284 



NATURE 



[DECEMBE] i 2, 19 1 S 



I in book is reall) an introduction to medical 

 physiology, and might be of service to one who 

 desires to become a professional nurse, but is 

 quite unsuited to the requirements ol the 

 " Y.A.D." or emergenc) nurse R. T. II. 



The Student's Handbook of the I niversity and 



Colleges of Cambridge. Seventeenth edition. 



Pp. \ii-71-. (Cambridge: At the University 



Press, 1918.) Price 6s. net. 

 There arc three important additions to the 

 present issue of this very useful handbook. First, 

 tlu- regulations for the new diploma in Oriental 

 languages; secondly, the new regulations for the 

 Classical Tripos and the Oriental Languages 

 Tripos; and thirdly, the regulations for the newly 

 established Xita King; research scholarship fo 

 encourage research in the etiology, pathology, 

 and prevention oi fevers. 



An account is also given of the new Parlia- 

 mentary franchise for the University established 

 by the Act of this year. The war has, of course, 

 occasioned temporary emergency legislation on 

 the part of the University authorities, and the 

 various enactments are duly summarised. 



Parents .nu\ intending students will find here 

 all the information they seek concerning the 

 University and the different colleges. 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.] 



The Late Mr. R. P. Gregory. 



I\ supplement to Prof. Seward's sympathetic notice 

 of the late Mr. R. P. Gregorj in Nature of Novem- 

 ber 28, 1 venture to add .1 few words as to the peculiar 

 interest of his genetic work. Mr. Gregory was at first 

 associated with me in the proof that the familiar 

 heterostylism of Primulas is an allelomorphic pheno- 

 menon. He next undertook a laborious inquiry into 

 the sex-polymorphism of Valeriana dioica, but, in spite 

 of much experiment, the case proved intractable, and 

 little positive result was reached. About this time he 

 declined a lucrative post which would have, as he 

 feared, meant the practical abandonment of research, 

 and, undeterred by a rather disappointing experience, 

 he attacked several problems met with in the genetics 

 of Primula sinensis, to which he devoted his spare 

 energies for man} years. Mr. Gregory there encoun- 

 tered a group oi huts of surprising noveltj and im- 

 portance, which were described in outline' in Proc. 

 Roy. s " Ixxxvii.B, p. 4S4. Certain plants 



known in horticulture .as ••giants" have all their 

 organs of ver si; ■ . and two races of these are, 



as he proved ;ically, tetraploid, containing fout 



times (forty-eigl 1 the haploid number (twelve) of 

 normal plants. Breedinj from such plants, he hum. I 

 that the) are actuall; endowed with four sets of 

 Meiideli.m factors instead ol the usual two sets proper 

 to biparental inheritance. Various paradoxical con- 

 sequences were, therefore, theoreticalh possible, and 

 I of 'hi se, as he demonstrated, do occur. 



Such tetraploid plants are known to have arisen 

 de novo on two separate occasions (once in his own 

 N< >. 2563, VOL. I02] 



work and once at Messrs. Sutton's, to . hom be was 



indebti d u ilith si in lip 



as .Mr. Gregory discovered, the) wen 



with the races from which the\ were derived 

 a fact hitherto unparalleled and indubitably 



significance. When war broke out he became involved 

 in militan duties, eventuall) going out to France and 

 being rather hadh gassed. For technical reasons the 

 stud} hi the ' giants " had to be suspended, but he kept 

 always in touch with the Primula work, which we 

 maintained for him so far as possible. The purposi 

 Of the later experiments was to test thi theory that 

 the numerous linkages are indications .1 su 

 somatic segregations, a view to which he strongh 

 inclined in preference to current interpretations based 

 on cytologicaJ appearances, and he believed th 

 port for the somatic theory was alread\ in son* 

 measure provided b\ his own observations. He left a 

 mass of records bearing on this question, which we 

 hope eventually to publish, but the character and 

 soundness of his work even in its imperfect state gjvi 



it classical value. \V. Bateson. 



The John Innes Horticultural Institution, 

 Merton, S.W.19. 



Cyclonic Circulation. 

 I\ consideration of the theoretical or "gradient" 



wind associated with any system of isobars where the 

 curvature of the path is taken into account, a point 

 ol some interest appears to have been generally over- 

 looked in the past. In the stead) state the equation 

 connecting V, the velocity of the- gradient wind, with 

 y, the pressure gradient, is y D=2<oV sin o i V'cotp R. 

 where D=density of the air, w= angular velocity of 



the earth, '/. = latitude, R radius ol the earth, and 

 /1 = angular radius of the small circle which forms the 

 path of the air at the time. 



The positive or negative sign is to he 1 I en accord- 

 ing as the path is concave or convex to the low- 

 pressure area. For any given pressure gradient and 

 curvature of path there will be two roots for Y from 

 this equation that is, two different velocities, real or 

 imaginary, will satisf) tin- dynamical conditions. I be 



interesting case where the roots are imaginary has 

 been dealt with by Gold in his discussion of this ques- 

 tion some \ears ago (Meteorological Office, Official 

 Publication No. ran, 1908). In the ordinary cyclones 



and anticyclones with which we are familiar Y has 



the value given 1 > v the smaller numerically of the two 



nal mi. is, and the conditions pertaining to th' largei 

 root seem to have escaped attention. 



I ike a numerical example, let p = .>° and 



p = 55°; then, adopting the normal value for the 

 densit\ |), the equation incomes ±\ '+40-7. V 



afti iversion to the units m. sec. tor veloi 



ml>. per ich) km. for pressure gradient. To deal first 

 wiih 1 he case of curvature convex 10 the "low,'" 

 When the negative sign must he taken; putting 



1 mli. per 100 km., the two roots for "\ 

 ■ I and jt m. sec. Both roots have the sam< sign, and 

 correspond with clockwise rotation in the northern 

 hemisphere. In this case (anticyclonic motion) thi 

 larger of the two roots dees not seem to represent a 

 stable state, and am perturbation woujd li 

 modification of the whole pressun distribution. This 

 value is not, there tore, of prai tical interest, ["he lowei 

 value, 11 in, sec., is that which is met with in 1 



In the case < > f a path concave to the "low," th< 

 two roots for V arc- of opposite sign. The values 

 riding with the above pressure gradient are 

 \ ! 46 that is, V=6 m. sec. for normal 



counter-clockwise rotation, and Y = 4h m. sec. for 

 rotation in the opposite direction, i.e. clockwise in thi 



