( )i n IBER 14, 1922 ] 



NATURE 



525 



visits. The first lecture deall with the purpose and 

 methods of a museum, the nexl thirteen with various 

 forms of animal life, the fifteenth with the earl) 

 history of man, and the las! with the story of the 

 rocks and fossils. We undei tand thai othei Educa 



tun nmittees think of following tins excellenl 



example. 



Mr. II. E. Stone, of Sidcup, Kent, lias forwarded 

 to us a photograph "I .1 specimen oi Datura Stra- 

 in" a 1 um whii 1 1 has attained a height of 28 inches with 

 a foliage span of 58x24 inches, and bears 25 well- 

 developed seed-pods. The plan! is undoubtedly a 

 fine pecimen, although nol unusually large. The 

 largesl plants are often found on rubbish heaps made 

 up of garden nine and al o as weeds in cultivated 

 ground. Such plants benefil by their isolation as 

 much as by rich food material. Cultivated plants 

 are often allowed to stand too close together to be 



able to di \ eli ip to theii full extenl , « hile I h j u ualb 



lai 1. it ii fi iod materia] 3A ailable in the case oi 



isolated plants, ami pari ii 11 la rb I ho 1 thai ha vc sprung 



up as weeds 



I in 1 1 mi I' hi agi in •. oi t he Smithsonian [nstil u- 

 ti'in, Washington, which, since [871, has been carried 

 mi In Vlessrs. William Weslej and Sou, 28 Essex 

 treet, Strand, London, has been removed to the 

 premises oi the new firm oi .Messrs. Wheldon and 

 \\ ' |.\ , Ltd. (in William \\ eslej and 



Son), at _>, 5, and | Arthur Street, New Oxford Street, 



\V 1 .2. The large 1 il 1 ocieties, museum; . 



and institutions which forward their publicai 



for transmission bo theii i >rn 1 lents 



1 ho mgh the Iniei iiat ional E ■• 1 hange S) item oi 1 he 

 Smithsonian Institution are requested to forward 

 t heir con ignmenl 1 in the future to '., j, | Arthur 

 Street, Ni v, 1 txford Strei t, \\ .C.2. 



Our Astronomical Column. 



The Sunspoi Pi R • (ti Many attempts have 



been made to correlate the II year period ol spol 

 •, ,n iation v, nli the 1 1 -86 ■ ai period of Jupiter's 

 revolution. The latter, as i1 itand i, differs too 



widely, and it i ar t lane n w it I n 



other period. Prof. I . J. J. See, in a special number 

 i,l iii. .\,n In ., vol. •■ "' ai tempts to 1 ombine it 



with 9-93 years, whii h is thi pe I in whii h Jupiter 



gains a iei volution upon Saturn. He weights 



it,, ;e two periods in the ratio 1 -828 to 1, this ratio 

 being the square root oi thai oi Jupiter's mass to 

 Saturn's mass. The re nil is [i-i8 years, which is 

 close in the sunspoi pet iod, Bui if is to be noted 

 thai while the ri-86 yeai period depends whollj on 

 fupiter, thai oi g epends on both planei ., 



so that the appropriateness oi the above ratio is 



far fr ieai apa from this the re ul1 ing pei ii « I 



, a 1 v . 1 , ii,.,-. e ni' itions doe, not depend on the ratio 

 of their amplitudes, bui on the time thai one takes 

 to 1 .mi .1 revoluti >n on the oi her. For example, 1 he 

 pei iod 1 1 < mii spring tidi to 1 g tides is a temi 



Iim 1.1 1 n ni, and this would not be altered by an alteration 



in the relative hei r and lunai tides. 



It will be remembered that Prof. E. W. I'.roun 



also endeavoured to gel the sunspoi period from 



Jupiter and Sal um, 1 I" lUgh m a dillerent mi i 



He was sua essful in predicting that the 190; maximum 

 (vi ,uid be a late one. Mr. E. W. Maunder direi ted 

 attcntii ni to t be 1 \ clical hifl oi the spol 1 in olai 

 latitude syncbronou h with thi variation in activity, 

 which seems to indicate an interna] rather than an 

 1 xternal origin. 



