Chemical engineering . an abstract appearingin the London Electrician of May ig. The same furnace wasalso exhibited before the (British) Physical Society: an ab-stract of the latter paper may be found in the London Elec-trician of June 2. The furnace is designed for the attainment,in absence of noxious gases, of temperatures between 800° 2200° C. The conductor conveying the electric current is atube of solid electrolytes similar in composition to the filamentof a Nernst lamp. An essential feature is that for many pur-poses the usefulness and life of a furnace constructed in thisway may b
Chemical engineering . an abstract appearingin the London Electrician of May ig. The same furnace wasalso exhibited before the (British) Physical Society: an ab-stract of the latter paper may be found in the London Elec-trician of June 2. The furnace is designed for the attainment,in absence of noxious gases, of temperatures between 800° 2200° C. The conductor conveying the electric current is atube of solid electrolytes similar in composition to the filamentof a Nernst lamp. An essential feature is that for many pur-poses the usefulness and life of a furnace constructed in thisway may be much increased by adopting a cascade system ofheating: that is, the energy supplied may be divided, so thatonly sufficient is put through the tubular conductor to raise itstemperature, say, 1000 C. above its surrounding, the surround-ing itself being maintained at 1000° C, thus enabling a tem-perature of 2000° C. to be attained in the tube without strain-ing it unduly. The regulation of temperature in small fur-. FIG. I.—ELECTRIC naccs of this type is so perfectly under control that very well-defined melting points may be taktii with very small rjuantiticsof substance. The thermoelectric method has been used inthese furnaces for determining till- melting point of platinum,the mean result of the experiments giving 1710° C. within 5°.The furnace is shown in Fig. i. The arrangement consists ofan inner tube AB. formed of Nernst filament earths and heatedby a current at 200 to 500 volts, supplied by flexible platinumterminals. This tube is surrounded by a jacket of pure zir-conia, and that again by a fire-clay tube, kept at 1000° by means of a nickel coil CU. This ensures a uniform gradient of tem-perature. Chemistry of Electroplating.—In our Vol. II., page 389, wepublished in full \V. D. Bancrofts paper read before the Inter-national Electrical Congress in St. Louis, and developing atentative chemical theory of electroplating. This paper hasnow been enlarged
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