214 



NATURE 



[April 15, 1920 



sary; (6) the right of any qualified teacher to teach 

 in any capacity in any State-aided school ; (7) no class 

 in any type of school to exceed thirty on the roll, and 

 each class to have its own qualified teacher ; and 

 (8) the curriculum of the primary school should 

 be liberal and non-vocational, with the aim of pro- 

 moting true citizenship and high personal character. 

 It was also suggested that the attention of public 

 opinion and of organisations representing parents of 

 elementary-school children should be directed to the 

 powers now possessed by persons interested in educa- 

 tion to secure substantial improvements in the educa- 

 tional facilities provided in their localities by means of 

 representations on the schemes prepared by local 

 education authorities under the Act of 1918, where 

 such schemes fail to attain the standard set up in the 

 foregoing proposals, and that county and local teachers' 

 associations should stimulate the demand for the full 

 benefits of the Act of 19 18 in each locality. 



A further important topic discussed at the confer- 

 ence was "The Supply and Training of Teachers." 

 The scheme submitted was approved by the con- 

 ference, and included the following main require- 

 ments : (i) All intending candidates should have com- 

 pleted a satisfactory course of higher education, and 

 •show by adequate tests their fitness for the profes- 

 sion ; (2) the admission to the graduate course should 

 be the standard of matriculation ; (3) the course of studv 

 should include "Education" as a principal subject 

 for the degree, and the course be followed in asso- 

 ciation with other students entering for other pro- 

 fessions; ^4) a period of one year should, as a rule, 

 "be devoted to the acquisition of skill in teaching, 

 the existing training colleges (which should be recog- 

 nised as colleges of the universitv) being utilised 

 for this purpose alone, whilst education rese<arch 

 work should be a distinct feature of the college staff 

 and students ; (5) on the completion of the academic 

 and professional traininff the teacher shouM be eligible 

 for recognition by the Board of Education for service 

 In any approved school ; and (6) the teachers of special 

 subjects should be required to take a course of higher 

 education and of professional training. 



Aeronautics at the Imperial Collegre. 



SIR RICHARD GL.VZEBROOK, the occupant of 

 the Zaharoff cha-ir of aeronautics at the Imperial 

 College of Science and Technology, completed on 

 March 24 the series of five lectures which initiate 

 the new course of study. It will be remembered 

 that Sir Basil Zaharoff founded similar chairs 

 in Paris and in Petrograd. The London chair has 

 been chosen by the Government as the nucleus 

 around which to organise a central school of aero- 

 nautics—a scheme in which the new professor's long 

 experience as Director of the National Physical 

 Laboratory, chairman of the Advisory Committee for 

 Aeronautics, and, latterly, chairman of the Govern- 

 ment Committee on Education and Research in Aero- 

 nautics, will be of immense help. In the years to 

 come the courses of instruction so provided will doubt- 

 less prove of service to officers of the Royal Air Force 

 selected bv the Air Ministry for higher technical train- 

 ing, in addition to such numbers of other students as 

 the then position of civil aviation may inspire to join 

 this new and adventurous profession. 



The attendance at this initial course of lectures 

 must have been encouraging to the lecturer, if only 

 as an indication of a widespread general interest in 

 the subject. In the circumstances, the lectures were, 



NO. 2633, VOL. 105] 



naturally and rightly, of a simple character, only the 

 last one, on air-screws, being at all technical. 



Sir Richard Glazebrook in his first lecture paid a 

 tribute to the munificence of the founder of his 

 chair, and proceeded to a description of the experi- 

 mental wind-channels and of full-scale experiments 

 on aircraft. He was able to show how, on Lord 

 Rayleigh's law of similarity, the measurements made 

 by the one method could be compared with the other. 

 The agreement in most cases was reasonably satis- 

 factory, though enough anomalies had been found to 

 provide an ample field for future research work. 

 This was followed by a lecture on the principles of 

 automatic and inherent stability. The former is 

 achieved by the use of auxiliary apparatus, whether 

 mechanical or aerodynamic, to operate the controls 

 of the machine ; and the latter by providing, in the 

 original design, such -sizes and positions for the 

 aerodynamic surfaces that any departure of the 

 machine from its normal position brings into ])lay 

 forces which tend to restore it to that position, and 

 create a "damping" couple sufificient to prevent 

 the continuance of such oscillations. Inherent 

 stabilitv can, as experience has amply shown, be 

 provided for by careful design, so that automatic 

 apparatus for the purpose is quite unnecessary. Com- 

 mercial machines should be decidedly stable, fig'hting 

 machines only just stable. Sir Richard Glazebrook 

 was able to show (with Mr. Nayler's assistance) a 

 number of mica models in flight, and so to illustrate 

 the various forms and degrees of stability and in- 

 stability. 



The third lecture was concerned with the instru- 

 ments essential to flight, and included the air-speed 

 indicator, the engine-revolution indicator, the alti- 

 meter, the clinometer (to indicate side slip), the stato- 

 scope (to show the rate of climb), and the turn 

 indicator. The statoscope measures the rate of air 

 leakage through a small hole in a vessel kept at a con- 

 stant temperature. Turn indicators are of two forms, 

 the static head type and the precessional gyro ttpe ; 

 these are later inventions than the other instruments 

 mentioned. 



Among the most important measurements made on 

 an aeroplane are the determinations of oscillation in 

 yaw, roll, and pitch ; for such experiments use can 

 conveniently be made of the sun as a fixed point, since 

 the motion of a shadow of some part of an aero- 

 plane on the rest of the machine can be employed 

 to obtain a photographic trace of the oscillations. 

 This work, however, is really only just beginning. 



In view of the enormous inertia forces which come 

 on a machine when "stunting," it is essential to 

 obtain a continuous record of their amount during 

 all parts of the flight-path concerned. For this pur- 

 pose a stiff fibre acted as an acceleration index, and 

 some most valuable records were obtained. On 

 occasion the force on the wings of the machine might 

 be three, or even four, times the weight of the aero- 

 plane. 



This naturally led in the fourth lecture to a con- 

 sideration of the strength of the wing structure and to 

 statements of the load factors necessarv in design. 

 The load factor is the ratio of the breaking load to 

 the normal load corresponding to horizontal straight 

 flight at the designed speed. Another important co- 

 efficient is the factor of safetv, and this is the ratio 

 of the breaking load to the loading incurred during 

 some specified operation, e.^. a vertical nose-dive. 

 The load factor needs to be fixed at a higher figure 

 for machines which, like fighting machines, have to 

 "stunt." 



Sir Richard Glazebrook's fifth and last lecture 

 was of special interest. The subject, " Air-Screws," 



