'October 22; i 



NATURE 



651 



additional by-products would be equal to that of the 

 sulphate of ammonia, and he stated that a good charcoal 

 •could be made direct from peat and the by-products re- 

 covered, and that a satisfactory process had been in 

 operation in Oldenberg for more than ten years. 



The second paper, on producer gas, by Mr. Emerson 

 Dowson, was noteworthy from the fact that the first 

 paper on this subject by the author was read at the York 

 meeting in 1881 ; the present paper contained a summary 

 of the progress which had been made during the last 

 quarter of a century. In concluding his paper, Mr. 

 Dowson dealt briefly with the two types of producers now 

 utilised for engine work. The suction plant cost less and 

 occupied less ground space, but the gas made in it was 

 not so strong as in the older form of pressure plant — in 

 some cases this advantage of the latter is important. He 

 stated that the fuel consumption per horse-power hour 

 and the labour required were about the same in both 

 types of plant, provided the steam required was raised by 

 means of an independent boiler. 



The third paper, by Mr. Robson, was entitled " The 

 Production of Cheap Power by Suction Gas Plants." The 

 author stated that the figures he was able to produce 

 showed that the modern gas engine and suction producer 

 could give power to small users and to large users more 

 cheaply than could be obtained by any other process. In 

 the form of a table he gave thre'e typical examples, one, 

 where the installation was 450 B.H.P., the total cost per 

 B.H.P. hour, allowing for depreciation and interest on 

 capital, worked out at o-205<J., and where the size of the 

 installation was only 20 B.H.P. the cost was o745d. Up 

 to the present suction producers had been made to work 

 on a commercial scale only with non-bituminous fuels, and 

 fortunately such fuels were easily obtainable in the in- 

 dustrial centres of this kingdom. The tar difficulty had 

 been the chief trouble in making a successful suction pro- 

 ducer work with bituminous fuels, as the apparatus re- 

 quired for the cleaning of the gas both increased the 

 frictional resistance of the passage of the gas from the 

 generator to the engine and destroyed the simplicity of 

 the arrangement. The author discussed several methods 

 by which this difficulty might, he considered, be over- 

 come. 



In the discussion on these papers, Mr. W. Crossley, 

 the well-known gas-engine maker, gave some interesting 

 figures his firm had obtained as the result of experiments 

 they had been carrying out on the utilisation of peat 

 with a peat containing 22 per cent, of N ; they esti- 

 mated that a profit of 5Z. 12s. per ton would be obtained 

 from the sulphate of ammonia, and with 1-6 per cent, 

 of N (about the average figure for Irish peat) the profit 

 would still be 4!. li. per ton of sulphate of ammonia 

 produced ; this practically meant that the power which 

 would be generated would cost nothing, and could, there- 

 fore, be retailed at a cost which would ensure the establish- 

 ment of industries requiring a large amount of power at 

 a low cost. 



The concluding paper for the day was by Mr. W. 

 Rosenhain, on the study of breakages. The author, after 

 emphasising the need of a careful study of every case 

 of breakage, if engineers were to obtain information 

 which would enable them to prevent the recurrence of 

 such breakages, stated that the causes of failure might 

 be classed into three different groups ; — (i) those due to 

 defects arising from the manufacture of the material of 

 construction ; (2) those arising from incorrect treatment 

 of the material during the process of construction ; and 

 (■3) those from defects arising during the life of the struc- 

 ture or machine. Mr. Rosenhain illustrated these three 

 cases by examples selected from invcstigfations which had 

 been carried out at the National Physical Laboratory. 

 The first case was that in which the inner tube of a large 

 gun had failed by internal cracks, and the microscopic 

 and mechanical tests showed that the failure was probably 

 due to a defect in the original steel ingot, viz. to its 

 contamination to an undue extent with enclosures of slag. 

