HISTORY OF ELECTRICAL RESONANCE 417 



motion between the coatings, in oscillations which become continually smaller 

 until the entire vis viva is destroyed by the sum of the resistances. The notion 

 that the current of discharjje consists of alternately opposed currents is favored 

 by the alternately opposed mafjnetic actions of the same; and secondly by the 

 phenomena observed liy WoUaston while attemptinj^ to decompose water by elec- 

 tric shocks, that l)oth descriptions of gases are exhibited at l)oth electrodes."^ 



It may be interesting to note in passing lliat this now famous memoir by 

 Helmholtz on the conservatioii of energy was considered so advanced and 

 speculative as to be refused publication in the leading (Jerman scientific 

 journal of the time. In it there was set forth, with far more thoroughness 

 and generality than had been done before (by Mayer and Joule, for instance), 

 the theorem that in any closed system the sum total of the energy is con- 

 stant; a principle that at once denies the possibility of perpetual motion. 

 It was privately published in pamphlet form in 1847. Its author, later to be 

 recognized as the greatest (lerman physicist of the century, was then an 

 obscure Ypung army surgeon, just twenty-six years of age. 



By this time, it can be assumed from the foregoing, it was generally 

 accepted by the learned in electrical science that the spark of a Leyden jar 

 discharge was an oscillatory motion of electricity. This conclusion was 

 arrived at as a logical and reasonable deduction from the results of various 

 experiments, although the mode of action was still obscure. It was time 

 now for a more analytical examination of the subject, and this was soon to 

 appear. 



In 1853 the British physicist Sir William Thomson, afterwards Lord 

 Kelvin, published a paper with the title ''On Transient Electric Currents,"'* 

 which, like that of Helmholtz, became in time a classic. In this paper the 

 generalized problem of the discharge of a condenser through a conductor 

 was treated mathematically. In addition to resistance and capacity he 

 recognized the efifect of inductance (called by him the "electrodynamic 

 capacity") upon the discharge, and established an equation expressing the 

 fact that the energy of the charged condenser at any instant during discharge 

 is partly being dissipated as heat and partly conserved as current energy 

 in the circuit; his equation being, in present day terminology, 



an equation thai is easily solved. He anal)/,e<l the \ari()us solutions, which 

 depend upon the relative values of the constants, or their ratios, and 

 showed that under certain conditions the discharRe is unidirectional and 



