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XXV.—Thermo-Electric Diagram from −200° C. to 100° C., deduced from the observations of Professors Dewar and Fleming

Published online by Cambridge University Press:  06 July 2012

J. D. Hamilton Dickson
Affiliation:
Peterhouse, Cambridge.

Extract

In 1895 Professors Dewar and Fleming made an extensive and careful series of observations connecting temperature and the thermo-electromotive force of some twenty metals compared with lead. The greatest care was taken in the preparation for, and in the conduct of, the experiments, and about thirty readings, at temperatures ranging over the 300° between the boiling point of oxygen and the boiling point of water, were recorded for each metal. A full description of the mode of experimenting, with the results for each metal, was published in the Philosophical Magazine, July 1895. In their discussion of the results a further examination of them was promised, but has not appeared. Professor Fleming, however, in a Friday Evening Discourse at the Royal Institution in 1896, indicated that the lines of thermo-electric power did not appear as straight lines although they were approximately so.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1911

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References

page 737 note * Phil. Mag., Ser. V., vol. xl. pp. 95–119.

page 740 note * Phil. Mag., Ser. V., Vol. xliv. p. 445; and Vol. xlv. p. 525.

page 750 note * The photographic reduction has rendered this displacement not visible in fig. 6. See Note, p. 788.

page 764 note * H' is measured from an origin arbitrarily placed 250 below the axis of temperature, for convenience.

page 774 note * See Note, p. 788.

page 778 note * Suppose a quantity x were to be determined from two numbers such as 542·3 and 548·7, each of which could be depended on to one-tenth per cent., i.e. they might lie between 541·8 and 542·8, and 548·3 and 549·2; and suppose that x depended on their difference. This difference, therefore, might vary from 549·2–541·8 to 548·2 – 542·8—that is, from 7·4 to 5·4. Thus an error of inappreciable amount on the numbers themselves might cause a difference on the values from which x was to be determined of from 25 to 33 per cent.

page 779 note * See Note, p. 788.

page 785 note * Wied. Ann., xlvii. (1892), pp. 107–134.

page 785 note † Phil. Mag., Ser. V., vol. xxxiv, pp. 1–18.