486 



NATURE 



[Septkmher 5, 1907 



rentage of carbon monoxide in the exhaust gases as the 

 petrol consumption was increased was shown very 

 strikingly by another curve, and it was apparent that if 

 the carburetter was set in the usual manner in order that 

 the engine might give its maximum power, no attention 

 being paid to petrol consumption, the exhaust was almost 

 certain to contain large quantities of carbon monoxide. 



The discussion on gaseous explosions was opened by 

 Mr. Dugald Clerk, who showed a part of the original 

 apparatus used by Bunsen in his classic experiments. Mr. 

 Dugald Clerk then briefly described his own important 

 work in this lield of research, beginning with his earlier 

 experiments, in which the pressures reached were re- 

 corded by means of a Richard's indicator, down to his 

 latest researches, some of which have been recently de- 

 scribed in papers read before the Royal .Society in March, 

 1906, and before the Institution of Civil Engineers at the 

 beginning of the present year, in which optical methods 

 have been used for obtaining records of the variation of 

 pressure with changes of volume and temperature in the 

 cylinder. Dr. Boudouard, of Paris, followed Mr. Dugald 

 Clerk, and described, with the help of blackboard 

 sketches, the apparatus which is being employed by the 

 committee which has been appointed by the French 

 riovcrnment to carry out a fresh series of experiments on 

 gaseous explosions, with the object of determining whether 

 the numerical results obtained in the earlier experiments 

 are trustworthy. Prof. Haber, of Carlsruhe, another well- 

 known worker in this subject, dealt very fully in his 

 remarks with the subject of the variation of the specific 

 heat of gases as the temperature of the gas is raised, and 

 Prof. Dixon and Prof. Hopkinson, who also spoke, took 

 up the same point. Prof. Dixon showed by a table of 

 results obtained in his own experiments that, at any rate 

 up to the limit of temperature to which he had at present 

 worked, the specific heat of CO, rose very markedly as 

 the temperature of the gas was increased, while, on the 

 other hand, there was very little apparent variation in 

 the specific heat of nitrogen. 



During the afternoon the section paid a visit to the 

 British United Shoe Machinery Co.'s works; a very excel- 

 lent descriptive pamphlet had been prepared in connection 

 with this visit, which was a most enjoyable one, and 

 enabled members to see to what an extent self-acting 

 machinery is now used in connection with the manufacture 

 of boots. 



The section did not meet on Saturday, but many of the 

 members spent the day in a visit to the Leicester and 

 Swannington Railway, one of the oldest railways in the 

 kingdom, constructed by George and Robert Stephenson ; 

 Mr. Clement Stretton acted as conductor of the party. 



Monday, as usual, was devoted to electrical papers, and 

 the first paper taken was by Sir William Preece, on the 

 Pupin mode of working trunk telephone lines. The author 

 stated that he himself had pointed out in 1896 that the 

 effect of electromagnetic induction in telephone wires was 

 in one sense beneficial, and that Prof. Pupin had made it 

 more beneficial in another sense, and had thus been able 

 to reduce the weight of copper used on trunk lines and 

 also to extend the distance to which ordinary speech is 

 practicable. Sir William Preece inspected in April last 

 the very successful work which has been done by the 

 New York Telephone Co. in connection with the adoption 

 of Prof. Pupin 's methods. The Pupin coil stores up a 

 portion of the energy, which, like a spring under pressure, 

 is ready to react on the release of the forced condition. 

 The size of the coils and their distance apart on the 

 circuit is a question of experiment ; Sir John Gavev has 

 found the best results with coils at every two miles; Mr. 

 Carty, on the other hand, employs them at every. i\ mile 

 on a long line, and at every J niile on a short line. The 

 author termed the addition of these inductance coils 

 " loading " the line, and he stated that the use of loaded 

 lines is increasing rapidly. In underground cables the 

 range of a loaded line is found in this country to be 

 2.4 times that of an unloadrd one. The application of 

 this principle to submarine caWes is now under investi- 

 gation, though it has not vet reached a practical stage. 

