402 



NATURE 



[August 25, 1892 



carbon Flame.', " described the results of the analyses of the 

 gases drawn from an ordinary coal gas flame at different heights. 

 He had found that the heavy hydrocarbons which occur in the 

 non- luminous part of the flame are almost entirely converted 

 into acetylene before they reach the luminous zone. The 

 luminosity of the flame is, in his opinion, brought about by 

 dissociation of the acetylene, the temperature required for this 

 dissociation varing with the degree of dilution of the acetylene. 

 Under the circumstances already described, where the amount 

 of acetylene present was l"i to 13 per cent., the temperature 

 was 1200°, whilst in the flame of a paraffin lamp, where about 

 double the amount of acetylene was present, the temperature 

 was found to be 1000°. 



On passing ethylene through a heated tube at different tem- 

 peratures he found that at goo° the chief products were methane 

 and acetylene ; at 1000° there was still no hydrogen and no 

 carbon, but more oil and heavy hydrocarbons, whilst at a still 

 higher temperature hydrogen and carbon appeared amongst the 

 products ; above 1200° there was much carbon and little or no 

 hydrocarbons. The actual temperature of the gas flame used 

 was 500° at a distance of half an inch above the burner ; 1279° 

 at the top of the non-luminous zone, and 1370° at the top of the 

 luminous zone. 



Prof. Smithells followed with a number of very beautiful 

 " Experiments on Flame." He held that the ordinary candle 

 flame showed four and not three zones as usually described. He 

 considered that the phenomena of combustion in flames ought 

 to be studied by using gases of simple and definite com- 

 position rather than a variable and complex mixture such as 

 coal gas. 



He showed, by means of experiments, the two distinct zones 

 in the non-luminous Bunsen flame, and how these could be 

 separated, and their character varied according to the amount of 

 air admitted, and similar illustrations were given by burning a 

 jet of air laden with benzene vapour. Under the conditions of 

 the Bunsen flame he had found that whatever hydrocarbon was 

 used the products withdrawn from the inner cone consisted of 

 carbon monoxide, carbon dioxide, hydrogen, and water vapour, 

 whilst in the case of the benzene flame described, when the air 

 supply was so regulated as to produce a luminous zone between 

 the inner and outer zoneF, acetylene was found amongst the 

 gases withdrawn from that zone. 



His experiments had led him to conclude that when the 

 hydrocarbon is starved of oxygen the carbon burns preferentially 

 to the hydrogen. 



Prof. Smithells then introduced a spray of cupric chloride 

 solution into the gas, and showed that the inner flame remained 

 unaltered in appearance, whilst the outer flame became green. 



He is of opinion that the decomposition of the salt takes place 

 in the inner flame, and that the colouration of the outer flame is 

 due to the projection of the products of decomposition through 

 the outer flame. A discussion followed these papers, in which 

 Sir G. G. Stokes described the experiments he had performed 

 with a view to determine whether the luminosity of the flame 

 was due to carbon or to hydrocarbons. He was not in favour 

 of the idea that the colouration of the flame was due to chemical 

 reactions taking place within it. Sir Henry Roscoe thought it 

 due to the separation of metal in the flame, and not to the oxide. 

 Prof. Liveing quoted the results of his observations on the 

 spectrum of oxygen, and expressed his adherence to the hydro- 

 carbon theory of luminosity. Prof. Ramsay supported Prof. 

 Smithells' contention. The discussion came to a conclusion 

 with the replies of the authors of the papers. 



Dr. J. A. Harker then followed with a description of " The 

 Reaction of Hydrogen with Mixtures of Hydrogen and Chlorine. " 

 He finds that as had been previously observed by Horstmann, 

 Bunsen, and others, the hydrogen combines partly with the 

 oxygen and partly with the chlorine, but that the reaction 

 varies with the quantities of the constituent gases present, 

 and lakes place in accordance with the law of Guldberg and 

 Waage. 



Prof. Clowes gave the results of the investigations which he 

 had taken up in order to produce a safety lamp which should 

 indicate with greater accuracy the presence of inflammable 

 gases and vapours in air. In confirmation of previous observa- 

 tions he had found hydrogen to be by far the most sensitive 

 flame, and he described a means by which hydrogen could be 

 burnt in an ordinary oil safety lamp with greater convenience 

 than had hitherto been possible. 



A discussion which was to have been held in conjunction 



NO. II9T, VOL. 46] 



with Section D on the "Chemical Aspects of Bacteriology," 

 fell through. 



