174 ANNUAL OF SCIENTIFIC DISCOVERY. 



cent, of residue remains behind, which is graphite in fine scales. 

 Again, when the crystals are powdered, mixed with hydrate of potash 

 and fused, ammonia and titanate of potash are formed. When the 

 crystals are heated to redness in a porcelain tube, and steam is passed 

 over them, a considerable quantity of hydrogen gas is liberated, to- 

 gether with a disengagement at the same time of ammonia and hydro- 

 cyanic acid. With regard to the formation of the crystals in the 

 smelting furnace, Wohler believes that it stands in intimate connec- 

 tion with the formation of cyanide of potassium ; and experiments 

 fully confirm the supposition. A mixture of ferrocyanide of potas- 

 sium and titanic acid was exposed in a well-closed crucible, for an 

 hour, to a heat at which nickel would melt. The result was a brown 

 unfused mass, which, under a magnifying power of 300 diameters, 

 presented, besides the particles of metallic iron throughout the whole 

 mass, a net-work of copper-colored, strongly metallic, shining, short 

 prisms, which, as indicated by the color, are composed of the same 

 5ubstance before examined. The titanium used in all these experi- 

 ments was produced in a furnace in the Hartz, where lately a mass 

 of titanium has been found, estimated at 80 Ibs. (Hanover) weight. 

 Prof. Wohler has also ascertained, that the crystals obtained by Rose 

 from the double chloride of titanium and ammonia, by subjecting the 

 same to the action of heat in gaseous ammonia, are not pure metallic 

 titanium, as was supposed, but a nitride of titanium, containing nearly 

 28 per cent, of nitrogen. But this is not the only isolated compound 

 of nitrogen and titanium, two other compounds having been found to 

 exist. All these compounds possess the remarkable property, if 

 mixed with oxides of lead, copper, or mercury, and heated, of emitting 

 a lively, sparkling flame and reducing the oxides of these metals. All 

 of these compounds, moreover, can sustain a temperature at least equal 

 to that at which silver would melt, without undergoing decomposition. 

 In conclusion, Prof. Wohler answers the question, What is the 

 character of pure titanium ? This substance was first observed by 

 Berzelius ; it was not, however, closely examined by him. It is that 

 body which is produced by heating the double fluoride of potassium 

 and titanium with potassium. After washing and separation by 

 water, pure titanium remains behind, as a dark, green, uncrystalline, 

 and tolerably heavy powder. Even after being subjected to pressure, 

 one cannot discern a shade of color approaching that of copper, and 

 under the microscope it appears as a cemented mass, having the color 

 and lustre of iron. If heated in contact with the air, it burns with 

 much splendor ; sprinkled into a flame, it burns at a considerable 

 distance above its point, with a splendor resembling a discharge of 

 the electric fluid. Its comportment in chlorine gas is very similar, 

 requiring also, however, the aid of heat ; mixed with minium and 

 heated, it burns with such an intense evolution of caloric, that the 

 mass is thrown out with a report. Titanium possesses the property 

 of decomposing v/ater ; at a temperature of 212 F., in pure water, 

 hydrogen gas begins to be evolved, and in warm hydrochloric acid it 

 is dissolved with a brisk disengagement of hydrogen. Ammonia 

 throws dowii from the solution a black oxide ; if the liquid be then 



