3o6 



NA TURE 



[January 28, 1892 



at ordinary room temperature, must be allowed to issue in a 

 stronger current from the containing bomb to obtain this cloudy 

 look. If a brass spiral is attached to the mouth of the bomb, 

 the cloud-formation is made very difficult ; and if the spiral is 

 then strongly cooled, the cloud reappears. With the spiral in 

 boiling water, no cloud is formed, however free the stream of 

 gas. This behaviour quite corresponded to the electrical effects. 

 Even a weak stream of gas from the vessel of liquid carbonic 

 acid gave a well-marked charge ; a less effect was had with the 

 bomb of compressed gas ; still less when the spiral was added ; 

 and least of all with the spiral in hot water, however violent the 

 stream of gas. Prof. Wesendonck concludes that gaseous car- 

 bonic acid is not capable of generating electricity by mechanic al 

 friction on metal. 



Herr Angstrom has been lately engaged in examining with a 

 bolometer the heat radiation of various rarefied gase? under 

 the electric discharge. He confined himself to the stronger 

 positive light, using cylindrical glass tubes, with lateral 

 electrodes, and rock salt plates at the ends. An accumulator of 

 800 Plante elements was the source of electricity. Briefly 

 stated, the results are these :— With a given pressure the radia- 

 tion is proportional to the intensity of the current. With con- 

 stant current, the radiation does not vary while the pressure 

 varies between O'l and i'5 mm., but at higher pressures it 

 increases somewhat. With the same gas and pressure, the 

 composition of the radiation is constant, and does not depend 

 on the intensity of the current. With varying density of gas, 

 the ratio of the intensity of radiation of shorter wave-lengths 

 to that of the whole decreases with increase of pressure. (This 

 ratio varied, ^^., from 46 to 15 percent, in carbonic oxide between 

 the above pressure limits.) Thus this ratio, at low pressures, 

 reaches much higher values than in our ordinary light sources. 

 The intensity of total radiation varies considerably in different 

 gases, and stands in no simple relation to the molecular weight, 

 nor to difference of potential in the gas ; nor does it seem to 

 depend on absorption of gas at ordinary pressure and temperature. 



Dr. Symes Thompson will deliver Gresham Lectures, on the 

 nerves, on February 2, 3, 4, and 5. They will begin each 

 evening at six o'clock, and will be free to the public. 



Prof. H. G. Seeley, F.R. S., will deliver a course of four 

 lectures at Gresham College, in connection with the London 

 Geological Field Class on the four Saturday afternoons in 

 February. The subject will be: " The Physical Geography of 

 the London District in relation to its Geological Structure." 

 Particulars may be had of the Hon. Sec, Mr. J. Herbert Hodd, 

 78 Queen's Road, Finsbury Park. 



The third series of lectures given by the Sunday Lecture 

 Society begins on Sunday afternoon, January 31, in St. George's 

 Hall, Langham Place, at 4 p.m., when a lecture will be 

 delivered by Mr. Sergius Stepniak. Lectures will subsequently 

 be given by Dr. Andrew Wilson, Mr. George Wotherspoon, 

 Mrs. Proctor (widow of the late Richard A. Proctor), Mr. 

 Frank Kerslake, Miss Amelia B. Edwards, and Dr. E. E. 

 Klein, F.R.S. 



The following gentlemen have arranged to give lectures at 

 the Royal Victoria Hall during February : on the 2nd, Dr. 

 James Edmunds on "An Emigrant in North- West Canada" ; 

 9th, Prof. Oliver on "The Habits of Plants"; i6th, Prof. 

 Carlton Lambert on "Gas, Parafifine, and Electricity" (with 

 experiments) ; 23rd, Mr. J. W. Gregory on " Waterfalls." 



