CHEMICAL SCIENCE. 283 



Another process was tried ; it was that which lately has so well succeeded 

 with Wohlcr and Deville ; its principle is to act upon chloride of tungsten 

 bv means of the metal sodium. 



m 



The first experiments were made with the red matter, known under the 

 name of chloride of tungsten ; its vapor was passed over the sodium, heated 

 in a glass tube filled with hydrogen ; the reaction took place, and a brilliant 

 metallic matter deposited itself on the tube, but in very small quantity, 

 whilst a large quantity of water was disengaged, although every precaution 

 had been taken to dry the hydrogen ; this led to the belief that the supposed 

 "chloride was an oxichloride, and a true chloride was prepared and passed 

 over the sodium as before, when only small quantities of a substance in 

 brilliant plates coated the tube, but there was formed an abundant brown 

 powder, which was purified by washing. This is pure tungsten, but Avith- 

 out the lustre of the metal reduced by hydrogen from tungstic acid. 



"According to some experimenters, the atomic weight of tungsten has 

 been represented by ninety-six, and by others at ninety-two, but there is 

 every reason to believe that this last number is even too high, because it is 

 obtained by operating upon tungstic acid prepared by means of carbonate 

 of soda, which invariably retains traces of the alkali ; besides, the tubes in 

 which the reductions were effected were not heated high enough. In this 

 case the tungstic acid was prepared by acting on the mineral wolfram at 

 once with nitro-hydrochloric acid, and supersaturating the acid solution 

 with ammonia, which gives a tungstate perfectly crystallized. After a 

 second crystallization the salt is calcined, and leaves the tungstic acid fit 

 for the experiment. Five results were obtained, and the tungstic acid 

 considered of the formula Ts O 3 gave the atomic weight of tungsten as 

 eighty-seven. These experiments were confirmed by operating upon tung- 

 stic acid prepared in a different manner. 



Tungsten obtained by the action of tungstic acid or hydrogen is in small 

 very sharp crystalline grains, isolated from one another, brilliant, suscepti- 

 ble of taking a beautiful polish when rubbed, and scratching glass with 

 facility ; placed in the fire of a forge so powerful as to alter the shape 

 of the crucible, they do not melt. A very powerful Bunsen's battery was 

 required to melt tungsten, a very notable portion of the metal became oxi- 

 dated and burned with a bluish green flame resembling zinc under similar 

 circumstances. It melts similarly and very quickly in a jet of oxygen 

 and hydrogen ; but still the greater portion of the metal oxidates and dis- 

 appears in fumes of tungstic acid. The density of this melted metal is 

 17 -2. Experiments were made to manufacture it in a similar manner to 

 platinum ; but even the most skilled workers in platinum failed in attempt- 

 ing it. Oxygen, dry or moist, at the ordinary temperature, does not affect 

 it, even after being in contact with it eight months ; but at a temperature of 

 redness it bums and yields tungstic acid free from the lower oxides ; in air 

 the heat ought to be stronger, but the result is the same. Sulphur in a 

 state of fusion does not exert a rapid action upon it. At ordinary tem- 

 peratures it does not burn in dry chlorine gas, but at 250 to 300 degress 

 Fah., if air and moisture are carefully excluded from the apparatus, it 

 forms chloride of tungsten Ts C 13 . 



