Abstract
MR. DAY has produced a new and considerably improved edition of a most useful and valuable little book. Every teacher of electricity whose work is not confined to the beggarly elements of mere phenomena will thank Mr. Day for tne admirable selection of problems put together in this volume. Nothing could be a greater boon to the real student than the means thus afforded of testing his knowledge of the exact quantitative laws of the science. If it were not for the historic interest of that rather anti-quated instrument the torsion balance — we should doubt the utility of giving so much attention to it. Although the more modern electrometers have entirely superseded the torsion balance as an instrument of research and of measurement, it has, nevertheless, become so prominently fixed—like some grand old fossil long ago extinct — amongst the characteristic forms of electrical instruments that examiners still expect candidates for examination, to know something about it. On the other hand, the space allotted to moments of torsion and inertia is all too brief,though admirably filled. We must, however, take exception to the practice apparently followed on p. 62, of expressing a moment of couple in dynes: it should surely be dyne-centimetres. The section on the chemical (or rather thermo-chemical) theory of electromotive force is excellent. The problems comprised under the heading Electromagnetic Measurement are admirable, though perhaps a little beyond most students.
Exercises in Electrical and Magnetic Measurement.
By R. E. Day New Edition. (London: Longmans, Green, and Co., 1884.)
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Exercises in Electrical and Magnetic Measurement . Nature 31, 262 (1885). https://doi.org/10.1038/031262a0
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DOI: https://doi.org/10.1038/031262a0