October 27, 1910] 



NATURE 



553 



Mr. Cossar examined and described a remarkable series of 

 dry valleys which have resulted from glacial action. The 

 history of the rivers and their present economic value were 

 discussed, and then successively Mr. Cossar examined the 

 climate, vegetation, mineral resources, industries, occupa- 

 tions, and distribution of the population. 



Mr. O. G. S. Crawford's regional survey was of the 

 Andover district, which he discussed under the successive 

 headings of physical features, natural vegetation, industries, 

 including agriculture, settlements, and communications, 

 concluding with a survey of the reaction of man upon his 

 natural surroundings. 



Mr. H. Brodrick read a paper on the underground waters 

 of the Castleton district of Derbyshire. To the west of 

 Castleton is a long valley, in the base of which runs one 

 of the transverse Pennine faults which brings down the 

 carboniferous limestone, so that the streams to the north 

 run over the ^'oredale beds lo sink into the limestone. Of 

 the several streams, only one ends in a cave of any size, 

 the Giant's Hole. It was this stream principally that Mr. 

 Biodrick explored. 



Dr. C. -A. Hill read a paper on the further exploration 

 of the Mitchelstown caves in Ireland, carried out by him- 

 self and .Mr. Brodrick. \t the Dublin meeting in 1908 the 

 author gave an account of these caves, but since that date 

 an exhaustive survey of both caves has been carried out. 



Several papers of geographical interest were contributed 

 to other sections, but special attention must be directed to 

 the discussion, opened bv Prof. P. F. Kendall in Section C, 

 on the concealed coalfield of Nottingham. In the course of 

 his remarks Mr. Kendall announced that the coal measures 

 had been reached at Scunthorpe, eleven miles east of 

 Thorne. Borings are also in course of progress at Thorne, 

 Snaith, Selby, and Newark. This coalfield, he considered, 

 would be the hope and support of industrial England in the 

 future. 



KXGIXEERING AT THE BRITISH 

 ASSOCIATION. 

 T^HE first meeting of the engineering section was held 

 on Thursday, September i, when, in addition to the 

 president's address, only one paper was taken — the test- 

 ing of lathe tool steels, by Prof. Ripper. Two methods 

 of testing lathe tools are commonly employed ; in one, 

 the object of the test is to ascertain the length of time 

 the tool will run under given conditions before it has to 

 be reground : in the second, the object is to ascertain the 

 actual cutting speed which would entirely destroy the tool 

 in twenty minutes. Prof. Ripper was of opinion that 

 both these methods were of doubtful utility, the latter 

 because, in order to determine the standard speed, so 

 many tests had to be made. He had, therefore, devised 

 another method, which he called the speed-increment test. 

 In this method the tool was started at a standard cut — 

 at a surface speed of, say, 30 feet per minute — and the 

 speed of cutting was then gradually increased by equal 

 increments of i foot per minute until the tool broke 

 down. Prof. Ripper showed a number of curves to illus- 

 trate the results obtained by this method of testing, and, 

 after the reading of the paper, he gave a demonstration 

 in the University laboratory. The variation of the speed 

 was obtained by means of an electrical drive. 



The first business of the section on Friday, September 2, 

 was the discussion on the third report of the committee 

 on gaseous explosions. The chief e.xperimental work 

 undertaken by the members of the committee had been 

 the determination of the amount of radiation from fiames. 

 Prof. Callendar had experimented on the radiation from 

 open flames in the laboratory, and Prof. Hopkinson on 

 radiation from gases in a closed combustion chamber. 

 These experiments showed that a flame was, to a certain 

 extent, transparent to the same radiation that it emitted. 

