544 



NA TURE 



[April 4, 1S95 



Examioation with high powers showed, however, that the line 

 remained rigorously single when the sodium lines would be 

 widely separated. On throwing sodium light int > the spectro- 

 scope simultaneously with that from the new gas, the spectrum 

 of the latter was seen to consist almost entirely of a bright 

 yellow line, a little to the more refiangible side of the sodium 

 lines, and separated from them by a space a little wider than 

 twice that separating the two sodium components from one 

 another. It appeared as bright and as sharp as D, and Do. 

 Careful measurements gave its wave-length 5S7 '45 ; the wive- 

 lengths of the sodium lines being D, 589'5i, and DjSSS'gi. 

 The differences are therefore — 



D, 



D.. 



\Va\"e-length>;. 



589-51 



DiiTerences. 



o'6o 



I '46 



588-91 



New line 587-45 



The spectrum of the gas is, therefore, that of the hypothetical 

 element Helium, or Dj, the wave-length of which is given by 

 Angstnim as 5S7-49, and by Cornu as 587-46. 



Besides the Helium line, traces of the more prominent lines of 

 argon were seen. 



Comparing the visible spectrum of the new gas with the band 

 and line spectrum of nitrogen, they are almost identical at the 

 red and blue end, but there is a broad space in the green where 

 they differ entirely. The Helium tube shows lines in the follow- 

 ing positions : — 



Wave-length. 



(a) D3, yellow 5S7-45 Very strong. Sharp. 



(b) Yellowish green ... 568-05 Faint. Sharp. 



(0 Yellowish green ... 566-41 Very faint. Sharp. 



(d) Green 516-12 Faint. Sharp. 



(^) Greenish blue ... 50081 Faint. Sharp. 



(/) Blue 480-63 Faint. Sharp. 



I have taken photographs of the spectrum given by the Helium 

 tube. At first glance the ultra-violet part of the spectrum looks 

 like the band spectrum of nitrogen, but closer examination 

 shows considerable differences. Some of the lines and bands 

 in the nitrogen spectrum are absent in that from the Helium 

 tube, whilst there are many fmc lines in the latter which are 

 absent in nitrogen. Accurate measurements of these lines are 

 being taken. 



ISOLATION OF FREE HYDRAZINE, N^Hy 



VT LOBRY DE BRUYN contributes a memoir of special 

 interest to the current issue of the iPc-i-H-'iV das Travaux 

 Chimiques des Pays-Bos. It is not long since the distinguished 

 Amsterdam chemist succeeded in preparing for the first time 

 free anhydrous hydroxylamine, and now he announces that he 

 has likewise been successful in isolating free hydrazine by a 

 similar method. Eight years ago the important discovery of 

 hydrazine »-as made by Prof. Curtius, and since that time the 

 amount of knowledge which has been accumulated concerning 

 the base and its compounds by Prof. Curtius and his assistants 

 is so large that a separate volume might well be devoted to it. 

 Nevertheless, the free anhydrous base itself has not hitherto 

 been satisfactorily prepared ; indeed it would now appear, in 

 the light of M. dc liruyn's remarkable work, ihit it has not 

 hitherto been in any way isolated. The h) Irate of the base has 

 been obtained in the pure state and fully described by Prof. 

 Curtius, hut in his later communications he has expressed the 

 view that the free base is so uns'.ahle that most probably it is 

 incai>able of separate existence. The hydrate only is produced 

 when the salts arc decomposed by a caustic alkali, and even 

 iligestion in a Bcilcd tube at 170 with anhydrous baryta, h.as 

 failed to detach the water molecule from its combination with 

 hydrazine. It appeared, however, to M. de Bruyn that the 

 nature of the salts and other compounds of hydrazine rendered 

 it scarcely probable that the base was less stable than hydroxy- 

 lamine, and he considered it not unreasonable to hop: that it 

 might therefore be isolated in an an,alogous manner to the latter 

 laic, namely, by reacting upon the chl iride with solium 

 methylate in methyl alcohol solution. The experiments made 

 in this direction are only preliminary, but their result is so 

 interesting that an account of them i; at once published. 



