5o8 



NATURE 



[August 17, 1916 



portance, and the committee will doubtless spare no 

 effort to ensure that it is actively continued and ex- 

 tended, and that in the future no risk shall be run of 

 this fundamentally important industry passing- into 

 foreign hands. Research on chemical and other 

 glasses has been done during the year by the labora- 

 tory, as well as by other institutions. 



As is well known, one of the principal difficultieis in 

 the manufacture of optical glass lies in the choice of 

 suitable refractory material for the pots in which it 

 is made. The report states that the research has so 

 far been mainly directed to the production of satis- 

 factory pots, and that similar work on heat-resisting 

 materials, and more generally on the behaviour of the 

 rare earths and other substances at high tempera- 

 tures, is of great importance in a large number of 

 industrial processes. For such work a technological 

 laboratory on a large scale is needed ; and notwith- 

 standing the economic diflficulties existing, it is to be 

 hoped that the matter will receive immediate and 

 serious consideration. 



The laboratory has earned a world-wide reputation 

 for its successful investigation of some of the more 

 difficult questions in aeronautics. The immediate 

 importance of the work to the Army and the Navy 

 has led to large additions to the equipment for 

 aeronautical research, for which new buildings have 

 been provided during the year ; in these a second 

 7-ft. and a second 4-ft. channel have been installed. 

 The laboratory has now five air-channels, as well as 

 a whirling table, available for experiments on 

 models, and with a greatly increased staff has been 

 continuously occupied in dealing with the questions 

 constantly arising in connection with the design of 

 new types of machine. In the investigation of light 

 alloys and materials of construction a large field of 

 work remains open, and it Is satisfactory to learn 

 that this branch of the work is receiving increased 

 attention on an extended scale. 



Provision for other new work has been rendered 

 possible through a timely gift from Sir Charles 

 Parsons. Arrangements have been made, at the 

 request of the Rontgen Society, for the examination 

 of materials employed for the protection of X-ray 

 workers. The equipment has been installed, and the 

 conditions of test are being determined in conjunc- 

 tion with the Council of the Rontgen Society. 



By desire of the Ministry of Munitions, arrange- 

 ments were made for the testing of prismatic com- 

 passes In considerable numbers. A paper describing 

 the methods employed was read before the Optical 

 Society. Assistance has been given to the Board of 

 Trade in preparing a specification of liquid compasses 

 for use on the lifeboats of merchant ships. The 

 examination of the luminous dials fitted on Instru- 

 ments for night use constitutes an important branch 

 of new test work, involving also the examination of 

 the luminous radium compounds employed. Tests of 

 radium preparations have been continued, and further 

 Improvements have been made In the methods of test- 

 ing optical pyrometers, which are now being manu- 

 factured in increasing numbers In this country. 



Turning to work which falls more appropriately 

 under the heading of research, an Investigation has 

 been made into methods of magnetic testing of 

 straight and curved bars, and improvements effected. 

 The work has been described in a paper presented 

 to the Institution of Electrical Engineers. A research 

 on magnet steels Is in progress. In the heat division 

 an appreciable amount of work has been done In 

 the investigation of the thermal conductivity of 

 various substances, both refractory materials for 

 furnace construction and materials employed for cold- 

 storage work. The rate of heat transmission through 

 roofing materials has also been investigated, and 

 NO. 2442, VOL. 97] 



found to depend to a much greater degree upon the 

 emissivity of the surface than on the rate of con- 

 duction through the material. The loss of heat 

 through special roofing material was thus found to 

 be 20 per cent, greater than that through galvanised 

 iron, owing to the difference in surface emissivity. 

 When the special material was painted with 

 aluminium paint, the transmission became practic- 

 ally identical with that of the sheet iron. Other 

 experiments on heat loss from surfaces have been 

 continued, and an investigation has been conducted 

 Into the qualities of British-made porcelain for pyro- 

 meter tubes. 



In the Optics Division, tables for the construction 

 of small telescope objectives from glasses of usual 

 types have been prepared and published at the request 

 of the Ministry of Munitions, and the results of con- 

 tinued experience and investigation in the design 

 and calculation of lens systems have been communi- 

 cated to the Physical Society in a series of papers. 

 Another Investigation relates to the improvement of 

 hydrogen vacuum tubes for use In the examination 

 of optical glasses. 



The Metrology Division has been closely occupied 

 with special test work. Some work relating to the 

 sizes of commercial sparking plugs and tapped holes 

 for motor engines has been carried out for the 

 Engineering Standards Committee. 



In the Engineering Department progress has been 

 made with a number of researches. A new machine 

 has been constructed for testing the endurance of 

 specimens under combined bending and twisting. 

 The methods of notched-bar impact testing have 

 been Investigated ; various methods for testing the 

 hardness and wearing properties of metals have been 

 compared, and experiments have been carried out on 

 the resistance of wood to reversals of stress. Shock 

 tests on railway couplings have been made. The 

 measurement of the rate of growth of cracks in the 

 Tower of London is a matter of general public 

 Interest. In Aeronautics the investigation of Btabilitj' 

 has been extended to the case of curvilinear motion. 



In the Metallurgy Department, investigatory work 

 has been mainly confined to matters of Immediate 

 importance ; some interesting papers relating tc 

 appliances for metallurgical research have been read 

 before the Institute of Metals. Valuable papers havf 

 been contributed to various Institutions by member; 

 of the staff of the Froude Tank, which has, however 

 also been occupied almost entirely with urgent wort 

 for the Admiralty. 



The report makes It clear that the laboratory h 

 borne its full share of the burden which has fall' 

 upon the nation, and the country Is indebted to t: 

 director and his staff for their strenuous efforts 

 the furtherance of technical efficiency. 



THE RECENT DEVELOPMENT OF 

 GERMAN AGRICULTURE. 



THE fact that on each hundred acres of cultivate 

 land Germany feeds seventy of her people whi' 

 Britain can only support forty-five has rightly receiv 

 wide publicitv In the daily Press. The memorandu 

 by Mr. T. H. Middleton, Assistant-Secretary, Bo. 

 of Agriculture and Fisheries, which explains how Gt 

 many does this, should be studied by all who ha 

 the welfare of British agriculture at heart. The tv 

 chief factors in the recent remarkable developrnent 

 German agriculture are her settled economic policy ai 

 her well-thought-out system of agricultural _ ed 

 cation. It was the belief that he was essential 

 the community, and that his land would not be aUo^^ 

 to go out of cultivation, rather than the extra pro 