 Prof. Callendar finding that two similar flames placed 

 one behind the other radiated nearly twice as much as a 

 single flame. Before the discussion opened. Prof. Dixon 

 described the experiments, he had recently carried out on 

 the ignition of gases by adiabatic compression. The gases 

 were rapidly compressed in closed glass tubes, and a con- 

 tinuous photograph was taken by means of rapidly moving 

 films. Prof. Dixon pointed out that it had been antici- 



NO. 2139, VOL. 84] 



pated that such gases would be uniformly heated, and 

 that they would, therefore, ignite simultaneously at all 

 points ; he did not, however, find this to be the case — 

 the explosion was never sharp nor violent ; the ignition 

 invariably began at one point, and then spread through- 

 out the tube. The discussion largely turned on the ques- 

 tion of the part played by radiation in regard to the 

 missing quantity in gas-engine heat balances. Captain 

 Sankey pointed out that the modern gas engine had an 

 efificiency of 80 per cent, to 90 per cent, when compared 

 with the standard theoretical gas engine, and that there 

 was thus only a loss of some 10 per cent, to 20 per cent., 

 there being, therefore, not much scope for further 

 improvement. 



The remaining business for the day was the reading by 

 Prof. Ripper of a paper on a new method of testing the 

 cutting quality of files. Until the invention of the Herbert 

 file-testing machine a few years ago, the only method of 

 testing the cutting power of files had been the hand tests 

 carried out by expert workmen. From some experiments 

 he had been asked to carry out, the author was of opinion 

 that the results obtained in the Herbert file-testing 

 machine were not normal, and he considered that this 

 machine had a serious defect ; owing to the fact that 

 the file moved across the face of the test bar through an 

 absolutely constant path, the teeth of the file, each stroke, 

 worked in identically the same grooves or furrows on the 

 face of the test bar, the result was that the surface of 

 the test bar became occasionally, as it were, glared, and 

 the file ceased to cut properly. With the view of over- 

 coming this defect, Prof. Ripper designed an addition to 

 the Herbert machine with the object of making the path 

 of the file no longer a constant one. To secure this result 

 the file was no longer held rigidly at each end, but was 

 connected by ball joints, the effect of which was equiva- 

 lent to the wrist movement at each end of the file during 

 ordinary hand-filing. The eccentric motion at one end of 

 the file was obtained by a worm gearing actuated by the 

 reciprocation of the machine. The author found that 

 with this addition the Herbert file-testing machine gave 

 extremely concordant results, and a number of curves 

 were shown to illustrate this point. After the conclusion 

 of the day's proceedings a demonstration of the machine 

 was given in the engineering laboratory. 



The section opened its proceedings on Monday with a 

 paper by Mr. P. Dawson on the electrification of the 

 London, Brighton and South Coast Railway between 

 Victoria and London Bridge. The author had been 

 responsible for the design of this important work. Bear- 

 ing in mind the possibility of future developments, he had 

 decided to adopt single-phase electric traction at 6700 volts, 

 with a periodicity of 25. The motors would develop lis 

 horse-power for one hour, with a rise of temperature of 

 only 70°, and 60 horse-power for twelve hours con- 

 tinuously under the same conditions ; there were four 

 motors to each car. Great trouble was experienced in 

 overcoming the difficulties due to the low head room at 

 certain of the overhead bridges ; thus while the normal 

 height of the overhead wires was 21 feet 6 inches above 

 rail-level, there was only available a height of 13 feet 

 9 inches at some of the bridges, and the collector bow 

 had to be adapted to this extreme variation in height. So 

 far the installation had proved entirely satisfactory. 



This paper was followed by one by Mr. H. E. Wimperls 

 on the use of an accelerometer in the measurement of 

 road resistance and horse-power. The accelerometer de- 

 signed by the author consists of a brass box, which con- 

 tains a copper disc mounted on a vertical pivot, with its 

 motions damped by a permanent magnet. The centre 

 of gravity of the disc is not in the axis, hence, when the 

 box moves forward, one side of the disc tends to lag 

 behind, and thus to wind up partially a coiled spring, and 

 so actuate a pointer moving over a scale. .An incenious 

 gearing prevents the reading from being affected by any 

 accelerations at right angles to the direction of motion. 

 By the use of this instrument road resistances can be 

 read off at sight, and the brake and indicated horse-power 

 of the engine can be obtained for various speeds. 



Prof. Coker next described his experiments on the 

 cyclical changes of temperature in a ffas-engine cylinder 

 near the walls : it was found that the highest temperature 



