RECTIFICATION OF ETHER, a process for de-
SUPPL. VOL. II. Part I.
priving ether of its sulphureous acid (See CHEMICAL INDEX in this Suppl.) It has been usual to add an alkali for this purpose; but Dize has found it much more advantageous to add a substance which might afford the requisite quantity of oxygen to convert the sulphureous into the sulphuric acid; in which state it is not disposed to rise and come over. Various metallic oxyds were tried, among which the black oxyd of manganese proved the best and the cheapest. His process is as follows:
The sulphureous acid contained in unrectified ether being neutralized with oxyd of manganese, the fluid is decanted into a pewter vessel of the capacity of fifty ounces, which is placed on a water bath. To this vessel a head and worm are adapted, the latter of which passes through a refrigeratory constantly supplied with water in a stream from below, which causes the heated water to flow off above. The distillation is then performed by raising the bath to a temperature of 36° (113° Fahrenheit, if the decimal thermometer be here meant). The rectification by this treatment usually requires a day to complete it. The flavour of the ether is of the best kind, and the product about one-sixth more than in the usual method with retort and receiver. Dize has practised this method with success for three years.—Journal de Physique, April, 1798.