August, 1902.] 



KNOWLEDGE 



185 



risen above the destructive point, beyond which our experience 

 te;iches us that no organic life can exist. But "habitable" is 

 not synonymous with "inhabited,'' and Mr. Serviss wisely leaves 

 on one side the tjuesiion of the nature and form of the inhabitants 

 of other worlds, if such exist. In only one little whimsical 

 sketch, called " A Waif of S]>ace, ' does ho give free rein to his 

 imagination and describe a giant denizen of the minor planet 

 Menip])e. It is perhaps not quite fair to object to the description 

 as " not necessarily being true to life '' of an individu;U that he 

 has expressly told us can have no veritable existence, but we 

 think that he is generalising rashly when he describes the afore- 

 said individual as being thrce-<|uarters of a mile high. .S.S we 

 have said before, we can only know and study the laws of life 

 on this earth, an oblate spheroid whose eiiuatorial diameter is 

 about 71t:it) miles, and whose polar is 7899. Now it would never 

 enter our heads to attempt to deduce the latitude of a man's 

 home from his height ; we are very far indeed from finding 

 that the sons of Anak congregate round the pole ; nay, we 

 cannot find that anywhere is the scale of men inllueaced by the 

 locality. In equatorial Africa two races live side by side, and 

 the average height of one is almost double the average height of 

 the other, that is to say, the bulk of the giant man is some eight 

 times the bulk of the pigmy. Had we half-a-dozen worlds to 

 study, and the means of making a comparison of the scales on 

 which all their elephants, and all their men, and all their ants 

 are built, we might find some law connecting them with the 

 diameter of their world, but as it is, with but one poor earth to 

 reason from, there is not enough evidence to go before a jury. 

 Having described the probable physical conditions of the planets, 

 Mr. Serviss concludes his book by a very useful chapter on 

 " Uow to find the Planets, " which is illustrated by charts 

 showing naked-eye stars near which the planets may pass in 

 their course round the ecliptic. 



"ClKCUl.AR No. '.) OF THE ASTKOGRAPHIC CONFERENCE.'' — A 



considerable amount of literature is gathering round the work 

 of the Astrographic Chart and Catalogue ; the present Memoir 

 is chietly from the pen of M. Loewy and is for the purpose of 

 establishing the true correlation that exists between the 

 relative positions of the stellar images on the plates, and of the 

 corresponding stars in the sky. In the course of the investiga- 

 tion the following points have become evident : — In every plate, 

 whatever its diversity of exposure, the two feeblest magnitudes 

 of stars photographed only correspond imperfectly, both in 

 brightness and position, with the corresponding celestial objects. 

 The error of position is more notable than that which results 

 from the operation of measuring, and is due to the imperfect 

 sensibility of the gelatine to the feeblest beams of light. Star 

 trails do not give rise to any special error, but the source of 

 uncertainty mentioned above holds good for the faintest trails 

 just as for the faintest star discs. When the images of a 

 multiple exposure lie along a co-ordinate, the errors affecting 

 the other co-ordinate are much more notable than for that 

 passing through the line of images. The accuracy of the 

 measures of the second co-ordinate is not increased by utilising 

 more images. From the point of view of precision the weight 

 to be attached to measures along the first co-ordinate is double 

 that of the second. To render the precision of the measures 

 homogeneous in the two co-ordinates, the line joining the stellar 

 discs of a multiple exposure should bisect the angle between 

 the co-ordinates. M. Loewy is also of opinion that the 

 elongation of the images towards the borders of the plate does 

 not affect the accuracy of their measurement, at least in stars 

 above the limit of sensibility on the plate. In the preface, 

 M. Loewy refutes the argument of Mr. Plummer and Mr. Hinks 

 that systematic errors will be eliminated if the plates are 

 measured in two positions differing by an angle of 180°. A 

 notable systematic error is evident if the measures be compared 

 which are taken in positions of the plate at — ^ — and — ^^— 

 as he shows in the third Memoir of the present Circular. 



" OCCULTATIOXS OF StAES AND SOLAR EcLlPSES." By F. C. 



Penrose. Second Edition. (London : Macmillan & Co., Ltd. 

 190:;). — The first edition of Mr. Penrose's most valuable work 

 appeared in 1869, and in the present issue the work has been 

 much condensed and simplified as well as partially extended, 

 especially in the case of total solar eclipses. 'Thus the conditions 

 of totality for the total solar eclijise of January 2'i, 1898, as 

 .seen at Sahdol, in India, is one of the new diagrams. 



