498 



NATURE 



[January 2, 1913 



from technicalities and permeated by a dry, literary 

 humour of its own. 



The address was followed by an important report, 

 the fifth of the Gaseous Explosions Committee, which 

 dealt chiefly with the radiation effects and the turbu- 

 lent motion of the gas charge in the cylinders of 

 internal combustion engines. In this account of a 

 large amount of new work carried out by different 

 members, the committee shows that turbulence plays 

 a most important part in determining the time of 

 ignition of the charge in high-speed engines, such as 

 are now used for motor-cars and aeroplanes, while 

 it also has a large effect on heat loss, although at 

 very high explosion temperatures the radiation effect 

 is of chief importance. 



In connection with this paper Prof. Harold Dixon 

 confirmed some of the results of the committee's 

 work in his account of the experiments on 

 coal dust explosions at Eskmeals conducted for the 

 Home Office. 



Prof. Thornton also described his experiments on 

 the igniton of gaseous mixtures by momentary arcs, 

 and indicated the safe limits for operating electrical 

 machinery in coal mines containing inflammable 

 gases. 



.^n important discussion with Section A on wireless 

 telegraphy commenced the proceedings on the Friday 

 morning. This joint meeting afforded an animated 

 discussion in which a number of speakers representing 

 both sections took part. K summary of the chief 

 matters of interest has already appeared in these 

 columns (December 12, p. 421), and it only remains to 

 mention that this meeting was the most successful 

 joint gathering of these sections in recent years. 



A paper immediately following, by Dr. Eccles and 

 Mr. A. J. Makower, dealt with the production of elec- 

 trical oscillations with spark-gaps immersed in running 

 liquids. Although it appears that the efficiencies are 

 about the same as that of an ordinary spark-gap in 

 air, yet the former have the advantage of being prac- 

 tically noiseless, a matter of some importance in large- 

 powered wireless stations. 



The impedance of telephone receivers was also dis- 

 cussed in a paper by Profs. Kennellv and Pierce, and 

 the effect of the motion of the diaphragm was 

 analysed in some detail. 



."Xnother electrical paper of great interest was con- 

 tributed by Prof. J. T. Morris, who described a method 

 of measuring wind velocities by the aid of a small 

 bare wire Wheatstone bridge having arms of manganin 

 and platinum. The cooling effect of a current of air 

 has no influence on the resistance of the manganin, 

 but it lowers the resistance of the platinum, and 

 an increased current is therefore required to effect a 

 balance. This change of current is a measure of the 

 velocity of flow of the air, as the author demonstrated 

 by lecture experiments. 



.\ discussion on the gas turbine, at the commence- 

 ment of the Monday meeting, was opened by Dr. 

 Dugald Clerk, who described the attempts which have 

 been made in recent vears to construct a successful gas 

 turbine. In particular, the performance of the large 

 turbine recently constructed by Herr Hans Hobzwarth 

 was analysed in some detail. Unfortunately, Herr 

 Hobzwarth was, at the last moment, prevented from 

 attending the discussion, and the details of his latest 

 improvements were not available. 



.■\n interesting group of papers dealing with motor- 

 car and aviation problems was headed bv a contribu- 

 tion from Sir John H. A. M.-icdonald, K.C.B., F.R.S., 

 on "The Road Problem," in which he described the 

 road-making methods of Macadam and Telford, and 

 the modern attempts to obtain a dustless and prac- 



NO. 2253, VOL. 90] 



tically indestructible road suitable for motor vehicles. 

 Various interesting experiments on the acceleration 

 and tractive power of motor-cars were described by 

 Mr. Wimperis, who, in the absence of the author, 

 Prof. Chatley, also gave a summary of a paper on 

 the control of aeroplanes. The results of experiments 

 ' at the East London College on the distribution of 

 pressure on inclined aerocurves were also described by 

 Mr. A. P. Thurston. 



A considerable portion of the sitting on the Tuesday 

 was devoted to naval problems, and the first paper was 

 a notable contribution on the suction between passing 

 vessels by Prof. Gibson, of University College, 

 Dundee, and Mr. Thompson, the engineer of the 

 Dundee Harbour Trust. Numerous experiments were 

 made with a fair-sized steam yacht, and a 30-foot 

 motor-boat running on parallel courses at speeds of 

 about six knots, and these showed that suction was 

 considerable, and rapid in action at lateral distances 

 of less than 100 feet. 



Prof. Henderson discussed problems in propulsion 

 by the aid of energy systems moving with the pro- 

 pelled body, and Mr. Mavor described some large new- 

 vessels fitted with his system of electrical transmission, 

 and showed the advances made since his paper of 

 last year. 



Mr. Axel Welin also described his system of lifeboat 

 lowering and raising gear, which is now being fitted 

 to numerous passenger vessels. 



Papers relating to the testing of materials were 

 taken on the concluding morning. 



Prof. Coker described some optical determinations 

 of the distribution of stress in plate and coiled springs, 

 and also the results of stress determinations by thermo- 

 electric methods. These latter have an advantage in 

 that they depend on the sum of the principal stresses 

 at a point, while optical measurements determine the 

 difference, and a combination of both methods was 

 advocated in certain cases. 



Mr. Haigh described an ingenious electro-magnetic 

 machine for obtaining repetitions of stress at fre- 

 quencies up to 120 per second, and Mr. Larard showed 

 some very fine kinematograph films of the fracture 

 of torsion specimens. 



Papers by Prof. Petavel and Dr. Lander were 

 also read during the meeting, describing experiments 

 on heat transmission, in which attention was 

 directed to the large convection losses of steam-pipe 

 coverings. 



Mr. R. S. Whipple described a F6ry bomb calori- 

 meter in which the rise of temperature due to com- 

 bustion is measured by thermo-couples, and the heat- 

 ing effect is absorbed by the metal, no water being 

 employed. 



Dr. Gray and Mr. Burnside gave an interesting 

 demonstration of their motor gyroscopes, and Prof. 

 Wilson gave an account of some exposure tests of 

 aluminium alloys, while Dr. Wall discussed the ques- 

 tion of hysteresis loss in iron due to pulsating and 

 rotating magnetic fields. 



Mr. T. Reid described a new form of rescue 

 apparatus for coal mines, and Dr. Owens contributed 

 a paper on the weathering of Portland stone. 



The section was well attended throughout, and the 

 discussions were well sustained. During the proceed- 

 ings the section heartily congratulated Sir William 

 White, K.C.B., F.R.S., a past-president of the section, 

 on his election to the presidency of the .Association 

 for the Birmingham meeting next year. It is interest- 

 ing to recall that in the last twenty-five years two 

 other distinguished engineers, Sir Frederick Bramwal 

 and Sir Douglas Galton, have filled the presidential 

 chair. E. G. C. 



