56 



NATURE 



[March ii, 19 :j 



anode circuit of the main valve. When variations 

 take place in the control anode at speech frequency, 

 very large surges are set up in that of the power 

 valve, which may approximate to the original high- 

 tension direct-current potential, and so sweep the 

 output from nearly double its steady value to zero. 

 The standard R.A.F. set is of the 20-watt size, with a 

 high-tension supply of 600 volts direct current. A great 

 advantage in the system for aeroplane work is that 

 no critical adjustments are required. The arrange- 

 ment of the apparatus is such that the set proper can 

 be mounted in any convenient position, and only a 

 very small control unit brought within reach of "the 

 user's hand. One switch makes or breaks the 

 dynamo field, filament, and microphone circuits- A 

 great deal of experiment was necessary before a suit- 

 able microphone was found, as it had to be almost 

 insensible to sounds of "noise " intensity, but respon- 

 sive to the powerful concentrated waves of a voice 

 impinging upon it at a very short distance. 



The receiving set depended upon high-frequencv 

 magnification, and was, in its first form, a three- 

 valve arrangement. It consisted essentially of a 

 detector valve with reaction and two note magnifica- 

 tions. The detector valve was not energised direct 

 from the aerial, but through an aperiodic circuit, 

 which was a circuit approximately syntonised by its 

 self-capacity. The final adjustment for obtaining the 

 best effect is made on a rheostat in the filament 

 circuit carried on the "joystick" itself. These three- 

 valve sets were employed to a considerable extent 

 both before and after the armistice, but a five-valve 

 receiver was developed later in which a choice was 

 made of two high-frequency magnifications and two 

 low, with a detector valve. This set was very much 

 more sensitive than the three-valve arrangement, and 

 enabled fixed aerials rigidly connected to the wings 

 and fuselage to replace the trailing aerial, which 

 latter was a great embarrassment in fighting. The 

 normal safe range of the apparatus is about four 

 miles from machine to machine, while the range to 

 a ground station is from twenty to fifty miles or 

 more. The author anticipates that in the future the 

 wireless apparatus will be able to be plugged through 

 on to the ordinary exchange lines, so that a man 

 sitting in his office will be able to hold a conversation 

 with a machine in the air. 



Magnetic Storm of March 4-5. 



TTHE Director of the Meteorological Office has 

 *■ been good enough to send us the subjoined com- 

 munication from Dr. Chree concerning a magnetic 

 storm which occurred on March 4 and 5. It may be 

 mentioned that on these days the sky was mostly 

 overcast in Scotland, though there was very fine 

 weather in the South of England. We are informed 

 that the only aurora observation reported so far was 

 made at Aberdeen at ih. 30m. on March 4, i.e. ten 

 hours before the "sudden commencement" of the 

 storm : — 



"A considerable magnetic disturbance was recorded 

 at Kew Observatory on the night of March 4-5. 



"There was a well-marked S.C. (sudden ' com- 

 mencement) at about iih. 40m. on March 4. This 

 was of an oscillatory character both in D (declination) 

 and H (horizontal force). The first, smaller, move- 

 ment was a fall in H and an easterly swing in D, the 

 range of the oscillation being about 457 in H and 

 7' in D. H retained an enhanced value for four or 

 five hours after the S.C, and no reallv large move- 

 ments occurred until after lyh. on March 4. The 

 most disturbed time was from i8h. on March 4 to 

 gh. on March 5. On the whole, H was falling from 



NO. 2628, VOL. 105] 



i7h. on March 4 until after 2h. on March 5, the 

 maximum being recorded at about i6h. 20m. on 

 March 4, the minimum at about 2h. 5m. on March 5, 

 and the range being approximately 3007. The H 

 curve had become quiet before loh. on March 5, but 

 still showed a depression of about 757. 



"The D trace was off the sheet, 'in the direction 

 answering to easterly displacement, for fully twenty 

 minutes between 22h. and 23h. on March 4; so the 

 range recorded, 60', may have been considerably ex- 

 ceeded. The maximum westerly displacement oc- 

 curred at about i8h. 3,;m. on March 4. 



"From i2^h. to \^\\\. on March 4 the D trace 

 was practically normal except that the declination was 

 \' or 2' more westerly than usual. Thus the dis- 

 turbance was rather a conspicuous example of the 

 lull that not infrequently intervenes between the S.C. 

 and movements that would be recognised as con- 

 stituting a magnetic storm." 



University and Educational Intelligence. 



Cambridge.— Mr. E. V. Appleton, of St. John's 

 College, has been appointed an assistant demonstrator 

 in experimental physics. 



It is proposed to confer the honorary degree of 

 D.Litt. on the Abbd Henri Breuil, professor of the 

 Institute of Human Palaeontology at Paris. 



It is proposed to- create a readership in the morpho- 

 logy of vertebrates and a lectureship in zoology in 

 place of the present readership in zoology. 



Besides additions and improvements to the chemical 

 laboratory and the erection of the Molteno Institute 

 for Parasitology, other building schemes are in view 

 for engineering, physics, and also for the University 

 library. The last proposal to meet the difficulty of 

 finding room for books was to excavate a large 

 underground chamber. The cost of this has been 

 found to be prohibitive, and the Senate has recently 

 discussed a revival of an old scheme to erect a new 

 building akin to the Senate House and on the south 

 side of Senate House Yard. If this scheme is adopted 

 a public appeal will be made for subscriptions towards 

 the erection of the building. 



Leeds. — Mr. W. E. H. Berwick has been appointed 

 lecturer in mathematics in the University. Mr. Ber- 

 wick was assistant lecturer in the University of 

 Bristol for two years, and afterwards became lecturer 

 in mathematics in University College, Bangor. For 

 two_ years he was engaged on the technical staff of the 

 Anti-Aircraft Experimental Section of the Munitions 

 Inventions Department at Portsmouth, where he made 

 important contributions to the experimental and com- 

 putative theory of gunnery. He has published a long 

 series of papers in the Proceedings of the London 

 Mathematical Society and elsewhere. 



Oxford. — Prof. R. A. Sampson, Astronomer Royal 

 for Scotland, has been appointed Halley lecturer for 

 1920. 



The governors and trustees of Tancred's student- 

 ships propose to elect a student in physic at Gonville 

 and Caius College, Cambridge, at Whitsuntide. The 

 annual value of the studentship is about 95Z. Par- 

 ticulars are obtainable from Mr. E. T. Gurdon, 

 28 Lincoln's Inn Fields, W.C.2. 



The sixth annual report of the Carnegie United 

 Kingdom Trust is an account of the work done by 

 the Trust in 1919, and contains a statement of income 

 and expenditure for the year. The committee had 

 hoped that the coming of peace would have brouffht 

 with it a great opportunity for institutions which 



