210 



CHEMISTRY. 



he would also make potash and soda K 2 

 and Na a O. 



II. COMPOUNDS. Hydruret of Iron. "Wank- 

 lyn and Carius have studied the action of zin- 

 cethyl (C 4 H 5 Zn) upon the chlorides and iodides 

 of silver, copper, iron, and nickel. In case of 

 the iodide of iron, and probably of the chloride 

 of nickel, during the reactions hydrogen seems 

 to combine directly and simply with the metal. 

 "With iron, the product is a black powder, which 

 at ordinary temperatures and with exclusion of 

 water is preserved unchanged. Distilled water 

 being brought in contact with the compound, 

 pure hydrogen is given off, and protoxide of 

 iron remains. The composition of the hydru- 

 ret of iron is inferred to be Fe 2 H 2 , though it is 

 difficult to obtain it free from metallic iron. 



Peroxides of Potassium and Sodium. Har- 

 court has investigated the action of dry air and 

 oxygen on metallic potassium and sodium. By 

 carefully regulating the heat and the supply of 

 dry air, potassium may be wholly converted 

 into a white oxide, probably the binoxide. As 

 the oxidation increases, the color inclines to 

 yellow, and by employing finally pure oxygen, 

 a chrome yellow powder is obtained the per- 

 oxide its composition being regarded as K0<. 

 Thrown into water, this powder sets free pure 

 oxygen with effervescence, and the binoxide, 

 KOs, remains. The peroxide of sodium is pre- 

 pared by a similar process, and when not heat- 

 ed is of a pure white color. 



Silicuretted Hydrogen. Silicium belongs to 

 the same group of elements as carbon ; but the 

 analogue of C 2 H 4 (light carburetted hydrogen) 

 has only recently been found. Wdhler, in cer- 

 tain decompositions with the galvanic current, 

 observed bubbles of a spontaneously inflamma- 

 ble gas to arise at the aluminium electro-nega- 

 tive pole. The aluminium employed was found 

 impure with silicium ; and it was inferred that 

 the gas was silicide of hydrogen, SU H 4 . Very 

 recently, Dr. Martins succeeds in preparing this 

 gas in abundance. He mixes, in a wide-mouth- 

 ed bottle, 80 parts of chloride of magnesium, 

 20 of the chlorides of potassium and sodium 

 (taken in equivalent proportions), 40 of sodium, 

 and 70 of silico-fluoride of potassium, all dry, 

 the sodium in small pieces added last to the 

 mixture of the others, and the whole then well 

 agitated together ; and then suddenly projects 

 the mass into a tall Hessian crucible heated to 

 redness, covering this tightly. The mass fused, 

 the crucible is broken, and the slag removed. 

 This contains the required material for yielding 

 the gas a silicide of magnesium ; and being 

 broken up, is acted on under water with strong 

 hydrochloric acid. The gas can be collected 

 over water or mercury ; but allowed to escape 

 in bubbles into the air, it explodes into a white 

 flame, giving ascending rotating rings of smoke, 

 in the manner of phosphuretted hydrogen 

 (H P 3 ). It gives, however, no offensive odor, 

 and finally scatters in fine flakes of white dry 

 hydrated oxide of silica (Sis H 2 O s ). 



Hydrofluosilicic Acid. H. Deville prepares 



this acid by causing water to fall, drop by drop, 

 upon a mixture of fragments of stone ware and 

 of fluor spar, heated to redness in a tubulated 

 earthen retort ; or less conveniently, by passing 

 steam through such a mixture. Condensing 

 the vapors that arise, the liquid acid of about 

 17 (Beaume) is obtained ; and this may be 

 concentrated even to 29 (B.), its maximum 

 density, without deposit of silica a result with 

 the acid prepared in the ordinary way, quite 

 impracticable. At its maximum, the acid is 

 very energetic, expelling, when heated with 

 their compounds, almost all acids save the sul- 

 phuric. It has little action on stone-ware ves- 

 sels; rapidly destroys glass; but since it does 

 not attack organic matters, it can be kept in 

 wooden kegs. It is probably to become of con- 

 siderable industrial importance. (Annales de 

 Chim. et de Phys., Ixi, 333). 



Hyperchloric, Acid. Roscoehas investigated 

 the hydrates and principal salts of this acid, 

 which is obtained by decomposing chlorate of 

 potash with fluosilicic acid, distilling the chloric 

 acid, and purifying the distillate by means of 

 the hyperchlorates of silver and barium. Pure 

 concentrated solution of hyperchloric acid is a 

 colorless heavy oily liquid, strongly resembling 

 concentrated sulphuric acid. Distilled with 4 

 times its volume of concentrated sulphuric acid, 

 above 110 C. dense white vapors pass over ; at 

 200 C. oily drops succeed, condensing to a crys- 

 talline mass. The liquid is hyperchloric acid 

 (Cl O 6 H) ; the crystals, the hydrate discovered 

 by Serullas (C10 8 "H + 2 HO). The pure acid 

 is a colorless liquid, density 1.782, at 15 C. Its 

 vapor attracts water in the air, forming dense 

 white fumes ; dropped in water, the mixture is 

 strongly heated ; dropped on paper, wood, &c., 

 it explodes ; on charcoal, almost as violently as 

 tbe chloride of nitrogen. On the skin it pro- 

 duces a painful ulcer, healing only after some 

 months. Kept, even in the dark, it spontane- 

 ously decomposes, becoming darker, and finally 

 explodes. In the same paper, the author de- 

 scribes the hyperchlorates of ammonium and 

 some of the metals. (Ann. der Chem. und 

 Pharm,, cxxi, 346.) 



Combustion of Hydrocarbons in air at Ordi- 

 nary Temperatures. Karsten appears to have 

 proved, by experiments related in Poggendorff's 

 Annalen, vol. cix, p. 346, that organic sub- 

 stances containing carbon combine at ordinary 

 temperatures with the oxygen of the air, form- 

 ing carbonic acid and water; and he argues 

 that, since pure carbon is thus oxidized at com- 

 mon temperatures, as at higher, only more 

 slowly, the prevalent theory of the necessity 

 of a prior decay in some nitrogenous body, to 

 set up destructive change in the hydrocarbons, 

 is a mistake ; in other words, that the presence 

 of the nitrogenous substance is not essential. 

 Under water, if air have access to them, the 

 organic hydrocarbons (as woody fibre, starch, 

 &c.) are oxidized more rapidly than in the dry 

 state ; the access of air insufficient, they rot, 

 yielding carbonic acid and other gases yet im- 



