59^ 



NATURE 



[July 7, 192 1 



For the convenience of members arriving on 

 Wednesday evening, September 7, who will have 

 only a short time at their disposal between the 

 time of their arrival and the inaugural meeting, 

 arrangements have been made with the station- 

 masters at the Caledonian and Waverley Stations 

 to establish inquiry offices of the Association at 



which membership tickets will be issued. These 

 offices will be opened at 5.30 p.m. for about an 

 hour and a half, but members who anticipate 

 arriving in Edinburgh after 5 p.m. would do well 

 to obtain their tickets by post beforehand so as 

 to avoid any congestion at these temporary 

 offices. 



Annual Visitation of the National Physical Laboratory. 



THE annual visit to the National Physical 

 Laboratory of the members of the General 

 Board took place on June 28. A large number of 

 guests were present, and were received by Prof. 

 C. S. Sherrington, president of the Royal Society, 

 the chairman of the General Board, and by the 

 director of the laboratory. Sir Joseph Petavel. 



An interesting ceremony preceded the visit, 

 when a bas-relief in bronze of the late director, 

 Sir Richard Glazebrook, was presented to the 

 laboratory. The presentation was made by Sir 

 Joseph Thomson, Master of Trinity College, Cam- 

 bridge, and received on behalf of the laboratory 

 by Prof. Sherrington. The bas-relief is the gift 

 of a large number of friends of the late director, 

 including many past and present members of the 

 General Board. 



It is now more than eighteen months since Sir 

 Richard was succeeded by Sir Joseph Petavel, 

 who has carried on very actively the work of his 

 predecessor. Some buildings planned in 191 8 are 

 still in process of erection at Teddington, and the 

 work of the laboratory continues to increase in 

 magnitude and importance. The Admiralty has 

 erected a research laboratory within the grovmds 

 of the National Physical Laboratory, so that much 

 of its special work may be carried on in close 

 co-operation with it. 



As on previous occasions of this kind, the 

 laboratory was thrown open to the visitors, who 

 Avere given an opportunity of seeing the work 

 that is at present being conducted in the various 

 departments. 



A wind tunnel of cross-sectional area 7 ft. bv 

 14 ft. has been completed during the course of 

 the current year, and affofds a valuable addition 

 to the equipment of the aerodynamics department. 

 In it a new method for the measurement of rotary 

 derivatives on an aeroplane was demonstrated. 

 Demonstrations in the other tunnels included the 

 measurement of the thrust and torque on an air- 

 screw working in front of a streamline body with 

 the simultaneous measurement of the drag on the 

 body; pressure plotting on an airship hull which 

 was carried out by means of a number of fine 

 steel tubes run longitudinally along the hull in 

 grooves and made flush with wax ; and the 

 measurement of lift, drag, and pitching moment 

 on a model aerofoil supported on wires and hung 

 from balances on the roof of the tunnel. Several 

 •"omplete models of aeroplanes were also exhibited. 



The engineering department exhibited a machine 

 presented to the laboratorv bv Mr. C. E. Stro- 

 NO. 2697, 'V'OL. TO7] 



meyer for the rapid determination of the fatigue 

 ranges of materials under reversals of shear- 

 stresses. Forced torsional vibrations are given 

 to the specimen under test by means of a rocking 

 arm and flywheel the mass of which can be 

 adjusted. The specimen acts as an clastic con- 

 straint between the rocking arm and the flywheel. 

 The usual method of finding the limiting range of 

 stress by endurance tests requires six specimens, 

 and, with the machine running continuously, 

 occupies a week. By the new method the limit- 

 ing range of stress can be found on a single 

 specimen by two independent means at the same 

 time, and the total time taken for the test varies 

 from five minutes to a quarter of an hour. 



In order to investigate the distribution of the 

 air currents produced by the present system of 

 ventilation in the debating chamber of the House 

 of Commons, a wood model (one-eighth full size) 

 has been constructed. Air is supplied to this 

 through ducts of the existing pattern from a fan, 

 the strength and direction of the air currents being 

 investigated by air-speed meters and smoke bands. 



An experimental range has been constructed for 

 the study of the motion of i-in. projectiles in 

 flight. The range is being fitted to carry this out 

 by a series .of "jump" cards, and also photo- 

 graphically by the spark method of Prof. Boys. 



Other exhibits in this department were the fol- 

 lowing : Apparatus for studying the effect of 

 pressure and temperature on the production of 

 detonation in a closed explosion vessel; apparatus 

 by means of which the temperature of the lubri- 

 cant, the load on the bearing, ana the speed of 

 the journal can be varied in order to obtain the 

 coefficient of friction of lubricants vmder varying 

 conditions ; apparatus for determining the dis- 

 tribution of frictional resistance over thin plates ; 

 and machines for various tension and compression 

 tests. 



A new apparatus for the autographic deter- 

 mination of changes in the electrical resistance of 

 alloys with varying temperatures up to and beyond 

 the melting point was exhibited in the metallurgy 

 department. A Morgan electric melting furnace, 

 in which a clay-lin^d graphitic crucible acted 

 simultaneously as the metal container and heat- 

 ing element, was shown in operation. Demonstra- 

 tions were given in the experimental rolling-mill, 

 illustrating the effect on the rolling properties of 

 certain non-ferrous alloys of unsuitable mechanical 

 and thermal treatment prior to the rolling opera- 

 tion. 



