Open AccessThe effects of temperature and pressure on the thermal conductivities of solids. Part II.—The effect of low temperatures on the thermal conductivities of pure metals and alloys
Author(s) -
Charles H. Lees
Publication year - 1908
Publication title -
proceedings of the royal society of london. series a, containing papers of a mathematical and physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9150
pISSN - 0950-1207
DOI - 10.1098/rspa.1908.0008
Subject(s) - brass , copper , materials science , tube (container) , thermal , thermal conductivity , composite material , electromagnetic coil , heat exchanger , metal , metallurgy , thermodynamics , electrical engineering , physics , engineering
The object of the work described in the present paper was to extend the measurements of Thermal Conductivities of Metals and Alloys made by Lorenz, Jäger and Diesselhorst, and others at temperatures between 0°C. and 100°C. down to the temperature of liquid air, and thus provide a means of comparing the Thermal and Electrical Conductivities of these substances over a much wider range of temperature than has hitherto been possible. The method adopted was a modification of that used originally by Wiedemann and Franz. A rod of the metal, 7 or 8 cm. long, 0∙6 cm. in diameter, was placed in the axis of a vertical copper tube of 2∙7 cm. internal 3∙3 cm. external diameter, 9∙5 cm. long, closed at the top. The lower end of the rod fitted into a copper disc, which in its turn fitted into the lower end of the copper tube. The joints were accurately made and were smeared with olive oil to exclude air and improve the thermal contact. The heat which flowed along the rod was supplied electrically by means of a current through a fine platinoid wire wound on a short thin brass sleeve, which was slipped on to the upper end of the rod. The difference of temperatures at two points of the rod, between the heating coil and the point where the rod entered the disc forming the lower end of the tube, was measured by means of two platinum thermometers, the wires of which were wound on two short thin brass sleeves, capable of sliding along the rod. The three sleeves fitted the rod closely, and thermal contact was improved by smearing rod and sleeves with a little olive oil.