BOOKS RECEIVED. 



Dictionarii of Photographu. By K. .1. Wall, r.K.P s. (HazcU, 

 Waison & Viney.) Illustrated. 7s. 6d not. 



Gentle Art of Boole Lending. By George Somes Layard. 

 (Malvern Federated Library.) 



First Slai/c Mathe.iiatics (Organiso<l Science Series). Edited by 

 William Briggs. (University Tutorial I'ress.) 2s. 



Tear Book of I'hotoiiraphi/ and Amalcurs' Guide, 1902. {Photo- 

 graphic News Office. ) Is net. 



Plant Phtisiologi/. By William F. Ganong, I'H.d. (Boll.) 

 Illustrated. 5s. net. 



Injurious and Useful Insects. By L. C. Miall, P.K.s. (Bell.) 

 Illustrated. 3s. 6d. 



MetaHographq. By Arthur II. Hiorns. (Macmillan.) Illustrated. Gs. 



Studies in Belerogenesis. Second Part. By H. Charlton Bastian, 

 M.A., M.i)., P.H s. (Williams & Norgjite.) IlUistrated. 78. 6d. 



Wathins' Manual of Hrposure and Decelopmenl. By Alfred 

 Watkins. (Uoughton.) Is. net. 



Bulletins of the Unieersiiy of Kansas. Vol. IX., Nos. 1, 2, 3, -i, 

 and Vol. X., Nos. 1, 2, 3. (Kansas University.) 



Chaldean Astrolor/i/ Up to Date. By George Wdde. (Marsh- 

 Stile-..) 73. 6d. 



Miiiini/ in Rhodesia. (British South Africa Company.) 



Meteorological Obtervalions for 1901. (Bousdon Observatory.) 



Zoological Gardens, Ohizeh, near Cairo : Report for (he Tear 

 1901. Bv Stanlev S. Flower. (Cairo : National Printing Department.) 



Proce.ss Phot^iiram. .Tulv, 1902. 6d. 



Mew Phiitulog'ist. Vol. L, No. 6. Is. (M. 



Preparation of the Earth for Man's Abode By J. Logan Lobley, 

 F.G. s., F. R.G.s. (Victoria Institute Transactions.) 



Scientific Soil. By Alexander Ramsay. (R. L Sharland.) Is. 



Memorias i/ Revista de la Sociedad Cienfifica " Antonio Alzate." 

 XIII., Nos. 3 and -1; XVI., Nos. 2 and 3. 



Catalogue of Max Kohl, Chemnitz. (Isenthal & Co., sole agents for 

 the United Kingdom and its colonies.) 



Abridged Catalogue, 1902. (Ross, Limited, 111, New Bond Street.) 



Catalogue of Photographic Apparatus. (Sanders & Crowhurst, 

 71, Shaftesbury Avenue.) 



Catalogue No. 2. " Philosophical Apparatus." (Newton & Co.) 



THE NOBODIES-A SEA-FARING FAMILY. 



By the Rev. T. R. R. Stebbing, m.a., f.r.s., v.im,.s , f.z.s. 



CHAPTER IV. 

 If the Pycuogonida have, comparatively speaking, no 

 bodies and with an inconsiderate world no flaunting 

 reputation, they are by this time fully freed from the 

 hardship of having no names. With these they have 

 been abundantly blessed, though, when the names are 

 attended by definitions that leave them altogether indefinite, 

 the blessing is very much in disguise. More than forty 

 genera have been nominally established, but some of 

 them so obscurely that now and then a desperate author 

 pounds up eight or nine into one. Then again the 

 counsels of despair have to be modified, and some of the 

 rejected names resume their place in the system. 



There is, as naturalists are aware, a continual strife 

 being waged over classification. The philoso]>her is here 

 at one with the many. He desires and demands the 

 natural, the best, the permanent. The working zoologist 

 supplies only the imperfect and the transitory, based on a 

 disgraceful neglect of all those features and conditions 

 which at the time he happens to know nothing about. 

 His patient toil, his gradual acquisition of knowledge and 

 insight, bring him into more discredit. For he changes 

 his system to embrace the new facts, and with his old 

 perversity does not include in it the unknown and the un- 

 suspected. The history of the Pycuogonida is instructive 

 as showing that "all the talents," though they may 

 include industry, perspicacity, imagination, genius, are 

 incapable of producing a perfect classification until the 

 globe has been ransacked for materials and until the 

 materials themselves have been ransacked for informing 

 guidance. 



It has been already noted that the Pycuogonida are 



