90 



CHEMISTKY. 



der passes through capillary metallic tubes to 

 manometers (to show the pressure) and to a 

 reservoir of mercury a, which is forced up into 

 the glass tube m. This glass tube, which holds 

 the gas to be liquefied, is surrounded by an- 

 other containing a freezing mixture, and the 

 whole is covered by a glass shade, on the floor 

 of which is placed some substance which has 

 strong affinity for moisture, and which prevents 

 the deposit of vapor on the outside of the tube, 

 hindering observation. The high pressure of 

 the water forces the mercury up into the tube, 

 thus compressing the gas. " If now," says M. 

 Cailletet, " we inclose oxygen or pure carbonic 

 oxide in the compression-apparatus; if we re- 

 duce these gases to a temperature of 29 Cent, 

 by the aid of sulphurous acid at a pressure of 

 about 300 atmospheres, both gases still retain 

 their gaseous state. But if they be released 

 suddenly [by reversing the small wheel 0], so, 

 according to Poisson's formula, producing a 

 temperature of at least 200 below the start- 

 ing-point, we at once see a heavy mist, caused 

 by the liquefaction, or even, perhaps, the solidi- 

 fication, of the oxygen or carbonic oxide. The 

 same phenomenon is observed in releasing car- 

 bonic acid and protoxide and bioxide of nitro- 

 gen, which have been subjected to strong 

 pressure." 



After having obtained these results, at a ses- 

 sion of the Academy on December 31st, M. 

 Cailletet announced that he had won a com- 

 plete victory over the other permanent gases. 

 M. Dumas informed the members present at 

 the session that the able experimenter had suc- 

 ceeded in liquefying nitrogen, atmospheric air, 

 even hydrogen itself, which would seem to 

 have been the most refractory gas of them all. 



The New Metals Davyum and Neptunium. 

 M. Sergius Kern, of St. Petersburg, discovered, 

 toward the middle of the year 1877, a new 

 metal belonging to the platinum group, to 

 which he gave the name of Davyum, in honor 

 of Sir Humphry Davy. Dissolved in aqna 

 regia, and treated with potassa, davyutn yields 

 a yellow precipitate, hydrate of davyum. 

 Chloride of davyum, dissolved in a solution of 

 potassic cyanide, yields, in crystals, a double 

 cyanide of davyum and potassium. A concen- 

 trated solution of davyum chloride, with po- 

 tassic sulphocyanide, gives a red precipitate, 

 which, on being slowly cooled, yields large red 

 crystals; if this precipitate be calcined, the 

 sulphocyanureted davyum assumes the form 

 of black powder. Davyum chloride forms 

 double salts with chlorides of potassium and 

 ammonium ; these are insoluble in water, but 

 highly soluble in absolute alcohol. The double 

 salt of sodium and davyum is nearly insoluble 

 in water and alcohol. Three experiments made 

 to determine the density of davyum yielded, at 

 temperature 24 Cent., these results, namely: 

 9.383, 9.38T, 9.392. The author is of the opin- 

 ion that the atomic weight of davyum is over 

 100 probably about 150 to 154. 



Another new metal, discovered during the 



past year, is Neptunium, found by Hermann in 

 a mineral coming from Haddam, Conn. The 

 history of this discovery is briefly stated as 

 follows in the American Journal of Science, 

 which publishes a synopsis of a communication 

 from the discoverer to a German scientific 

 journal. The mineral worked on was labeled 

 "tantalite," but, on examination, it proved to 

 be columbite and ferroilmenite in equal parts. 

 The metallic oxides separated from the mineral 

 consisted of Ta 2 O 6 32.39, Cb 4 O 7 36.79, IhOi 

 24.52, Np 4 O 7 6.30. To obtain the neptunium, 

 the pulverized mineral was fused with hydro- 

 potassium sulphate, the acid hydrates digested 

 with ammonium sulphide and hydrochloric 

 acid, washed well with water, dissolved in hy- 

 drofluoric acid, mixed with an equivalent quan- 

 tity of potassium fluoride, and the solution 

 diluted to 40 parts boiling water to one of 

 fluoride. On cooling, tantalum -potassium flu- 

 oride crystallized in delicate prisms. On evap- 

 oration, columbium-potassium fluoride and 

 ilmenium -potassium fluoride crystallized out, 

 leaving an acid mother-liquid. This was di- 

 luted with 20 parts water, heated to boiling, 

 and sodium hydrate added in excess. An 

 amorphous precipitate of sodium neptunate 

 was formed, mixed with minute crystals of 

 columbate. The precipitate was collected on 

 a filter, pressed out, and boiled with 25 parts 

 of water. The columbate dissolved, the nep- 

 tunate remained. The latter was fused with 

 hydro- potassium sulphate, the fusion was treat- 

 ed with boiling water, and the undissolved 

 residue of neptunic acid washed and dried over 

 sulphuric acid. Neptunic acid resembles in 

 general the other acids of the group, but is dis- 

 tinguished from columbic and ilmenic acids by 

 the insolubility of the sodium double fluoride, 

 and from tantalic acid by the ready solubility 

 of its potassium double fluoride. Neptnnic 

 acid gives with phosphorus salt in the inner 

 blow-pipe flame a wine-yellow bead, the sodium 

 salt a gold-yellow glass ; while tantalic acid 

 gives no color, columbic acid gives blue, and 

 ilmenic acid gives brown. "With tincture of 

 galls, the sodium salts give, on addition of hy- 

 drochloric acid, a sulphur-yellow precipitate 

 with tantalic, orange with columbic, brick-red 

 with ilmenic, and cinnamon-brown with nep- 

 tunic acid. Boiled with tin and hydrochloric 

 acid, neptunic acid gives, like columbic and 

 ilmenic acids, a blue solution. From the pure 

 crystallized double potassium fluoride, the 

 atomic weight of neptunium was fixed as 118, 

 its atomic volume as 18, and its specific grav- 

 ity as 6.55. The formula of the acid is NpO T , 

 (H a O) ls . The sodium salt crystallizes in prisms. 

 The author prepared metallic columbium and 

 ilmenium in the pure form, and determined the 

 amount of oxygen taken up by these metals on 

 heating them in the air. Columbium required 

 20.49 and ilmenium 37. 96 of oxygen; the amount 

 obtained by Rose being 20.60, and by Marignac 

 38.00. Rose, therefore, it is clear, had pure 

 columbium ; while it is equally clear, according 