 The second case was .a fr.artured locomotive crank pin ; 

 here the microscopic investigation pointed to the con- 

 clusion that a material of an originally satisfactory 

 character had been spoiled by a too severe hardening 

 process ; this example was a direct testimony to the value 



NO. 2034, VOL. 78] 



of microscopic observations in giving a clue to the thermal 

 history of a specimen of steel. The third case was a 

 broken shaft, where the investigation showed that the 

 coarse structure of the material in the central portion of 

 the cross-section of the shaft, which was undoubtedly the 

 cause of the fracture, had been present in the steel as 

 supplied by the manufacturer, and could not have been 

 produced as the result of vibration or working stresses. 

 Mr. Rosenhain "s paper was an extremely valuable one, 

 and indicated the good work which is being and can be 

 carried out in such an institution as the National Physical 

 Laboratory. 



A paper by Prof. E. Wilson, describing his further ex- 

 periments on the electrical conductivity of light aluminium 

 alloys as affected by exposure to London atmosphere, was 

 taken as read. 



The section opened its proceedings on Tuesday, Sep- 

 tember S, with a paper by Mr. F. W. Lanchester on 

 the laws of flight. The paper was illustrated by a number 

 of interesting experiments virith model aeroplanes. Mr. 

 Lanchester has been working on the subject for a number 

 of years, and has evolved mathematical expressions for 

 the path which is followed by a ballasted aeroplane and 

 for its stability ; generally speaking, the path is un- 

 dulating, and under certain conditions the aeroplane will 

 describe complete loops in the air. The mathematical 

 investigations into the stability of aeroplanes shovi^ed that 

 the velocity of flight must be considerable when the 

 machine was a large one, and therefore a large plane 

 required more power per lb. of weight than a small one, 

 thus limiting the weight of flying machines of the aero- 

 plane type. Mr. Lanchester directed attention to the fact 

 that there was not much to be gained from the study of 

 the flight of birds, carried out in the haphazard fashion 

 which had hitherto characterised such work ; he pointed 

 out, in particular, that it was only rarely that the observer 

 had ever recorded the weight of the birds the flight of 

 which he had been studying. In the course of the dis- 

 cussion Mr. Lanchester stated that, in his opinion, the 

 engine problem would not be simplified in the case of 

 large-sized aeroplanes, and he thought that the engines 

 would require to be air-cooled ; he had himself built a 

 considerable number of such engines, which worked quite 

 successfully. At the present time he was of opinion that 

 the best results would be obtained with a machine weigh- 

 ing, with its driver, not more than half a ton. 



The next paper was by Mr. F. A. Royce, on the causes 

 of wear in motor vehicle machinery ; the author dealt 

 with his subject under three heads : — (a) design ; 

 (6) material and workmanship; (c) lubrication and atten- 

 tion. To illustrate his first point examples of defective 

 designs in bearings were discussed and criticised, and in 

 connection with lubrication the importance of devices for 

 retaining the oil on parts subjected to friction, and of 

 always maintaining a film of oil between the rubbing 

 surfaces, was strongly emphasised. 



The last paper of the day was one by Sir Howard 

 Grubb, on clock-driving mechanisms for telescopes ; for 

 spectroscopic and photographic work with telescopes it was 

 necessary that the clock-driving mechanism should not 

 only drive the telescope at its normal rate, but also correct 

 any errors of position which might occur and would 

 accumulate. The problem — always a difficult one — had 

 been solved most satisfactorily by the use of electrical 

 control, and the author described the method adopted by 

 him for the 24-inch equatorial at Oxford University ; the 

 mechanism is, briefly, epicyclic gearing, which is operated 

 electrically, the necessary electrical contacts being- con- 

 trolled by a pendulum. In the discussion Dr. Rambaut, of 

 Oxford University Observatory, stated that the delicacy of 

 the adjustment obtained by this device was remarkable ; 

 the tube of the telescope was 22 feet 6 inches long, hence a 

 second of arc was represented by a linear measurement 

 of less than i/ioo millimetre, while in their photographic 

 work they aspired to keep the position of the images 

 true to 1/12,000 millimetre, and not only was the delicacy 

 of the adjustment so perfect, but the simplicity was equally 

 remarkable ; it was quite unusual for any adjustments to 

 be required. 



Oxving to the number of papers presented, the section 

 sat again on the morning of Wednesday, September 9, 



