476 Intelligence and Miscellaneous Articles. 



From which its formula appears to be H-' C^ ; but according to the 

 density of its vapour which is equal to 4*18 it may be represented 

 by H3« C^-K 



There are therefore in the oil in question two carburets of hydro- 

 gen, on adding which together the carburetted hydrogen from which 

 they are derived is reproduced.— Z'/ws^iYw^, 30th Aug. 1838. 



COMBINATION OF AZOTE WITH METALS. 



The experiments of Thenard and Despretz seem to have proved 

 that certain metals absorb azote at a high temperature ; it is, how- 

 ever, observed by M. Pfaff, that Berzelius has remarked that the 

 experiments of Despretz are incomplete : and PfafF states that it 

 appeared to him that a diffei'ent mode from that followed by Des- 

 pretz might be adopted, to prove the absorption of azote by certain 

 metals at a red heat. It is well known that ammoniacal gas when 

 resolved into its elements, is converted into a mixture of three 

 volumes of hydrogen and one volume of azote. In the decomposition 

 of ammoniacal gas, as effected during its passage over red-hot metals, 

 the same relation ought to exist between the volumes of hydrogen 

 and azote, if the azote is not absorbed by them; and if the remark- 

 able alteration which their properties undergo does not depend on 

 the absorption of this gas, there ought, on the other case, to be an 

 increase in the proportion of the azote. In order to perform these 

 experiments, M. PfaiF selected good porcelain tubes, in which was 

 placed a copper wire, two lines in diameter, and of considerable 

 length. The ammoniacal gas was disengaged from sal ammoniac by 

 lime, and conducted over caustic potash, exposed to a strong red 

 heat ; the other end of the porcelain tube was made to communicate, 

 by a tube bent at a right angle, with a Woulf 's bottle containing 

 water to absorb the undecomposed ammoniacal gas. The experiment 

 was continued several hours, to decompose a great quantity of ammo- 

 niacal gas. The gas was received in separate portions ; at the close 

 of the experiment the copper wire exhibited beautiful iridescence, 

 and those parts of it which had suffered most change were extremely 

 friable. The gas disengaged was examined in a Volta's eudiometer. 



The following were the results of the examinations of the portions 

 of gas, in the order in which they were received : 



First portion. — 400 volumes were detonated with 200 volumes of 

 oxygen gas ; the residue was 200 volumes, consequently 400 volumes 

 had disappeared, of which 266f were hydrogen; so that the 400 

 volumes of the gas analysed contained only 266|- of hydrogen gas. 

 PVom the following experiments it may be concluded that this first por- 

 tion was mixed with a portion of the atmospheric air of the vessels. 



Second portion. — 300 volumes of this gas were detonated with oOO 

 volumes of oxygen gas ; the residue was 213, there had consequently 

 disappeared 387, of which 258 were hydrogen. These 300 volumes 

 of gas decomposed, if they were composed of hydrogen and azote in 

 the proportion of 3 : 1, ought to contain only 225 volumes of hydro- 

 gen and 75 of azote; there was, therefore, an excess of 33 in 300, and 

 the azote amounted to only about one -seventh, instead of one-fourth. 



Third portion. -^300 volumes were detonated with 300 of oxygen 



