Menachanite. Ferriferous Oxide of Titanium

We are indebted for the first discovery of this curious substance to the penetration of our ingenious friend the Rev. Mr. Gregor, who examined it in the year 1783, and discovered that besides Iron, it contained a new metal, which he called Menachine, but which appears to have been the same with what has since been discovered in the Red Schorl by Klaproth, and is named Titanium. This name has obtained most general use, on account of the great authority of the chemist by whom it was given, although Menachine might with much propriety have been preferred , as being originally given to the substance by Mr. Gregory he being undoubtedly the first who named it, as well as the first discoverer of it. The term Menachanite has been applied to the substance here figured from the name of the place where it was first found, the valley of Menachan, in Cornwall. The same substance is said to have been since met with in the Island of Providence and in New Holland. It bears some resemblance to gunpowder, but has rather more the appearance of grains of Plumbago. The grains do not assume any particular shape, some being flattish and angular, and others finely granulated. Menachanite is easily pulverized, is rather brittle, and slightly attractable by the magnet. Its surface is opaque, somewhat shining, grayish black, retaining its colour when pounded, in which it differs from the Iron Sand of tab. 197.

By analysis, Mr. Gregor found it to contain

Among the loss a little Silica and Oxide of Manganese are included. A trifle of Oxide of Manganese, Silica, and Alumina have been found since in some specimens by other persons; but as these may be reckoned rather adventitious, Mr. Gregor’s seems most to be depended upon. Klaproth, Hecht, and Vauquelin have clearly proved Mr. Gregorys accuracy by their analyses.

Spec. Grav. 4.427.

The Oxide of Titanium, when separate from the other ingredients of the Menachanite, has these peculiar properties. It may be reduced by exposing it with charcoal to a violent heat, when it assumes a deep copper colour, with much lustre and brittleness, but is elastic when in thin plates. It is extremely difficult of fusion. It is easily tarnished by air, or oxidized by heat, becoming blue, and detonates when thrown on hot Nitre. It is said to form three Oxides, viz. the blue or purple, the red, and the white.

We, as well as Haüy, consider the Nigrine of Karsten as a variety of Menachanite, but generally much freer from Iron.