Abstract
For the last two years I have been using an electric furnace, and some facts which came under my notice on the occasion of a breakdown of the heating arrangement led me to suspect that platinum was not so entirely fixed at temperatures well below its melting-point as has been universally accepted by chemists and physicists. The electric resistance furnace used (fig. 1) is on the Heraeus system. It consists of a highly refractory porcelain tube, around which is coiled a ribbon of platinum foil, 11 mm. wide, 2∙8 metres long, and 0∙01 mm. thick, each convolution almost, but not quite, touching its neighbour. The ribbon closely enwraps the tubs, practically covering the surface to be heated, so that the heat produced by the passage of the electric current is immediately transmitted to the tube. The tubs is 4 cm. internal diameter; the object to be heated stands on a porcelain rod fixed upright in the middle of the tube. The body of the furnace is made to slide up and down by means of a windlass, so as to allow the crucible to be properly adjusted. The temperature of the furnace is measured by a Le Chatelier platinum and platinum-rhodium thermo-couple.

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