 In concluding his paper, the author pointed out that 

 telephone troubles in this country often arise from the 

 Tact that the subscriber is entirely ignorant of the system 

 NO. 1975, VOL. 76] 



of working, and will not take the trouble to make him- 

 self familiar with it. 



Sir Oliver Lodge read a short paper on tuning in wire- 

 less telegraphy, and described the system adopted in the 

 Lodge and Muirhead wireless telegraphy stations. 



Mr. J. T. Morris then read a note on an oscillographic 

 study of low-frequency oscillating arcs. The paper 

 collected together a number of observations which had 

 been made both with direct and alternating current arcs, 

 mainly with the object of studying the effect of a change 

 in the medium in which the arc is burning, and also to 

 e.Kamine the effect, if any, produced on the arc by the 

 application of a transverse magnetic field. No frequencies 

 of more than jooo were investigated. The pap^r was 

 fully illustrated by curves representing the results of the 

 experimental investigations. 



The next paper was by Mr. Leon Gaster, on develop- 

 ments in electric incandescent lamps. The author stated 

 that at the York meeting last year he had been able to 

 show a few sample no-volt metallic filament lamps con- 

 suming I watt per candle-power ; to-day such lamps were 

 ordinary commercial articles. A number of types of 

 metallic lamps were shown by the author, including 

 tantalum lamps, " Osram " lamps, in which tungsten is 

 employed, and a lamp known as the Helion lamp. In 

 the discussion Sir William Preece stated that he had 

 lately equipped his own house with Osram lamps of 105 

 voltage, and, in order to reduce the pressure from 220 

 volts to the necessary 105, he had put in an alternating- 

 current transformer, but the cost of this had been more 

 than met by the saving in the payment for current within 

 a year, and that tliougb he had put the lamps in in 

 January, 1906, none of them had so far needed replace- 

 ment. 



The business of the day concluded with a short paper 

 by Prof. E. G. Coker descriptive of the new engineering 

 laboratory at the City and Guilds of London Institute, 

 Finsbury. A new wing has been added to the college, in 

 which accommodation has been provided for an engineer- 

 ing laboratory, drawing offices, lecture rooms, &c. The 

 hydraulic section of the engineering laboratory contains a 

 long cast-iron channel, and all the necessary measuring 

 tanks and other appliances ; a number of hydraulic 

 machines have been installed. The engines in the heat 

 laboratory are all of moderate size, and in many cases 

 have been designed with special reference to research work. 

 This new laboratory will bring the teaching equipment at 

 Finsbury well up to date. 



Tuesday opened with two papers on ferro-concrete, one 

 by Mr. J. S. E. De Vesian and the other by Mr. W. 

 Noble Twelvetrees. Bo(h authors made extensive use of 

 the lantern, and showed a large number of slides illus- 

 trating the kind of work for which ferro-concrete has 

 been so far generally employed. It was interesting to find 

 that this method of construction is now rapidly making 

 its way in this country ; Mr. De Vesian showed in his 

 lantern-slides a number of big mills, granaries, &c., which 

 have recently been built in Great Britain on the Henne- 

 bique system of ferro-concrete. In the first portion of his 

 paper this author went fully into the specifications which 

 he uses in connection with the materials required in ferro- 

 concrete construction, and explained the tests he carries 

 out in connection with the Portland cement. 



Mr. Noble Twelvetrees showed a series of slides to 

 illustrate the use of reinforced concrete for such types of 

 construction as railway sleepers, standards for overhead 

 electric cables, &c., and he advocated the use of concrete 

 for preserving existing steel bridges, especially where they 

 are liable to the corrosive effect of locomotive fumes. 



Mr. Worby Beaumont followed with a paper on the 

 origin and production of corrugation of tramway rails; 

 he suggested various causes in explanation of this peculiar 

 phenomenon, but, though the paper led to an interesting 

 discussion, no speaker was able to throw any light upon 

 the real origin of this troublesome problem, which so 

 often worries the tramway engineer. 



Two other papers were dealt with by the section on 

 this day, one, by Mr. H. I. Brackenbury, on modern 

 machinery and its future developments, and the other, by 

 Mr. C. V. Drysdale, on resistance coils and their com- 

 parison. The latter author exhibited his ingenious 