Flam: ' Letter ro Richard Townelei 



'I In \ 1 \ ■ interes packel oi letters was recentl; 



found at the Royal Society. Dr. Dreyer contributes 



a long artii ie to the ( '- itot y £01 Septembei 



describing their principal contents \ few points 

 ,n,i\ bi unlit ii med here I lam bed was prompl in 

 .,, 1 1 pting Ri "in' 1 explanation oJ 1 he annual in 

 equality of Jupiter's latelliti due to the finite 

 velocity ol fight. He studied retraction at low 

 altitudes In measuring the change in the apparent 

 -.1 rtical diami ti 1 of the sun. 



\\'e I mil 1 1 "i 11 In notes on the K reat 1 01 net oi [680 



thai he wa a1 thai timi till a beCc* ei in 1 he vortio 

 -a 1 >esc artes, though he makes a note on New ton 

 different opinion. By t686 Flamsteed had apparentlj 

 become convinced oi the overthrow of the sj item 



NO. 2763, VOL. I IO] 



ni vori a es : aftei alluding to the pn igre is in 1 he 

 printing of the "Principia" he expresses his satis- 



ta< 1 1 the immense g tin thai thi new will 



.1 iiord in 1 hr ,1 in K . if 1 he plam tar) mol ions, " 1 ha I 



in the 1 if mourning I gratulate no own 



happini 



It is 1a 1 In-] melani hoi) to n< >te how hi 1 ipinion 

 oi I [alley graduallj 1 hanged from admiration to 



jea I- ai ■. ami iusp This seems to havi been 



largelj due to the associal 1 Halle) with Hooke, 



w iii mi 1 1. on teed 1 1 ni el' red an 1 main. 



We share Dr. Dreyer's hop.- that the letters will 

 be published in full. 



Per 1 1 rb \ .1 Wolf's Comet. Allusion was 



lati ly made in these note to the worl of M Kamensky 

 1 ai this 1 unlet from its disi oven in 18 (.to thi pn 



I line, and I" the lai gl I 1 1 . 1 1 1 '. its Orbii 111 ' I'. 1" 



,11 isi iii. 111 1 he \ ei \ lien approach to fupitei this 



1 1. 1 now 1 ali ulated thesi changi and 



gi 1 the results in .1 Jr. Journ. No. 807. The lea 1 



distani e oci urred on Si ptembei ■<■, w hen ii was 



i-eighth "i a unil , so thai J upiter's direi 1 ai 1 ii in 



was 1 .', times 1 ii.it iii t in .1111. .iii.l the as lumption oi 



elhpl n al motion < cases to lie I he small I appn . .una 



lion io the tint h. ( )n the ol in 1 hand, a remai I able 

 approximation ma bi obtained b 1 la 



motion to be m a in perl ".I ' abi iul I upiter, which is 



equivalent to 1 1 ea1 ing 1 1" acti 1 the un on the 



two bodies as identii al dui ing 1 be 1 ime 1 ii neai 

 approach, Incidentally tins gives an opportunity 



the equations for b.) perbolic motion, whii h 



in the icxt 1 1 lai vei eldoi pL iyed. 



1 he 1 : nlis obtained by thi \ imp! thod ai 



1 lose to those of the un »o rigorou in 



1 II pollll 1 , t ll.il thi pn ie I ba1 an- 

 al i 1 . [ual in izi bui opposite in direi tion to tho u 



.11 the appn ia< hoi [8; ;, so that thei omel n< iw return 

 \ca\ near] i orbii 1 la period is increased 



in mi 6 , : i" 8 I j eat '..and the perihel Ii ti 1 from 



1 ■ , 1 i, i i" ii fortunateh happen \ 1 ha1 a1 the 



Inai pa agi . 1925, Oct. 28. (., the 1 omel 



u Mi be aluii isi m opposition, thai the di itam e 

 from the earth will attain ii minimum value, 1-40. 



Prof. Kamensky hope, 1li.1t it m.i\ not be b I 



visual ni photographic reai h with large instr eni i 



if it should lie found, most of the credit will belong 

 to him; if nol seen then it will almost certainly be 



pi 1 in lb lost. 



