183 



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. Mr. 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. 



Experiments on Wootz. By Mr. David Mushet. Communicated by 

 the Right Hon. Sir Joseph Banks, K.B. P.R.S. Read February 

 14, 1805. {Phil. Trans. 1805,^. 163.] 



The fine cakes of the kind of steel called Wootz, which form the 

 subject of the present paper, were delivered to Mr. Mushet, 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. Mushet 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- 



