December 8, 1892] 



NATURE 



27 



is advanced by the authorities quoted by Mr, Bateson which 

 can be rCjjarded as antagonistic to this impression by any one 

 who knows a little about the working of heredity in insect 

 varieties. 



A word about "showcases." I hope that no reader of 

 Naturk may be led to think lightly of these as a means of 

 instruction, and as one of the chief objects of a great museum, 

 because Mr. Bateson states that there is a wrong identification in 

 one at the Royal College of -Surgeons, and because of the distinc- 

 tion which he is .'■o careful to draw between these and other 

 cases. Some of the most valuable specimens in the world are in 

 "sliowcases." They form one of the most admirable features 

 in modern museum arrangement, and the best material obtainable 

 is set aside for them. This is equally true on the continent and 

 in our own country, where Prof. Sir W. Flower and Prof. 

 Stewart have devoted an immense amount of time and labour 

 to this department, an important recent feature of both their 

 museums being the illustration of the uses of colouring in 

 animals. Prof. Lankester too is developing the same method 

 of instaiction with great success in the Oxford Museum. 



It is in no way reaiarkable or reprehensible that four recent 

 writers (Mr. Lloyd Morgan, Mr. Beddard, Mr. Romanes, and 

 myself) concerned with this subject and knowing the care taken 

 in choosing these illustrations, should also make use of some of 

 them in their published works. 



One "difficulty" brought forward by Mr. Bateson is so 

 futile that I did not allude to it before, and only refer to it now 

 because he repeats it. He seems to think that doubt is thrown 

 on the theory of mimicry because V. pellticens does not resemble 

 a wasp, and yet lives in its nests — as if any believer in natural 

 selection maintained that all closely allied forms must defend 

 themselves in the same way I 



As to Mr. Bateson's statement at the end of his letter that he 

 only intended to draw attention to the matter (and not to hurt 

 me thereby), I can only say that this statement implies an 

 extraordinary want of acquaintance with the niceties of the 

 English language. It is so easy to correct mistakes without 

 leaving anything but a feeling of gratitude in the mind of one 

 who has made them, that, in justice fo Mr. Bateson's intelli- 

 gence, I am compelled to doubt the accuracy of his memory. 



Oxford, November 27. Edward B. Poulto.v. 



"A Criticism on Darwin." 

 I WRITE to protest against what appears to be a growing 

 habit on the part ot certain publishing tirms of advertising their 

 books in a most misleading manner, viz, by selecting any 

 l)hrase from a notice of the book which may serve to indicate 

 that the writer's opinion on the work as a whole is favourable, 

 whereas, if quoted with its immediate context, the passage would 

 prove the precise opposite. For example, I see in Nature and 

 elsewhere an advertisement of Mr. David Syme'sbook "On 

 the Modification of Organisms ; a Criticism of Darwin" (Simp- 

 kin, Marshall, and Co.), in which I am quoted as having called 

 the writer "a shrewd critic." Standing by itself these words 

 imply that I have somewhere recommended the work as well 

 worthy of perusal. The fact of the matter, however, is, that the 

 words occur in a foot note which I added to the proof of my re- 

 cently published book on " Darwin and After Darwin," for the 

 expressed purpose "of showing the extraordinary confuyion of 

 mind whicih still prevails on the part of Darwin's critics, even with 

 reference to the very fundamental parts of his theory." Else- 

 where in the same loot-note I refer to the writer's "almost 

 ludicrous misunderstandings " ; and conclude by saying that he 

 "shows himself a shrewd critic in some other parts of his e»say, 

 where he is not engaged especially on the theory of natural 

 selection." 1 may now add that the only parts of his essay 

 to which these advertised words apply are those where he 

 treats of the delttetious effects of in-breeding. 



George J. Ro.manes. 



Animals' Rights. 

