July 24, 1890] 



NATURE 



291 



I 



eminently the groups in which warning colours are pre- 

 dominant. So, also, the American and Eastern sections 

 of the genus Papilio which are both subjects of mimicry 

 and have all the other characteristics of protected groups 

 with warning colours, are all exquisitely beautiful, with 

 their rich green or crimson spots on a velvety black 

 ground. And if we turn to birds, in which, as there are 

 no known warning colours, all that are not protective 

 are supposed to be due to sexual selection, we find, 

 imong much that is beautiful, great numbers of the 

 harshest contrasts and most inharmonious combinations 

 of colour that it is possible to conceive. Such are the 

 blues and yellows and reds of the m acaws and of a great 

 number of other parrots ; the equally harsh colours of 

 the barbets and the toucans ; the contrasted blue and 

 purple or magenta and black of many of the chatterers. 

 In many of these, no doubt, the texture of the surface is 

 so delicate and the colours so bright and pure that we 

 cannot but admire the tints themselves, although it is 

 impossible to claim for the mode in which they are com- 

 bined even the rudiments of aesthetic beauty. On the 

 other hand, we find really beautiful combinations of 

 colour and marking where sexual selection has certainly 

 not come into play. Such are the exquisite tints and 

 patterns of the cones, cowries, olives, harps, volutes, 

 pectens, and innumerable other moUuscan shells ; while 

 many of the sea-anemones, and considerable numbers 

 of the caterpillars with warning colours, are equally 

 beautiful. 



Still more doubtful and more opposed to reasonable 

 probability is the statement that " our standards of beauty 

 are largely derived from the contemplation of the nume- 

 rous examples around us, which, strange as it may seem, 

 have been created by the aesthetic preferences of the 

 insect world"— alluding, of course, to the colours and 

 structures of flowers as being due to the need of attract- 

 ing insects to fertilize them. Here objection may be 

 taken, first, to the term preferences as applying to mere 

 beauty in the flower, and still more emphatically to the 

 term czsihetic, which there is not a particle of evidence 

 for believing to enter at all into an insect's very limited 

 mentality. Insects visit flowers wholly and solely, so far 

 as we know, to obtain food or other necessaries of their 

 existence, and every fact connected with the colours of 

 flowers can be explained as due to the advantage of con- 

 spicuousness amid surrounding foliage, and distinctness 

 from other flowers which are especially suited to different 

 species of insects. When cows and horses refuse to eat 

 the acrid buttercup, we do not say that the glaring 

 yellow colour is repugnant to their aesthetic sensibilities, 

 and that their dislike to the plant as food is the result ; 

 yet this would be less improbable than that bees and 

 butterflies have any admiration of or liking for flowers 

 independent of the supply of their physical wants. 

 Moreover, a large part of the beauty we see in flowers is 

 independent of colour, and is due to the graceful forms 

 of individual flowers, their elegant groupings, and their 

 charming contrast to the foliage which surrounds them. 

 We now know that much of the variety in the form and 

 position of flowers is dependent on their own physical 

 needs, the protection of the pollen and the germ from rain, 

 wind, or insect enemies, and that it has been produced by 

 natural selection acting under the limitations due to the 

 NO. 1082, VOL. 42] 



fundamental laws of vegetable growth. The purity and 

 intensity of the colours are due to the fact that such 

 colours offer a greater contrast to the ever-varying tints 

 of foliage, twig, and bark, seen under constant modifica- 

 tions of light and shade, than would be offered by more 

 sober hues ; and thus it is that flowers usually exhibit the 

 purest and brightest colours, which, combined with their 

 elegant or curious forms, and the exquisite setting of 

 green foliage which surrounds them, produce a general 

 effect Avhich is to us inexpressibly charming. But we 

 have no reason to believe that any of the lower animals 

 are affected in the smallest degree b/ these truly sesthetic 

 feelings, and the use of the term as applied to them 

 is simply begging the question, and is, therefore, not 

 scientific. """ 



It is because Mr. Poulton himself admits that the 

 theory of sexual selection is still to some extent sub 

 judice that the preceding remarks have been made in the 

 way of protest against the use of terms which themselves 

 tend to prejudge the case. In his chapters on this sub- 

 ject he has brought many arguments in its favour, some 

 of which are ingenious and novel ; but they all appear to 

 rest on very slender evidence or to admit of another in- 

 terpretation. They will, however, be useful as an incite- 

 ment to further observation on this most interesting 

 question, which, in all probability, will not be finally 

 settled by the present generation of naturalists. 



The book is well illustrated by numerous excellent 

 woodcuts and a coloured plate, and there appear to be 

 few if any misprints, the only one calling for remark 

 being the placing of the cut at p. 34 upside down, so that 

 the resemblance to a catkin is lost. Mr. Poulton is to be 

 congratulated on having produced so readable and sug- 

 gestive a volume on one of the most attractive depart- 

 ments of natural history, and on having by his own 

 researches contributed so largely to the solution of some 

 of the more interesting problems which it presents. 



Alfred R. Wallace. 



A HAND-BOOK OF ASTRONOMY. 

 Hand-book of Astronomy. Parts 1 1, and III. By George 

 F. Chambers, F.R.A.S. (Oxford : Clarendon Press, 

 1890.) 



T N commenting upon the first part of this revised 

 -^ edition of Mr. Chambers's " Descriptive and Prac- 

 tical Astronomy," we pointed out the utter insufficiency 

 of the portion devoted to the study of the sun, inasmuch 

 as it left solar spectroscopy altogether out of consideration. 

 Such an arrangement is a breach in the continuity of 

 scientific inquiry, and a grievous fault in a hand-book that 

 makes some pretence to give facts in historical sequence. 

 The second volume deals with instrumental and prac- 

 tical astronomy, and in it we find spectroscopical astro- 

 nomy interpolated ; the work that has been done in this 

 direction following the description of the instruments 

 employed. This circumstance, however, at once exhibits 

 an inconsistency, for, if spectroscopy properly follows a 

 description of the spectroscope, then telescopy should 

 follow a description of the telescope ; whereas in the 

 former volume the aspects of the heavenly bodies were 

 described, and in this the instruments by means of which 

 they are observed. 



