Page:Proceedings of the Royal Society of London Vol 1.djvu/203

Rh having found, from several experiments, that a red heat is not sufﬁ- cient to expell all the matter capable of being volatilized.

Mr. Davy then made some experiments to determine whether any portion of ﬁxed alkali existed in this mineral, but no indications of such alkali could be observed. ’

The ﬂuid obtained by distilling several different specimens of this mineral was similar in its properties; the only test of the presence» of acid matter in it was litmus paper; and in some instances the ef- fect upon this paper was scarcely perceptible. IMr. Davy made se- veral experiments to determine the nature of the above acid matter, but Without success.

It is, however, he says, evident that it is not any one of the known mineral acids: he is also disposed to believe, that it is not an essen- tial component part of- the mineral, but that, as well as the oxide of manganese, the oxide of iron, and the lime, it is only an accidental ingredient. Hence the mineral, when in a state of purity,'must, he thinks, be considered as a chemical combination of about 30 parts of water, and 70 of alumine.

The diaspore, which has been examined by M. Vauquelin, loses 16 or 17 parts in the 100 by ignition, and contains nearly 80 parts of alumine, and 3 of oxide of iron. It is supposed by M. Vauquelin to be a compound of alumine and water. But its characters are very different from those of the mineral here described; and the nature of the part volatilized by heat has not yet been ascertained.

A mineral similar to that here treated of has been found near St. Austle in Cornwall ; and Mr. Davy has been informed that, according to an analysis of it made by the Rev. William Gregor, it appears to consist of similar ingredients.

Dr. Babington has proposed to call this mineral by the name of Wavellite, from the gentleman who discovered it in Devonshire; but if a name founded upon its chemical composition should be preferred, Mr. Davy thinks it may be denominated Hydrargillite.

The fine cakes of the kind of steel called Wootz, which form the subject of the present paper, were delivered to Mr. Musbet, for the purpose of examination, by Sir Joseph Banks. Mr. Mushet begins his account of them by giving a very minute description of the form, the grain, and every other external character of these cakes. This description cannot well be abridged, and is too long to be repeated. We shall therefore only say that Mr. Musbet states, as a general remark, that the grain and density of these cakes of wootz were uni- formly homogeneous, and free from metallic iron towards the under or round surface, but that they were always the reverse towards the upper side, called by Mr. Mushet the feeder.

The appearances observed upon forging these cakes are then par.