IN my first paper on this subject the behaviour of soft iron, steel, copper, and platinum was examined. In this paper the experiments have been carried a stage further, viz. the reaching of the cyclically steady state with a small load, the effect when the load is increased, and the heating by the ordinary method.

As the behaviour of the wire when heated by the current was somewhat complicated, I considered it necessary, for purposes of comparison, to heat the wire in some other manner. To effect this, a double-walled tube of tinned iron was made, through the inner tube of which the wire was passed, and the ends plugged with cotton-wool. The wire was horizontal, and measurements were made with the microscopes as in the other experiments.

MY last communication in reference to the history of general determinants dealt with the period 1844–1852 (Proc. Roy. Soc. Edin., xxv. pp. 908–947). The present paper continues the history up to 1860, but in addition contains an account of five writings belonging to previous periods, namely, by Bianchi (1839), Chelini (1840), Terquem (1846), Hermite (1849), Salmon (1852).

WHEN a mixture of ethyl alcohol, benzene, and water is fractionated, a ternary mixture of all three distils over first at a temperature of 68°C.

Taylor has made use of this fact in the preparation of the ethyl esters of high boiling-point acids.

His method is a great improvement on the old methods, but it is not continuous, and is tedious when large quantities of ester have to be prepared.

To remedy these defects the apparatus described in this paper was devised.

IN the ordinary methods for the preparation of tartaric acid dinitrate, a mixture of fuming nitric acid with concentrated sulphuric acid is used as a nitrating agent.

The product is treated with iced water to remove the sulphuric and nitric acids.

As the dinitrate is decomposed by water, even at 0° C, it is impossible to avoid some loss in this process.

By using nitric anhydride as a nitrating agent this difficulty is avoided. Nitric acid, which is the only other product of the reaction, can be removed by evaporation in vacuo.

The process of Dennstedt for the elementary analysis of organic compounds by combustion in oxygen with the help of platinised quartz was tried in this laboratory, and in expert hands was found to be both rapid and accurate. The average student, however, experienced great difficulty in the conduct of the combustion, and it occurred to us that the advantages of the apparatus of Dennstedt, so carefully worked out by him in detail, might be applied to the ordinary method of combustion by means of copper oxide.

If one inspects a tube in which a copper oxide combustion is being conducted, it is found that the oxide actually reduced to metallic copper, after the combustion of the volatile matter is completed, rarely extends for more than an inch or two along the tube, unless the process has been accidentally “rushed.”