Art. LIX.—On a Convenient Form of Oil-bath for studying the Influence of Definite Temperatures on Solids.

By Dr.W. P. Evans.

[Read before the Philosophical Institute of Canterbury, 3rd November, 1897.]

This apparatus may be shortly described as a Meyer's bath, through the body of which, two tubes pass horizontally. The body measures 15 cm. long, 10 cm. broad, and 7·5 cm. deep, while each tube is of 2·5 cm. internal diameter. The first tube is open at both ends, but can be closed at one, if necessary, by means of a screw-cap and washer, the other end being turned to receive a cork. This tube, when closed by its cap, can be used at once as a small retort, or can, in the case of a substance which would attack copper, carry a tightly-fitting glass tube.

Trans. vert: section

Long vert: section

The second tube is, at one end, connected by a reducing-cap to a tube of 0·4 cm. bore, which re-enters the bath, is bent backwards and forwards twice inside the body, and leaves it on the same side as it enters. This tube, with its attached heating-coil, serves for drying at definite temperature in a current of gas already heated to that temperature before it reaches the drying-tube proper, or for distillation in steam or neutral gases.

A 12·5 cm. ball-condenser, with 0·5 cm. vapour space, enables a large Bunsen to be kept at full power under the bath without allowing a trace of vapour to escape. So perfect is the condensation, in fact, that with only a small flow of water through the ball, and water boiling hard in the bath, the free end of the condenser may be tightly corked, and so left without fear, thus preventing any contamination of the boiling liquid by dirt, &c.

As bath liquids, toluol, anilin, &c., may, of course, be used, and by fractionating the common harvester oils a fraction boiling near 400° C. may be easily obtained.

The accompanying figures give a longitudinal section