On some Phenomena of Induced Electric Sparks, 191 



passing through gross bodies. I have on several previous 

 occasions treated of the problem of gravitating force theoreti- 

 cally, and by slow steps have approximated to its solution ; 

 but before the present attempt, I had not succeeded in 

 exhibiting satisfactorily the rationale of this kind of attraction 

 by vibrations. 



26. In concluding this communication, I beg to call the 

 attention of mathematicians to the different applications I have 

 made of those laws of the mutual action of the parts of an 

 elastic fluid which for brevity I call spontaneous vibrations. 

 The mathematical theory of these vibrations I gave first in 

 the Philosophical Magazine for May 1849 ; afterwards I ap- 

 plied them in accounting for the polarization of light in the 

 undulatory theory (Philosophical Magazine for December 1852, 

 and ' Principles of Physics,' pp. 331-338) ; and in the present 

 communication I have shown that they constitute an essential 

 part of the a priori theory of music, and that it is necessary to 

 introduce them in hydrodynamical theories of atomic repulsion 

 and molecular att?*action. Apart from the argument which I 

 have elsewhere insisted upon, that these vibrations have been 

 arrived at by logical deduction from the premises of hydro- 

 dynamics, the fact of their being capable of application in 

 theories so various in kind and important in character as those 

 above mentioned ought, I think, to be regarded as confirmatory 

 of their truth. 



Cambridge, July 22, 1876. 



XXIV . On some Phenomena of Induced Electric Sparks. 

 By S. P. Thompson, B.A., B.Sc* 



[Plate II.] 



1. npHE observations communicated in this paper are the 

 J- result of an investigation into the phenomena dis- 

 covered in November 1875, in Newark, N. J.,by Messrs. T. A. 

 Edison and C. Batchelor, and alleged to demonstrate the ex- 

 istence of a new form of energy. A detailed memoir of the 

 phenomena has since appeared in the ' Quarterly Journal of 

 Science ' f, by Dr. G-. M. Beard, of New York, who accepts, 

 with some hesitation, the hypothesis of a new force. 



2. When a galvanic current passing through the coils of an 

 electromagnet is rapidly interrupted, minute bright sparks 

 can, at the moment of interruption, be drawn from the electro- 



* Communicated by the Physical Society. 



t " The newly-discovered Force," by George M. Beard, A.M., M.D., 

 New York (Quarterly Journal of Science, No. L. April 1876). 