At the last meeting of the Chemical Society, on January 21, 

 Prof. Smithells gave a preliminary account of some novel ex- 

 periments on "The Origin of Flame Coloration." At a previous 

 meeting he described a method of widely separating the two 

 cones of combustion which constitute the flame of a bunsen 

 burner (see Nature, vol. xlv. p. 214). Trying the effect of intro- 



NO. I 161, VOL. 45] 



ducing metallic salts into the two cones separately, he has 

 found that in most cases no marked differences of coloration are 

 produced. But in the case of copper salts the inner cone 

 assumes merely a general yellowish luminosity, whilst the outer 

 cone is brilliantly tinged with the green colour commonly 

 ascribed to the vapour of copper or copper salts. Of the two 

 cones the inner one is by far the hotter. The chief difference 

 between them, apart from this, is that the inner one is sur- 

 rounded by an atmosphere containing carbon dioxide, carbon 

 monoxide, water, and hydrogen, but no uncombined oxygen^ 

 whereas the outer one is bounded by atmospheric air. The only 

 explanation of the phenomenon that has yet offered itself is that 

 the production of the green colour is connected with the act of 

 oxidation. Further support is lent to this view by the fact that 

 if copper oxide dust be introduced into the inner cone, a general 

 luminosity devoid of green is produced, but at the same time 

 the outer cone is coloured green. It would appear as if the 

 copper oxide were reduced to metal in the inner cone, and 

 simply glowed as a solid body, the copper being thereupon re- 

 oxidized in the upper flames in contact with the air. The hypo- 

 thesis is therefore tentatively put forward that some flame 

 colorations at any rate are due to ether disturbances accom- 

 panying the act of chemical combination, and are not to be 

 ascribed to the mere incandescence of single substances. 

 Further experiments made with the apparatus are conformable 

 to this view, but Prof. Smithells has commenced a spectroscopic 

 study of the subject, and has in view the prosecution of inde- 

 pendent methods of inquiry. Understanding that the flame- 

 dividing apparatus is likely to come into general use, he has becD 

 led to give this preliminary account of the experiments. 



A new liquid compound of carbon, oxygen, and chlorine was 

 described by M. Troost on behalf of M. Fauconnier at the last 

 meeting of the Academic des Sciences. It may be considered 



COCl 

 as oxalyl chloride, | , the dichlorine derivative of oxalic 



COCl 

 acid, and has been prepared by M. Fauconnier by the action of 

 phosphorus pentachloride upon ethyl oxalate. Prof, von Richter 

 has previously shown that when these two substances are 

 allowed to react upon each other, a compound of the composi- 



COCl 

 tion I is formed. This substance, which has been 



COOC2H5 

 termed chloroxalic ether, is a fuming liquid possessing a pungent 

 odour, and boiling at I3i°'5. The new compound is produced 

 by varying the conditions of Prof Richter's experiment in the 

 following manner. A mixture of phosphorus pentachloride and 

 ethyl oxalate, in the proportion of two molecules of the former to 

 one of the latter, is heated by means of an oil -bath in a flask 

 fitted with a Le Bel-Henninger fractional distillation appa- 

 ratus and condenser. When the temperature of the bath reaches 

 125°, a lively reaction commences, accompanied by evolution of 

 ethyl chloride vapour and hydrochloric acid. When the tem- 

 perature is slowly raised to 150°- 155°, a liquid mixture distils 

 over, consisting of oxalyl dichloride, phosphorus oxychloride, and 

 ethyl chloride. When this mixture is subjected to repeated 

 fractional distillation, the oxalyl dichloride is eventually isolated 

 as a mobile, strongly-fuming liquid boiling at 70°. It is 

 endowed with an odour more irritating even than those of the 

 chlorides and oxychloride of phosphorus, and which reminds 

 one somewhat of carbonyl chloride, COClg. It reacts violently 

 with water, forming oxalic and hydrochloric acids. With an- 

 hydrous alcohols it reacts in an extremely energetic manner. 

 Thus with methyl alcohol it forms methyl oxalate, which may 

 be obtained crystallized from the solution, and hydrochloric acid 

 is evolved, great rise of temperature being manifested during the 

 reaction. The formation of this second oxychloride of carbon is 

 of considerable interest, as emphasizing once more the disap- 