 I AM not surprised that you should find my essay on 

 "Animals' Rights" an "absolutely useless" one, for I 

 certainly did not design it to be a congenial hand-book for the 

 apologists of Vivisection. Nor do I the least object to your 

 drawing what conclusions you like from the premisses laid 

 down by me, even thougli you seek your justification of 

 vivisection from the very definition that seems to me to be 

 most clearly condemnatory of it. But, as a mt^tter of fact, 



and not of personal opinion, I beg to point out that you have 

 utleily misiepresenled the leading principle of the book, and 

 that the two contradictory definitions of animals' rights, 

 which you attribute to nty confusion of mind, are in reality the 

 phantom creation of your own. On p. 9, in referring to 

 Herbert Spencer's definition of human rights, I claim for 

 animals a "due measuie" (not an equal amuuni)of the same 

 "restricted freedom" — a claim which by no means prohibits 

 all use and employment of animals, as you conveniently assume. 

 On p. 28 I give, not a second definition, but a repetition and 

 amplification of the one given on p, 9 ; and the "due measure 

 of restricted freedom" is explained as being "a life which 

 permits of the individual development, subject to the limita- 

 tions imposed bv the permanent needs and interests of the 

 community." Surely this is intelligible enough; yet the 

 reviewer has utterly failed to understand it. II. S. Salt. 



38 Gloucester Road, N.W,, November 26. 



Induction and Deduction. 



Miss Jones has not (juite understood me, I maintain that 

 definitiods sh mid be ar/iitrary, but not necessarily that they 

 should be made at random. If they are so made it will, as she 

 points out, seldom happen that they turn out useful, or have any 

 real applications, though this would not affect their logical 

 validity if it amused any one to make them and investigate their 

 consequences. Such definitions with no real applications are 

 actually made by pure mathematicians. The peculiar value of 

 the definitions of geometry consists however in the fact that 

 they have so many real applications, and it is only by a long pro- 

 cess of survival of the fitte-t that a few such happy definitions are 

 weeded out from among the many which lead to nought. The 

 definitions of geometry could not now be laid down at random, 

 but they are none the less arbitrary, for they require no support 

 from any ii priori considerations. Edward T. Dixon. 



Trinity College, Cambridge, November 28. 



NO. 1206, VOL. 47] 



The Present Comets. 



I have to notice the following mistake in my letter which 

 appeared in Nature (vol. xlvi. p. 561). I called comet Brooks, 

 comet "c." I now find it should be called comet "</'." 



I have since writing been quite satisfied that the head of 

 comet Swift extends less towards the n than towards the s (as 

 suggested in my letter). T. W. Backhouse. 



West Hendon House, Sunderland, November 26. 



The Afterglow. 



After witnessing, with Profs. Lyon and Orr, remarkable 

 effects of afterglow on November 27, I waited for the next issue 

 of Nature (No. 1205), in the expectation that similar phe- 

 nomena would be mentioned as having been seen in the British 

 Isles. Curiously enough, the letter on "Afterglow" in that 

 issue comes from Honolulu, dated November 8, It is possible, 

 however, that the effects of volcanic dust from one of the great 

 eruptions of the past summer are now beginning to be noticeable 

 in opposite hemispheres. The Krakaiab eruption of August 

 27, 1883, appears to have caused exceptional afterglows in 

 Honolulu on September 5, and in Western Europe by November 

 9, in the same year. 



From the top of Killiney Hill, on November 27, at 4 30 p m., 

 we witnessed an extraordinary combination of cloud-effects, 

 such as I do not remember having seen since the winter of 

 1883-4. On the west, dense clouds were forming upon Two 

 Rock Mountain, and streaming down into the hollow of Carrick- 

 mines ; but beyond them a clear golden sunset, passing above into 

 green and intense blue, was visible above the summits of the hills. 

 Fleecy cirrus clouds in the zenith were a delicate pink against 

 clear blue, and this glow extended to all the higher cloud- 

 mai-ses in the east, until the sea itself became rose-pink by re- 

 flection. But in the extreme east the exceptional magenta 

 tints, almost violet, that characterized many of the Krakaia() 

 glows, were strikingly apparent, though in part veiled by the 

 low grey cloud of the Channel. These effects were at their 

 maximum when the sun had set half an hour ; they would doubt- 

 less have been of much longer duration but for the near clouds 

 forming on the mountains. 



One's thoughts at once turned to the great eruption of Sangir 

 in the Philippines, which occurred, however, as far back as 



G 2 



