November 23, 1899] 



NATURE 



^1 



uth Africa, presented by the Trustees of the South African 

 Museum; two Schalow's Touracous {Turactts schalowi), four 

 Cape Turtle "Dowss {Turtur capicola) from South Africa, pre- 

 sented by Mr. W. L. Sclater ; a Vulturine Eagle (Aqtiila 

 9trreat4xi) from South Africa, presented by the Rev. D. Kolbe ; 

 A Tawny Eagle {Aguila noevioides) from South Africa, pre- 

 sented by Mr. Claude Southey ; a White-tailed Gnu [Conno- 

 •ekae/us gnu, <J ) from South Africa, presented by Mr. C. D. 

 Rudd; two yi^x\^x\\\% (,Cynocepkaliis mormon, $$), two White- 

 collared Mangabeys (Cercocebus collarts, <J 9 ), a Tantalus 

 liloxiVey {Cercopithecus tantalus, $), a Lucan's Crested Eagle 

 {Lopkotriorckis lucani) from West Africa, a Spring-Bok 

 {Gazella euchore,^) from South Africa, a White-tailed Ichneu- 

 mon (fferpestes alktcauda) from the Atbara River, a Yellow- 

 headed Conure {Conurus jendaya) from South-east Brazil, four 

 Lesser Pin-tailed Sand-Grouse {Pterocles exustus), a Black- 

 headed Partridge (Caccahts viclanocephala) from Arabia, de- 

 posited ; a Roi Rhe-Bok {Cervicapra fulvo-rufula,$) ixoxn 

 Maryland, Schombie Station, Cape Colony, a Gannet {Sula 

 f>assana\ British, purchased. 



OUR ASTRONOMICAL COLUMN. 

 Holmes' Comet (1899 d). 



Ephetneris for I2h. Greenwich Mean Time. 

 Decl. 



1899. 



Nov. 23 

 24 



25 

 26 



27 

 28 

 29 

 30 



R.A. 



h. m. s. 



2 13 55-17 

 13 667 

 12 20-l6 



" 35 67 

 »o 53-25 

 10 12*94 



9 3475 

 2 8 5872 



-f47 40 0-2 



32 36-4 



25 17 



17 16-9 



9 22 s 



47 I 19-5 



46 53 8 '4 



+ 46 44 50*0 



Several observations of this 



Comet Giacobini (1899 e) 

 comet having been obtained, Herr S. K. Winther continues his 

 ephemeris in the Astronomische Nachrichtett (Bd. 150, No. 

 3600):— 



Ephemeris for I2h. Berlin Mean Time. 



Decl. 



Nov. 23 

 24 

 25 

 26 

 27 

 28 

 29 

 30 



-t-io 176 

 10 34-0 



10 50-5 



11 7-0 

 II 236 

 II 40-2 

 II 56-9 



+ 12 137 



0-50 



0-48 



R.A. 



h. m. s. 



17 52 33 



54 12 



55 52 

 57 32 



17 59 12 



18 o 52 

 o 2 33 



18 4 13 



During the week the comet pasSes from the northern part of 

 Ophinchus into Ilerculjes, about 6° east of a Ophinchi. 



Refraction Effect of Comet Swift (1899 I).— Prof. C. 

 D. Perrine, during May and June 1899, made several attempts 

 to determine if any appreciable refraction was caused by the 

 body of Swift's comet on a ray of light passing through it, and 

 contributes his conclusions to the Astronomische Nachrichten 

 (Bd. 150, No. 3602). The observations were made with the 

 36-inch Lick refractor, and consisted of determining accurately 

 the position angle and distance of two stars, (i) when one or 

 both of them were seen enveloped in the mass of the comet ; 

 (2) when quite free from the cometary matter. The diameter 

 of the head of the comet was computed to be about 174,000 

 miles, and the extent of matter traversed by the light from the 

 stars about 163,000 miles. The greatest range of variation in 

 the measured distance of the stars was o"-26, which the author 

 thinks in all probability accidental, as no systematic variation 

 was detected ; so that from these experiments the conclusion is 

 that the mass of a comet causes no appreciable effect of refrac- 

 tion on light passing through it. 



Predominance OF Spiral Nebuue.— In the Astronomische 

 Nachrichten (Bd. 150, No. 3601), Prof. J. E. Keeler describes the 

 preliminary results of his inquiry into the structure of nebulae. 



