Philosophical Transactions. 327 



iron by muriatic acid, were insoluble in muriatic, nitric, nitro- 

 muriatic, and sulphuric acids. Infusible, but oxidated before the 

 blowpipe, especially by the aid of nitre. Their perfect solution 

 may be effected by the combined action of nitre and borax, since 

 the latter dissolves the oxide as fast as it is formed, and presents 

 a succession of clear surfaces, for fresh oxidation. But as these 

 salts do not unite by fusion, the addition of soda, as a medium of 

 union, shortens the process. The fused mass becomes opaque on 

 cooling by the deposition of a white oxide, which may either be 

 previously freed of the salts by boiling water, and then dissolved 

 in muriatic acid, or the whole mass may at once be dissolved 

 together. 



In either case alkalies precipitate from the solution a white oxide, 

 which is not soluble by excess of alkali, either pure or in a state 

 of carbonate. By evaporating the muriatic solution of the oxide 

 to dryness, at the heat of boiling water, it is freed of any redun- 

 dant acid, and the muriate which remains is perfectly soluble in 

 water, and in a state most favourable for exhibiting the charac- 

 teristic properties of the metal. Infusion of galls gives the well 

 known colour of gallate of titanium.— The colour occasioned by 

 triple prussiate of potash is also red, differing from prussiate of 

 copper, by inclining to orange instead of purple, while the colour 

 of prussiate of uranium is rather brown than red. 



Such experiments show in a concise and satisfactory manner 

 that the small cubic crystals are titanium, in its metallic state, 

 which is further proved by their being perfect conductors of very 

 feeble electricity. 



That titanium has no affinity for iron, seems evident from the 

 situation in which the above crystals occur, and " it seems," says 

 Dr. Wollaston, "equally indisposed to unite with every other 

 metal that I have tried." 



Its extreme infusibility renders it improbable that the cubes 

 should have formed during cooling from a state of fusion ; the 

 author thinks it probable that they have received their suc- 

 cessive increments by the reduction of the oxide dissolved in the 

 slag around them ; " a mode of formation," he observes, " to which 

 we must have recourse for conceiving rightly the formation in 

 nature of many other metallic crystals." 



3. On the Difference of Structure between the human Mcmhrana Tim- 

 pani and that of the Elephant. By Sir Evcrard Home, lit., V.P.R.S- 



In man the drum of the ear is circular, and its muscular fibres 

 form radii of equal lengths passing from the centre to the cir- 

 cumference ; in the elephant it is oval and the muscular fibres are 

 of unequal lengths, some being more than twice the length of 

 others. The fine sensibility of the human ear to musical sounds, 