The salt employed was the chloride N.Hj.HCI, prepared as 

 described by Prof. Curtius. Ten grams of this salt in powder 

 were added to 200 c.c. of pure methyl alcohol, and a solution 

 of the calculated quantity of sodium methylate CHjONa in 

 methyl alcohol were subsequently added. Common salt was 

 immediately precipitated without any perceptible rise of tem- 

 perature. The mixture was consequently boiled for half an 

 hour in a flask fitted with an upright condenser. After cooling 

 the sodium chloride was removed by filtration, and the solution 

 submitted to distillation. At first mainly methyl .alcohol p.assed 

 over, but after a time the distillate began to contain augmenting 

 quantities of hydrazine ; the pressure was then reduced, and four 

 further quantities separately collected. The temperature of 

 ebullition rose to 55°, although the pressure was materially re- 

 duced. The last 20 c.c. contained the greater portion of the 

 base. This last fraction was then again distilled at the ordinary 

 pressure, until a residue was left which contained 73 per cent, 

 of hydrazine. The hydrate of hydr.azine only contains 64 per 

 cent, of the base, hence it was evident that some free hydrazine 

 had been obtained, and that hydrazine is a comparatively stable 

 substance boiling at a temperature higher than that of methyl 

 alcohol. 



In a second experiment 42 grams of chloride of hydrazine 

 were treated in a similar manner with methyl alcohol .and 

 sodium methylate. This larger quantity evinced some rise of 

 temperature after the admixture, and the heat caused by the 

 re.action of the hydrazine chloride, which at first had not all 

 dissolved, «-as just sufficient to keep the liquid boiling for several 

 minutes, when once it had been brought to the boiling point by 

 extraneous heating. After the conclusion of the reaction 

 the contents were cooled, avoiding the access of moisture and 

 carbon dioxide, the sodium chloride filtered off as before, and 

 distillation proceeded with, at first in an ordinary distillation 

 apparatus and afterwards with the aid of a Le Bel-Henninger 

 apparatus. A residual 40 c.c. was again fractionated under 

 reduced pressure and six portions collected. The sixth friction 

 contained no less than 82 6 per cent, of N„Hj. A smaller 

 quantity passing over after removing the sixth fraction contained 

 over 84 per cent. The fifth and sixth portions solidified when 

 cooled by a freezing mixture of ice and salt. The crystals 

 mt Ited about 4°. Although the crystals when exposed to the 

 air exhaled dense white fumes, owing to the attraction of 

 moisture, a number of them were quickly pressed between 

 cooled blotting paper, weighed, and volumelrically analysed. 

 The analytical numbers corresponded to 92 per cent, of NjH^, 

 a result which, considering the extremely hygroscopic nature of 

 the crystals, would appear to indicate that they consisted of 

 practically pure N„Hj. The dried crystals melted at -1° 

 to -2°. 



A drop of the liquid obtained by fusion of the crystals did 

 not explode when heated with a naked flame ; a yellow flame 

 was produced, however, accomjianied by a hissing noise. The 

 liquid base is heavier than water and considerable heat is 

 evolved upon mixing it with a small quantity of the latter liquid. 

 Dry oxygen slowly oxidises it. When paper is moistened with 

 a drop of hydrazine and exposed to the air, it becomes hot 

 spontaneously and fumts strongly. Crystals of sulphur dissolve 

 promptly in the liquid base with considerable rise of tempera- 

 ture and formation of a reddish-brown liquid whose odour 

 reminds one of ammonium sulphide ; upon the addition of 

 water to this liquid, sulphur is precipitated. The halogens 

 react very violently with hydrazine, producing their acids, and 

 liberating nitrogen. Iodine disappears instantly, and a quanti- 

 tative experiment showed that the reaction proceeded in accord- 

 ance with the equ.alion NjIIj ••- 2[„ = N3 -f 4HI. Potassium 

 permanganate or bichromate act with great violence upon the 

 licjUid base, but the reaction is unaccompanied by either incand- 

 escence or explosion. The liquid appears to possess the further 

 property of readily dissolving many salts, such as the potassium 

 salts of (he halogen acids, and nitre. 



It would thus appear that, instead of being a gas, as at first 

 supposed by Prof. Curtius, free hydrazine is at the ordinary 

 tcmiicralure a liquid, which, however, solidifies at a tempera- 

 lure in the neighbourhood of that of the freezing-point of water, 

 to colourless crystals. The base is, moreover, endowed with ■ 

 very much higher degree of stability than was suppo.sed. M. 

 de liruyn is now engaged in preparing it upon a very much 

 larger scale, in order more completely to study its properiies. 



A. E. TUTTON. 



NO. 1327, VOL. 51] 