NO. 1569, VOL. 61] 



The discussion is based on photographs obtained with the 

 Crossley reflector of the Lick<)bservatory, and the author finds 

 that in addition to confirming the spiral structure of the nebulae 

 catalogued by the Earl of Rosse, so many others possess the 

 same characteristic form that their being put in a special 

 category loses its significance ; in fact, any small compact nebula 

 not showing evidence of spiral structure, appears exceptional. 

 He finds gradations leading to the belief that the elongated 

 spindle-.shaped nebulce of Herschel also really belong to this 

 class. The author concludes by stating that if numerous excep- 

 tions prove that spirality in nebulae is not an universal law, it may 

 perhaps be regarded as the usual or normal accompaniment of 

 contraction in cosmical masses, and any departure from it may 

 be explained as the result of special conditions, tending to 

 suspend or weaken causes which are generally in operation. 



Bulletin Astronomk^ue. — The Bulletin Astronomique 

 for November 1899 contains an illustrated article by M. Camille 

 Flammarion on the " Eclipses of the Twentieth Century visible 

 at Paris." Forty-three eclipses of the sun will be visible, two 

 of them being total, and thirty-three presented in good positions 

 for observation. The particulars of each are given, with a 

 diagram showing maximum phase. The same author describes 

 the observations of 339 Perseids made at Juvisy from 10-13 

 August 1899, with illustrations showing the plotted paths. The 

 mean position of the radiant was RA = 3h. 3m. ; Decl. -^56". — 

 M. Souleyre concludes his article on the " Distribution of rain 

 on the earth's surface. "—M. A. Benoit contributes a very interest- 

 ing article on " Transneptunian planets," giving particulars 

 respecting a proposed instrumental equipment for a systematic 

 search for such bodies. 



THE FITTING OF THE CYCLE TO ITS 

 RIDER.^ 

 'T'HE present time is opportune to notice some points in cycle 

 -*■ riding which have received our attention during the last 

 three years. Every intelligent rider of a cycle must have at 

 some time compared his powers as a human motor with the 

 motors that drive the motor- cars which he now so frequently 

 meets in the streets. He naturally wishes to study the question 

 of most efficient propulsion, including that of his own mechanical 

 efficiency as a motor driving his cycle. The design of the 

 modern cycle was so far developed by 1896 that a standard type 

 then became the rule, most cycles having a 45-inch wheel base, 

 two wheels of equal diameter 28 inches, cranks 6^ inches long, 

 and a ratio of gear varying between 59 to 80 inches, the sole 

 difference made between cycles intended for tall riders and those 

 for short ones consisting in varying the height of the frame. In 

 1896 the writers, being urged thereto by Mr. Otto Blathy, the 

 well-known engineer of Budapesth, had their attention called to 

 the necessity of varying the crank length to suit the varying 

 length of leg of the rider. A series of experiments was carried 

 out for cranks up to 9J inches long, and the results obtained 

 were very remarkable. It may now be taken as admitted that 

 a very large proportion of the riders who have tried cranks of 

 increased length have found great benefit from their use, but al- 

 though they feel strongly how tangible these advantages are, 

 some difficulty has been felt in satisfactorily explaining them. 



All that has been written on cycle riding in the past has been 

 confined to the style of riding which has been gradually elabor- 

 ated on cycles fitted with the standard 6i-inch to 6i-inch 

 cranks, but this is little or no assistance to us when we attempt 

 to investigate the subject through wider limits of muscular 

 movement. 



When mechanical engineers measure the efficiency of any 

 form of mechanical motor they confine themselves generally to 

 the consideration of the fuel that it con.sumes, but do not, as a 

 rule, when considering its efficiency, take into consideration the 

 cost of keeping it in repair, or include with it the cost of feeding 

 and maintaining the driver ; but the food which is the fuel of 

 the cycle rider has not only to perform the same duties as the 

 fuel of the mechanical motor, but has in addition to supply the 

 nerve waste and repair the muscle waste which answers to the 

 repairs to the mechanical motor, and from the same supply to 

 maintain the brain power of the driver. The food energy of 

 the cyclist has, therefore, to be distributed through three dis- 

 tinct channels : the first in importance is that which is required 

 I Abstract of paper read before the Cycle Engineers Institute at Bir- 

 mingham, by R. E. Crompton and C. Crompton. 