Prof. Roberts Austen gave a paper on the " Effect of Small 

 Quantities of Foreign Matter on the Properties of Metals." The 

 addition of two-tenths per cent, of lead or bismuth to gold was 

 found to render it quite brittle, whilst extremely small quantities 

 of phosphorus, magnesium, and zinc made nickel malleable. 

 Such phenomena had no doubt been of great interest in ancient 

 times to ihe alchemist, but to-day they constituted all-important 

 questions for the engineer. Experimenting on gold, which could be 

 obtained more readily than most other metals free from impuri- 

 ties, either solid or gaseous, he found that the tenacity was 

 decreased by the addition of small quantities of elements whose 

 atomic volumes were greater than that of gold, whilst those 

 elements whose atomic volume was the same or smaller than 

 that of gold, increased its tenacity. Lithium and aluminium 

 acted in an exceptional manner. Furthermore, whilst the 

 addition of 10 per cent, of aluminium gave an alloy melting at 

 400° lower than gold, 23 per cent, of the admixture yielded a 

 brilliant alloy having a higher melting point than gold. He 

 pointed out also that gold during the process of cooling showed 

 abnormalities similar to those shown by iron, which, however, 

 disappeared when the operation was carried out under pressure. 

 Prof. Hartley had found that iron required to be slightly 

 oxidised before it could be melted, even at a temperature which 

 sufficed to melt platinum. He had always found that silver and 

 copper, unless prepared with special precautions which he 

 described, contained gold. 



Dr. Gladstone submitted a communication on the "Molecular 

 Refraction and Dispersion of Metallic Carbonyls and of Indium, 

 Gallium and Sulphur." The observations made on a sample of 

 the iron pentacarbonyl supplied to him by Mond indicated an 

 extreme dispersion for iron, even taking the highest value for 

 carbonyl previously recorded. Pie attributed, however, a still 

 higher value (ll'2) to carbonyl, and assigned a chemical formula 

 inaccordance therewith. With regard to sulphur he had found 

 that the values obtained varied only slightly, whether the sulphur 

 was in the liquid, solid or gaseous condition. Prof. Liveing 

 found that the same thing held for oxygen and nitrous oxide in 

 the liquid and gaseous conditions, and considered that this pointed 

 to the continuity of the gaseous and liquid states. 



Dr. G. H. Bailey gave a paper on " Impurities of Town Air." 

 He pointed out that the amount of air taken into the system 

 daily greatly exceeded that of the liquid and solid food, whilst \ 

 according to Tyndall expired air was very free indeed from solid i 

 particles, and that air was undoubtedly the medium by which ^ 

 many diseases were propagated, and that in towns, as a matter 

 of fact, the death-rate rose to very abnormal proportions during 

 those periods when the air was most polluted. Under these 

 circumstances it was a matter of surprise that so little attention 

 had been devoted in recent years to the determination of the 

 impurities in air. A very large amount of information had, it 

 was true, been obtained relating to the carbonic acid in air, and 

 this had led to valuable results ; but with the exception of Dr. 

 Russell's extremely interesting reports, hardly anything had been 

 done in the direction of determining the sulphurous acid and 

 organic matter with which town air, especially at certain seasons, 

 was laden. He then described the methods which had been 

 adopted by the Air Analysis Committee of Manchester for deter- 

 mining these impurities, showing how it was not only possible 

 to arrive at a measure of the amount of suspended organic matter, 

 but also to ascertain proximately how far it was of a noxious 

 character. Such analyses may appropriately be supplemented 

 by a bacteriological examination of air. Some hundreds of 

 analyses of the air of London, Manchester, and Liverpool had 

 been made, and the following conclusions were drawn from 

 them : — (i) That in clear breezy weather the amount of sul- 

 phurous acid in town air does not exceed one milliogramme per 

 100 cubic feet of air. (2) That in antiyclonic periods, and 

 especially in times of fog, diffusion is seriously interfered with, 

 and the quantity has been found as high as 50 milligrammes. 

 (3) That the organic impurities in air also increase under similar 

 conditions to those which promote the accumulation of sulphurous 

 acid to 40 or 50 times their normal amount at least. 



In the discussion which followed Sir Douglas Gallon ex- 

 pressed himself well satisfied with the enquiry, and hoped that 

 the work would be continued. He called attention to the ten- 

 dency for decaying matter to collect, especially in certain areas of 

 large towns and the danger of allowing such accumulations. Mr. 

 A. E. Fletcher, Chief Inspector of Alkali Works thought the 



