

 and Cd 10 Hg 12 repeated ; the same numbers as given above were 

 obtained. 



The numbers obtained in each case show a distinct depression of 

 strength of current with the amalgam composed of equivalent 

 weights of the two metals, similar to that obtained with halogens, 

 acids, and salts, and indicate that the two metals chemically unite 

 together in the proportions of their ordinary chemical equivalents. 

 The method may therefore probably be employed for the pupose of 

 detecting the chemical union of metals. 



ON THE SPECTRA OF THE ALKALIES. 

 BY PROF. H. KAYSER AND PROF. C. RUNGE. 



The investigation of the spectra of the alkalies has led us to 

 results which we present in the following short abstract. 



The spectra of the alkalies are formed in an entirely analogous 

 manner, which is especially manifest if, instead of the wave-lengths, 

 we consider the reciprocals — that is, the numbers of vibrations. 

 Each spectra is seen to be made up of several series of lines, each 

 of which may be represented with great accuracy by the formula 



X n~ iv 



where X is the wave-length, A, B, and C are three constants, and 

 n stands for the series of whole numbers from n = 3 upwards. For 

 n=2 the formulae give in all cases negative— that is, impossible 

 numbers of vibrations; ?i==3 represents the fundamental vibra- 

 tions. 



The lines of the various series of each element behave very 

 differently as regards visibility, widening out with increase of 

 vapour-density. In each element we find one chief series which 

 contains the strongest lines, those which appear most easily, and 

 those which are most easily reversible ; it extends in all cases from 

 the red end of the spectrum to the extreme ultra-violet. The 

 members of the principal series, M'ith the exception of lithium, are 

 with all alkalies pairs, whose distance is less as the wave-length 

 increases; we have found that the difference of the numbers of 

 vibrations for the two lines of each pair is inversely proportional to 

 the number of this pair, that is of the value n, which, when inserted 

 in the formula, gives the pair. 



Besides the chief series, all alkalies have accessory series which 

 essentially appear in the visible part of the spectrum. In lithium 

 there are two secondary series, and in sodium four, each two of 



