Page:Proceedings of the Royal Society of London Vol 4.djvu/362

Rh The Council has awarded the Copley Medal for the present year to Dr. G. S. Ohm, of Nuremberg, for his researches into the laws of Electric Currents, contained in various memoirs published in Schweigger's Journal Poggendorff's Annalen, and also in a sepa- rate work, entitled Die Galvanische Kette Mathematisch Bear- bitet, published at Berlin in the year 18^7. In these works, Dr. Ohm has established, for the first time, the laws of the electric cir- cuit ; a subject of vast importance, and hitherto involved in the greatest uncertainty. He has shown that the usual vague distinc- tions of intensity and quantity have no foundation, and that all the explanations derived from these considerations are utterly errone- ous. He has demonstrated, both theoretically and experimentally, that the action of a circuit is equal to the sum of the electro-motive forces divided by the sum of the resistances ; and that whatever be the nature of the current, whether voltaic or thermo-electric, if this quotient be equal, the effect is the same. He has also shown the means of determining with accuracy the values of the separate re- sistances and electro-motive forces in the circuit. The light which these investigations has thrown on the theory of current electricity is very considerable ; and although the labours of Ohm were, for more than ten years, neglected, (Fischner being the only author who, within that time, admitted and confirmed his views,) within the last five years, Gauss, Leng, Jacobi, Poggendorfi^, Henry, and many other eminent philosophers, have acknowledged the great value of his researches, and their obligations to him in conducting their own investigations. Had the works of Ohm been earlier known, and their value recognised, the industry of experimentalists would have been better rewarded. In this country those who have had most experience in researches in which voltaic agency is concerned, have borne the strongest testimony to the assistance they have derived from this source, and to the invariable accuracy with which the ob- served phenomena have corresponded with the theory of Ohm. This accordance, it may be observed, is altogether independent of the particular hypothesis which may be adopted as to the origin of elec- tro-motive force ; and obtains equally, whether that force is regarded as being derived from the contact of dissimilar metals, or as refer- able to chemical agency.

second series, vol. xiv.)
 * 1. On the electric conductibility of the metals. (Schweigger's Journal,

2. Experiments to discover the power of electro-magnetic multipliers. (Ibid. vol. XXV.)

3. Researches to ascertain the nature of unipolar conductors. (Ibid, vol, xxix.)

4. On hydro-electric currents. (Ibid, third series, vol. iii.)

5. Statement of facts destroying the relations which have been confu- sedly established between several galvanic properties, and particularly hydro-electric conductors. (Ibid. vol. v.)

6. Theory of galvanic currents. (Ibid, vol, vii.)