5^2 



NATURE 



[February 28, 



iqii 



Waste— A World Problem," by Prof. H. J. Spooner. 

 The same firm also announces "Synthetic Products," 

 by A. R. J. Ramsey and H. C. Weston. 



Mr. Edward Arnold announces "Aeronautics in 

 Theory and Experiment," by W. L. Cowley and H. 

 Levy, in which will be chapters on the mathematical 

 theory of fluid motion, the aerofoil, structural parts 

 and controls, strength and construction, the air-screw, 

 and stability. 



OUR ASTRONOMICAL COLUMN. 



Nov^ IN THE Andromeda Nebula. — Including that 

 which appeared in 1885, five novae in the Great Andro- 

 meda Nebula have now beeri recorded. Two were 

 found by Ritchey on plates fallen in 1909, their maxi- 

 mum brightnesses being magnitudes 16-3 and 17-0 ; 

 these are no longer visible. Another nova, of mag- 

 nitude 17-5, at a distance of 10' from the nucleus, was 

 found by Shapley on photographs taken in September 

 last year. The latest discovery was made by Ritchey 

 on a negative taken on October 16, 1917 (Publications 

 Astr. Soc. of the Pacific, December, 1917). This star 

 was of about the i8th magnitude, and the distance from 

 the nucleus approximately 255" south and 26" west. 

 On this plate Mr. Shapley's nova was observed to have 

 diminished in brightness by at least two magnitudes 

 in the interval of a month. All the photographs in 

 question were taken with the 6o-in. reflector at Mt. 

 Wilson. 



New Varl-^ble Stars.— In Circular No. 201 of the 

 Harvard College Observatory Prof. E. C. Pickering 

 gives details of nineteen new variable stars which have 

 lately been discovered by photographic methods, and of 

 two which were found visually. The brightest images 

 observed range from 8-4 to 13-0, and the faintest from 

 8-8 to <i6. One of the variables is of the Algol type, 

 with a period of 2-89570 days, and two others are 

 Cepheids, with periods of 04786 day and 0365 day. 

 As illustrating the enormous wealth of material avail- 

 able for these investigations, the numbers of photo- 

 graphs examined with reference to the three stars 

 mentioned were 292, 537, and 350 respectively. 



Circular No. 202 gives the estimated dates during 

 1918 of maxima and minima of a large number of 

 long-,period variables. 



Two Spectroscopic Binaries.— The orbits of the 

 spectroscopic binaries 7 Phgenicis and a Puppis have 

 been investigated by Mr. R. E. Wilson with the aid 

 of photographs taken at Santiago, Chile (Lick Observa- 

 tory Bulletin, No. 303). 7 Phoenicis is a star of mag- 

 nitude 3-3. Class K5, and has been found to complete a 

 revolution in 19379 days, the orbit being essentially 

 circular. The semi-amplitude of the velocity-curve is 

 15-8 km., and the system is receding at the rate of 

 25-8 km. per sec. 7 "Phoenicis is the only late-type star 

 at present known to be moving in an orbit of very small 

 eccentricity, o- Puppis is of magnitude 2-99, Class K5, 

 and has a period of 257-8 days. The semi-amplitude is 

 18-55 km., and the velocity of recession of the system 

 87-3 km. In this case the eccentricity of the orbit is 

 0-17. 



Proper Motion Stars.— In Astronomische Nachrich- 

 ten, No. 4922, Dr. Max Wolf gives particulars of nine- 

 teen proper motion stars in the region of the Great 

 Andromeda Nebula, and of five which are near 8 

 Anetis. One of the latter is remarkable as showing 

 the jarge annual proper motion of 1-74*, in the direction 

 130 ; the star is of the 14th magnitude, and is situated 

 m R.A. 3h. 6m. los,, decl. +18° 23-1' (1875). 

 NO. 2522, VOL. 100] 



MILITARY AERONAUTICS. 

 JVJAJOR BAIRD, in introducing the Air Service. 

 ^** Estimates to the House of Commons on 

 February 22, gave an outline of the work which 

 had been done in creating the new Air Force. 

 The works and lands used by the R.F.C. 

 and R.N.A.S. have already been taken over, 

 and co-ordination between the Air Ministry, the War 

 Office, and the Admiralty has been secured by holding 

 weekly conferences of the three staffs. Among the 

 more interesting details of the speech from a scientific 

 point of view are the particulars which Major Baird 

 gave of the activities at the front. After all, the real 

 measure of the success of scientific investigation in 

 aeronautics at home is to be sought in the results 

 achieved in the fighting' area. These results were ex- 

 pressed in very concrete form in the speech, and we 

 quote some figures given. In one day on the 

 Western front 127 enemy batteries engaged were 

 I under aerial observation, twenty-eight gun-pits were 

 j destroyed, eighty more were damaged, and sixty explo- 

 I sions of ammunition were caused. In reconnaissance 

 I work nearly 16,000 photographs were taken in one 

 month. Our bombing machines, in short-range opera- 

 tions, dropped an average of 6500 bombs per month, 

 ^ representing a weight of about 120 tons. In addition 

 , to these activities, about 150,000 rounds of ammunition 

 j per month were used in attacking troops from the air. 

 ' Such figures as these cannot fail to awaken a sense of 

 the extreme importance of the Air Services in modern 

 warfare ; and the first item, viz. the destruction of 

 127 batteries in a single day, brings home in a very 

 i convincing manner the effectiveness of aircraft for the 

 j control of artillery. Major Baird warmly commended 

 I the work of the Advisory Committee for Aeronautics 

 j in furthering the technical side of the subject, and 

 I expressed the hope that its valuable labours would add 

 ! to the efficiency of the new Air Force in the future. 

 The speech met with an enthusiastic reception, which 

 it well deserved, for a more remarkable record of pro- 

 , gress in so new a branch of the Services could scarcely 

 [ be imagined. 



I La Nature for February 9 contains an interesting 

 article from the pen of Lieut. Jean Abel Lefranc under 

 the title "L'evolution de I'aviation allemande." The 

 author traces the general lines of development of 

 German machines since the beginning of the war. At 

 the commencement of hostilities the most prevalent 

 German type was a heavy biplane of very robust con- 

 struction as compared with the much lighter machines 

 developed in France. The main tendencies towards 

 improvement in this type have been directed towards 

 a reduction of head resistance by the simplification of 

 the lines of the machine, the adoption of stream-lined 

 fuselages made from three-ply wood, and the elimina- 

 tion of all unnecessary struts and tie-wires leading to 

 the very "clean" design of the present-day machines, 

 but necessitating a somewhat heavy construction. The 

 light single-seaters of the Nieuport type, against which 

 our enemies had to contend, led to the development of 

 the Fokker machine, which in turn gave place to the 

 Albatros DHL of the present time. The failure of 

 the Zeppelins to realise the aims of their inventor led 

 to the necessity of a heavy bombing machine, and the 

 development of this tApe has resulted' in the Gotha of 

 to-day. M. Lefranc points out the various technical 

 improvements made by the Germans as time went on, 

 such as the adoption of appropriate fin surfaces instead 

 of the large dihedral angle and swept-back wings of 

 the earlier machines, and the introduction of balanced 

 controls to obtain flexibility. The importance of 

 standardisation has been clearly recognised, and the 

 result is seen in the three main types now in use, re- 

 presented by the Albatros DHL, a light single-seater 



