. The Philosophical magazine; a journal of theoretical, experimental and applied physics. ound them pronounced in otheriridio-platinum couples $. In the present couple slight irre-gularities between 350° and 450°, equivalent to about 5°, hadto be allowed for. When the range of temperatures is verylarge, the Avenarius-Tait equation is insufficient; but thisequation subserves a good purpose when interpolations be-tween two fixed temperature-data are called for, the data lyinganywhere on the scale, but not too far apart. Apparatus. 3. Boiling-points below 500° may be studied in a closedglass tube
. The Philosophical magazine; a journal of theoretical, experimental and applied physics. ound them pronounced in otheriridio-platinum couples $. In the present couple slight irre-gularities between 350° and 450°, equivalent to about 5°, hadto be allowed for. When the range of temperatures is verylarge, the Avenarius-Tait equation is insufficient; but thisequation subserves a good purpose when interpolations be-tween two fixed temperature-data are called for, the data lyinganywhere on the scale, but not too far apart. Apparatus. 3. Boiling-points below 500° may be studied in a closedglass tube, a a a a, fig. 1, within which a thin-walled tube, d d rf,open at both ends, passes coaxially quite through. In the * Bull. Geol. Survey, no. 54, p. 208 et seq., 1839. t Le Chatelier, /. c. I Bull. G. S. no. 54. pp. 80. 114 H seq., 1889. certain Hiyh-temperature Boiling-points. 143 bottom of the annular space between the tubes, the ebulhtionliquid, k k, is placed, and it is heated by Wolcott Gibbss ring-Fig. 1.—Longitudinal section of boiling-point tube. Scale 5 to \.. burner, r r. A conical asbestos screen, n n, protects theupper jiart of the tube from direct radiation. Other screens M2 144 Mr. Carl Barus on the Pressure-Variations of and jackets, p p p p, are suitably added. The upper end ofthe tube, aaaa, is in communication with the air-pump,through the lateral tubulure h. Finally, to obviate breakage,the lower end of the tube is protected by a metal jacket, m m. The thermocouple to be caHbrated, uo ^, is introduced intod d from below, and raised until the junction o is slightlyabove the plane of ebullition of the liquid, k k. The upperpart of the tube is closed with asbestos wicking (not shown)as far down as o. The wires of the couple pass throughparallel canals in a rod of fire-clay, xy, and are thus wellinsulated. The boiling-]>oints of most organic substances,mercury, sulphur, &c., are conveniently obtained in this way,provided the pressure be not to
Size: 1095px × 2283px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookids, bookpublisherlondontaylorfrancisetc, booksubjectphysics
