The Philosophical magazine; a journal of theoretical, experimental and applied physics . on wire, to which permanent strain Avasimparted by hammering transversely, by stretching longi-tudinally, or by bending the wire into coils of small all these experiments the thermoelectrical currents pro-duced by moderate heating were, as Sir W. Thomson hasalready found, from the strained to the unstrained throughthe hot junction, and in all there was a very sudden increaseof the current when, on being heated, the wire became brightred, and an equally sudden decrease when the wire wascooled. E
The Philosophical magazine; a journal of theoretical, experimental and applied physics . on wire, to which permanent strain Avasimparted by hammering transversely, by stretching longi-tudinally, or by bending the wire into coils of small all these experiments the thermoelectrical currents pro-duced by moderate heating were, as Sir W. Thomson hasalready found, from the strained to the unstrained throughthe hot junction, and in all there was a very sudden increaseof the current when, on being heated, the wire became brightred, and an equally sudden decrease when the wire wascooled. Experiment II. Two pieces of the same wire were arranged as in fig. 1 (p. 48).Aj Bi, Ag B2 are two wires brazed together at C and looped atAi,Bi and A2, Bj; from Bj and B^ the wires continue to D,where they are joined to the connecting wires of the galva-nometer G- ; D was well wrapped up in tissue-paper. Bi Si, 48 Mr. n. Tomlinson on the Thermoelectrical Properties Bg 83 aro pieces of strong string fastened at S], So to the ringof a retort-stand weighted at the bottom. From A^ passes. a string over a pulley P, and to the end of this string aweight of 1 kilo, was attached ; from A2 passes another stringto a support so as to hold up the portion A2C of the wire A2,Bg. The two wires Ai Bi, A2 B2 lie in the same horizontalplane ; to the left of C they are covered with sand from C to adistance of 10 centims. To the right of C for a distance ofabout 3 centims. the wires are bare, but beyond this forabout 7 centims. are covered with sand ; the sand is sus-tained on two stands placed to the right and left of C. First, the junction C was slightly heated b}^ a burner, andas the weight of 1 kilo, was not sufficient for the moderatetemperature then used to produce any sensible thermoelectricaleffect, the end Ai was pulled rather hard by the hand toascertain what would be the direction of the thermoelectiicalcurrent due to the stress ; this direction was found to be fromthe unstressed to the
Size: 2122px × 1178px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookids, bookpublisherlondontaylorfrancisetc, booksubjectphysics
