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See also:JOULE, See also:- JAMES
- JAMES (Gr. 'IlrKw,l3or, the Heb. Ya`akob or Jacob)
- JAMES (JAMES FRANCIS EDWARD STUART) (1688-1766)
- JAMES, 2ND EARL OF DOUGLAS AND MAR(c. 1358–1388)
- JAMES, DAVID (1839-1893)
- JAMES, EPISTLE OF
- JAMES, GEORGE PAYNE RAINSFOP
- JAMES, HENRY (1843— )
- JAMES, JOHN ANGELL (1785-1859)
- JAMES, THOMAS (c. 1573–1629)
- JAMES, WILLIAM (1842–1910)
- JAMES, WILLIAM (d. 1827)
JAMES See also:PRESCOTT (1818–1889) , See also:English physicist, was See also:born on the 24th of See also:December 1818, at See also:Salford, near See also:Manchester. Although he received some instruction from See also:John See also:Dalton in See also:chemistry, most of his scientific knowledge was self-taught, and this was especially the See also:case with regard to See also:electricity and electro-See also:magnetism, the subjects in which his earliest researches were carried out. From the first he appreciated the importance of accurate measurement, and all through his See also:life the attainment of exact quantitative data was one of his See also:chief considerations. At the See also:age of nineteen he invented an electromagnetic See also:engine, and in the course of examining its performance dissatisfaction with vague and arbitrary methods of specifying See also:electrical quantities caused him to adopt a convenient and scientific unit, which he took to be the amount of electricity required to decompose nine grains of See also:water in one See also:hour. In 184o he was thus enabled to give a quantitative statement of the See also:law according to which See also:heat is produced in a conductor by the passage of an electric current, and in succeeding years he published a See also:series of valuable researches on the agency of electricity in transformations of See also:energy. One of these contained the first intimation of the achievement with which his name is most widely associated, for it was in a See also:paper read before the See also:British Association at See also:Cork in 1843, and entitled " The Calorific Effects of Magneto-electricity and the See also:Mechanical Value of Heat," that he expressed the conviction that whenever mechanical force is expended an exact See also:equivalent of heat is always obtained. By rotating a small electro-magnet in water, between the poles of another magnet, and then measuring the heat See also:developed in the water and other parts of the See also:machine, the current induced in the coils, and the energy required to maintain rotation, he calculated that the quantity of heat capable of warming one See also:pound of water one degree F. was equivalent to the mechanical force which could raise 838 lb. through the distance of one See also:foot. At the same See also:- TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
- TIME, MEASUREMENT OF
- TIME, STANDARD
time he brought forward another determination based on the See also:heating effects observable when water is forced through capillary tubes; the number obtained in this way was 770. A third method, depending on the observation of the heat evolved by the mechanical See also:compression of See also:air, was employed a See also:year or two later, and yielded the number 798; and a See also:fourth—the well-known frictional one of stirring water with a sort of paddlewheel—yielded the result 890 (see Brit. Assoc. See also:Report, 1845), though 781.5 was obtained by subsequent repetitions of the
experiment. In 1849 he presented to the Royal Society a memoir which, together with a See also:history of the subject, contained details of a See also:long series of determinations, the result of which was 772. A See also:good many years later he was entrusted by the See also:committee of the British Association on See also:standards of electric resistance with the task of deducing the mechanical equivalent of heat from the thermal effects of electric currents. This inquiry yielded (in 1867) the result 783, and this Joule himself was inclined to regard as more accurate than his old determination by the frictional method; the latter, however, was repeated with every precaution, and again indicated 772.55 foot-pounds as the quantity of See also:work that must be expended at See also:sea-level in the See also:latitude of See also:Greenwich in See also:- ORDER
- ORDER (through Fr. ordre, for earlier ordene, from Lat. ordo, ordinis, rank, service, arrangement; the ultimate source is generally taken to be the root seen in Lat. oriri, rise, arise, begin; cf. " origin ")
- ORDER, HOLY
order to raise the temperature of one pound of water, weighed in vacuo, from 6o° to 61° F. Ultimately the discrepancy was traced to an See also:error which, not by Joule's See also:fault, vitiated the determination by the electrical method, for it was found that the See also:standard See also:ohm, as actually defined by the British Association committee and as used by him, was slightly smaller than was intended; when the necessary corrections were made the results of the two methods were almost precisely congruent, and thus the figure 772.55 was vindicated. In addition, numerous other researches stand to Joule's See also:credit—the work done in compressing gases and the thermal changes they undergo when forced under pressure through small apertures (with See also:Lord See also:Kelvin), the See also:change of See also:volume on See also:solution, the change of temperature produced by the See also:longitudinal See also:extension and compression of solids, &c. It was during the experiments involved by the first of these inquiries that Joule was incidentally led to appreciate the value of See also:surface condensation in increasing the efficiency of the See also:steam engine. A new See also:form of See also:condenser was tested on the small engine employed, and the results it yielded formed the starting-point of a series of investigations which were aided by a See also:special See also:- GRANT (from A.-Fr. graunter, O. Fr. greanter for creanter, popular Lat. creantare, for credentare, to entrust, Lat. credere, to believe, trust)
- GRANT, ANNE (1755-1838)
- GRANT, CHARLES (1746-1823)
- GRANT, GEORGE MONRO (1835–1902)
- GRANT, JAMES (1822–1887)
- GRANT, JAMES AUGUSTUS (1827–1892)
- GRANT, ROBERT (1814-1892)
- GRANT, SIR ALEXANDER
- GRANT, SIR FRANCIS (1803-1878)
- GRANT, SIR JAMES HOPE (1808–1895)
- GRANT, SIR PATRICK (1804-1895)
- GRANT, U
- GRANT, ULYSSES SIMPSON (1822-1885)
grant from the Royal Society, and were described in an elaborate memoir presented to it on the 13th of December 186o. His results, according to Kelvin, led directly and speedily to the See also:present See also:practical method of surface-condensation, one of the most important improvements of the steam engine, especially for marine use, since the days of James See also:Watt. Joule died at See also:Sale on the 11th of See also:October 1889.
His scientific papers were collected and published by the See also:Physical Society of See also:London: the first volume, which appeared in 1884, contained the researches for which he was alone responsible, and the second, dated 1887, those which he carried out in association with other workers.
End of Article: JOULE, JAMES PRESCOTT (1818–1889)
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