122 



NATURE 



[February 6, li 



seen would be represented by i ; and therefore from 

 these so-called " frequencies " we got a good idea of the 

 number of times we might expect to see any of these 

 disturbance-lines, when anything was going on in 

 the sun. 



It was this kind of work which made Tennyson write 

 those very beautiful lines : 



" Science reaches forth her arms 

 To feel from world to world " 



And then he added : 



" and charms 

 Her secret from the latest moon." 



I mention this because Tennyson, whose mind was 

 saturated with astronomy, had already grasped the fact 

 that what had already been done was a small matter 

 compared with what the spectroscope could do ; and now 

 the prophecy is already fulfilled, for by means of the 

 spectroscopic examination of the light from the stars we 

 can tell that some of them are double stars, that is to 

 say, in poetic language, stars with attendant moons. 

 Although we can thus charm the secret from each moon 

 by means of the spectroscope, to see the moon it would 

 require a telescope not 80 feet long, but with an object- 

 glass 80 feet in diameter, because the closer two stars are 

 together the greater must be the diameter of the object- 

 glass, independently of its focal-length and magnifying 

 power. 



{To be continued.) 



THE CAMBRIDGE NATURAL HISTORY.^ 



'T^HE second volume of this series (vol. v.) to make its 

 J- appearance is devoted, with the exception of articles 

 on the Prototracheata (pp. 3-26) and Myriapoda (pp. 

 28-80), to the Insecta, which will occupy also the whole 

 of vol. vi. 



Mr. Sedgwick gives a concise account of Peripatus, 

 which, being derived mainly from his own well-known 

 papers, does not call for extended notice ; the descriptions 

 of anatomy and development are written in a somewhat 

 technical style, but are not over-elaborated. If it were 

 thought necessary to reprint an easily-accessible list of 

 the known and doubtful species, it should certainly have 

 been revised. No records are noted since 1888 ; P. 

 hiliformis is given as a doubtful species, whereas at most 

 it is incompletely characterised, and P. trinidadensis 

 actually figures as " n. sp." A map, serving as frontis- 

 piece, shows the distribution ; but the records from Peru 

 and Chili seem scarcely to justify the inclusion of so 

 much of the arid western littoral of South America. 



Myriapoda are not a fascinating subject, but Mr. Sin- 

 clair's article, though slight and somewhat wanting in 

 style, gives many particulars of interest about them. 

 The author is clearly a morphologist rather than a 

 systematist, and has made a serious mistake in employ- 

 ing a classification so antiquated as that of Koch, who 

 knew little of extra-European forms, and whose characters, 

 if rightly transcribed, are far from accurate. Mr. Sinclair 

 prefers to disregard the work of systematists who have dealt 

 with separate families only ; but a system by Bollman of 

 the whole class (or classes, according to some specialists), 

 published in 1893 in Bulletin xlvi. of the United States 

 National Museum, has been overlooked. In the section on 

 development no mention is made of the reversal of the 

 embryo referred to on p. 216 of the work. This was a 

 matter for the editors, as is indeed the whole subject of 

 embryology. The details of early embryonic development 

 are so similar, that there is a risk of useless repetition 

 and of insufficient stress on points of difference unless 

 some co-operation is instituted among contributors. The 



• 1 " Peripatus, Myriapods, Insects." 

 D. Sharp. Pp. xii + 584. (London : 



figures of species are copied from Koch's " Die Myria- 

 poden," and, though the fact is not stated, that oiCermatia 

 variegata was drawn from an example which had lost 

 six pairs of legs ! 



In no branch of zoology has the influence of modern 

 morphological and biological research been of slower 

 growth than in entomology ; the subject is so complex, 

 so dominated by taxonomy and an unwieldy literature, that 

 few entomologists have the energy to leave their im- 

 mediate field of study in order to gain any general 

 knowledge of the natural history of insects. For this 

 the responsibility rests largely with the authors of the 

 many text-books on entomology, who for the most part 

 have been content to follow an antiquated method, basing 

 their work on a substructure of classification, and ignoring 

 families of the highest interest from all points of view 

 except those of the collector and systematist, in order to 

 fill their pages with a tedious procession of names and 

 useless details. 



For many years there has appeared no such valuable 

 or original work on insects as this of Dr. Sharp promises 

 to be, when completed. The author has rid himself of 

 the chains of the systematist, and has endeavoured, in 



NO. 1371, VOL. 55] 



By A. Sedgwick, F. G. Sinclair, and 

 Macmillan and Co., 1895.) 



Front of head-of Copiophora cornuta, female. Demerara. 



the most thorough and catholic spirit, to give a just view 

 of the many points of interest, whether in structure, 

 development or habits, which attach to this, the richest 

 class of the animal kingdom. 



In such a task, one does not look for novelty in 

 facts or theories, though there is ample evidence of 

 independent thought and investigation. It is in the 

 selection and treatment of subjects that Dr. Sharp's 

 originality is shown, and in these the book stands 

 absolutely alone. It is a real and new pleasure to read a 

 work of so broad a scope, in which so much is entirely 

 unknown except to the closest students of recent 

 literature, in which families such as Tkysanura, Henii- 

 meridce, Embiidce, or Termitidce are adequately treated, 

 and where due regard is paid to the writings of students 

 such as Brauer, Grassi, or Cholodkowsky. 



Though familiar insects are by no means neglected, 

 and much that is interesting and new is said even about 

 the earwig and cockroach, the number of strange and 

 rare forms discussed is quite extraordinary. No one 

 knows the literature of the subject better than the author, 



