5
This is the same as saying that the resistance (in the modern sense) varies as the
0.08, 0.03, -0.024
power of the strength of the current in the first three sets of experiments, and in the fourth set, that it does not vary at all.
This result, obtained by Cavendish in January, 1781, is an anticipation of the law of electric resistance discovered independently by Ohm, and published in 1827. It was not until long after the latter date that the importance of Ohm's law was fully appreciated, and that the measurement of electric resistance became a recognized branch of research.
The exactness of the proportionality between the electromotive force and the current in the same conductor seems, however, to have been admitted, rather because nothing else could account for the consistency of the measurements of resistance obtained by different methods, than on the evidence of any direct experiments.
Some doubts having been suggested with respect to the mathematical accuracy of Ohm's law, the subject was taken up by the British Association in 1874, and the experiments of Professor Chrystal, by which the exactness of the law, as it relates to metallic conductors, was tested by currents of every degree of intensity, are contained in the report of the British Association for 1876.
The laws of the strength of currents in multiple
