February 23, 1922] 



NATURE 



249 



(Pterophyllium scalare), the last two species new 



the collections. The report ot the secretary re- 



rded a considerable decrease in the number of 



sitors to the gardens in January as compared with 



numbers of the corresponding month last year. 

 |At a meeting of the council of the National Institute 

 .Agricultural Botany held on February 9 the first 

 :tion of fellows of the institute took place. A 

 idred and ten candidates were elected, among 

 iom were the following : — H.R.H. the Duke of 

 rk, the Prime Minister, the Duke of Bedford, the 

 irquess of Crewe, the Earl of Ancaster, the Earl 

 Derby, the Earl of Crawford, Viscount Milner, 

 jrd Clinton, Lord Bledisloe, Lord Ernie, Sir Gilbert 

 reenall, Sir Harry Verney, Sir Matthew Wallace, 

 Hon. E. G. Strutt, the Right Hon. E. C. Prety- 

 m, M.P., the Right Hon. Sir A. Grif^ith- 

 )scawen, Sir Thomas Middleton, Mr. Charles 

 ieane, Mr. Samuel Farmer, Mr. R. R. Robbins, 

 id Lady Margaret Boscawen. 



The officers and other members of council of the 

 [alacological Society of London for the ensuing year 

 t-ere elected on February 10 as follows : — President : 



Mr. A. S. Kennard. Vice-Presidents : Mr. J. R. le B. 



Tomlin, Prof. A. E. Boycott, Mr. G. K. Gude, and 



Mr. C. Oldham. Treasurer: Mr. R. Bullen Newton. 



Editor: Mr. B. B. Woodward. Secretary: Mr. A. E. 



Salisbury. Other Members of Council: Dr. A. H. 



Cooke, Mr. H. O. N. Shaw, Lt.-Col. A. J. Peile, 



Mr. T. Iredale, Dr. E. W. Bowell, and Mr. Hugh 



Watson. 



On Thursday next, March 2, Prof. H. M. Lefroy 

 will deliver the first of two lectures at the Royal 

 Institution on (i) "The Menace of the Insect Pest" 

 and (2) "The Balance of Life in Relation to Insect 

 Pest Control." On Saturday, March 4, Sir Ernest 

 Rutherford will begin a course of six lectures on radio- 

 activity. The Friday evening discourse on March 3 

 will be delivered by Dr. C. Morley Wenyon on " Micro- 

 scopic Parasites and their Carriers." 



Dr. W. Bateson, director of the John Innes 

 Horticultural Institution, Mostyn Road, Merton, 

 S.W.19, is giving a demonstration of the genetics of 

 Primula sinensis at the institution to-day, February 23, 

 at 3 p.m. All interested in the subject are invited, 

 and in particular those who attended Dr. Bateson 's 

 lectures on genetics in November last. Admission is 

 free, without ticket. 



The ninth election to Beit fellowships for scientific 

 research will take place in July next. Applications 

 must be received by the Rector, Imperial College of 

 Science and Technology, South Kensington, S.W.7, 

 not later than April 19. Forms of application and 

 all information respecting the fellowships are obtain- 

 able from the Rector of the Imperial College of 

 Science and Technology upon written request. 



The first award of the Meldola medal, referred 

 to in Nature of January 12, p. 49, has been made by 

 the council of the Institute of Chemistry, with the 

 concurrence of Dr. Percy E. Spielmann, represent- 

 ing the Maccabaeans, to Dr. Christopher Kelk Ingold. 



Our Astronomical Column. 



Detonating Fireball in Sunshine.— Mr. W. F. 

 Denning writes that this object observed by him on 

 February 7 at 3.55 p.m. appears to have been seen 

 by comparatively few observers, although the loud 

 detonations which followed it were heard by large 

 numbers of people, chiefly in Warwickshire, over 

 which county the fireball passed. It seems to have 

 caused the loudest reports near the middle section 

 of its flight, in the region of Quinton, Feckenham, 

 Mere Hall, and Droitwich. At some places there was 

 only one sound heard, at others two, but all the 

 observers agree that the concussion and vibration 

 were of startling intensity. The detonations were 

 heard along a line directed from S.E. to N.W. 

 The radiant point of the meteor was at 60°- 11°, and 

 the height from 56 to 32 miles ; the length of 

 luminous flight was 82 miles, and velocity about 10 

 miles per second. The position of the object was 

 from over Oxfordshire to Shropshire. 



Movements in Spiral Nebulae.— In this column 

 for January 12 reference was made to the movements 

 in spiral nebulae which Dr. Jeans described at the 

 Royal Astronomical Society when exhibiting slides 

 sent by Dr. van Maanen. Dr. van Maanen has now 

 published the fifth paper on this subject in the issue 

 of the Astrophysical Journal for December last, show- 

 ing the results of his investigation with regard to the 

 -piral nebula Messier 81. This paper contains the 

 vidence on internal motions derived from the four 

 iKbulai which Dr. van Maanen has now measured, 

 namely, M 101, 33, 51, and 81, and he summarises 

 the results in a table of which the following is an 

 NO. 2730, VOL. 109] 



abstract. The second column gives the interval in 

 years between pairs of photographs he has compared, 

 and the following four columns the motions as indi- 

 cated at the heads of the columns. The last column 

 gives the number of nebular points the positions of 

 which were independently measured : — 



(Units for Motions 0001".) 



Inierval Rota- 

 Object in years tional Radial Stream 



M lOI 5 +21 + 5 +21 



M loi 9 +20 + 6 +22 



No. of 

 Trans- nebular 

 verse points 



o 87 



-3 69 



M loi 15 +12 +7 +14 +2 46 



M 33 10 +20 + 6 +24 - 2 30 



M 33 5 +14 +12 +18 +4 21 



M 51 II +19+8 +21 +3 79 



M 81 6 +20 +17 +25 +16 52 



M 81 II +38 +13 +39 + 7 104 



It will be seen that all pairs of plates show the same 

 type of motion, and, as Dr. van Maanen points out, 

 the agreement in the values of the motion for each 

 nebula derived from different pairs of plates is as 

 satisfactory as could be expected. In addition to the 

 rotational ' components, which correspond to the 

 periods in the order of the nebulae in the table, 

 namely, 85,000, 160,000, 45,000 and 58,000 years, they 

 all show a large outward radial component. The 

 close agreement of the displacements in direction with 

 the spiral arms of the nebulae suggests, as he states, 

 "a realisation of the motions described by Jeans in 

 'Problems of Cosmogonv and Stellar Dynamics.'" 



