Dec. 20, 1888] 



NATURE 



^1Z 



followed by instructions for the preparation and storage 

 of oxygen, which is now so commonly employed in con- 

 junction with hydrogen, or ordinary gas, for illuminating 

 purposes. The preparation of slides of every description, 

 micro-photography, and the process of making lantern en- 

 largements, are all fully considered. One chapter is also 

 devoted to the description of a few simple scientific ex- 

 periments, which can be easily performed whilst projected 

 on the screen. Finally, a few valuable hints are given to 

 aspiring lecturers or entertainers who wish to avail 

 themselves of the powers of the lantern. 



The necessary references to firms which supply par- 

 ticular appliances have been made without any partiality. 

 The addresses of such firms might have been given with 

 advantage. 



The book is full of practical hints from beginning to 

 end. It is very readable, and we can confidently recom- 

 mend it to all who are concerned with lantern matters 

 in any shape or form. 



Chemical Problems. By J. P. Grabfield, Ph.D., and P. 

 S. Bums, B.S. (Boston : D. C. Heath and Co., 1888). 

 The systematic part of this book occupies the first 

 forty-six pages, the remaining forty pages containing 

 reprints of examination papers. The first part contains 

 general information as to chemical calculations and such 

 matters, with some problems worked out which are likely 

 to be of service to the elementary student ; but there are a 

 few points that appear open to improvement. The word 

 reaction is used in its ordinary sense, and also to indicate 

 an equation without the figures that indicate the numbers 

 of the several molecules ; to adopt the words of the 

 authors, an equation is a balanced reaction. This 

 appears to be a needless perversion of the meaning of a 

 useful word. The student is told to " balance the re- 

 action " " by repeated trials " of numbers, a method that 

 is certainly very common, but entirely unscientific and 

 unnecessary— in short, a method of cramming, and not a 

 method of teaching. At p. 12 we read, without qualifica- 

 tion, " that the weights of all gases are to each other as 

 their molecular weights"; it would be very inconvenient 

 to the commercial maker of gases if the weights of 

 his productions were so restricted. At p. 5 the word 

 weight is used in yet another sense : "' If we divide the 

 7veight of any element in the molecule, multiplied by 100, 

 by the per cent, of that element, we will have the mole- 

 cular weight." This looseness of language would, we fear, 

 be confusing to most students and to many teachers. The 

 volume will be chiefly useful to those who are preparing 

 for the examinations indicated in the second part. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himselj responsible Jor opinions 



expressed by his correspondents. Neither can he under- I Darwinism 

 take to return, or to correspond with the writers of, ' 

 rejected manuscripts intended for this or any other part 

 of Nature. AV notice is taken of anonymous communi- 

 cations.^ 



The Recent Eruption at Vulcano. 



In a letter recently received here from Mr. Narlian at Lipari, 

 that gentleman mentions some interesting facts relating to the 

 recent eruption of Vulcano. Amongst others, he says that some 

 weeks since some fishermen crossing between Sicily and Vulcano 

 "found themselves in a boiling sea, the water bubbling up," 

 " pieces of pumice coming up through the water." It appears 

 also that the cable between Capo Milazzo and Lipari has been 

 broken at about the same place, which is marked by "large 

 rocks." He then says he has been unable to examine any of 

 the pieces of pumice said to have come from the bottom of the 

 sea. 



Whether we have evidence here of a submarine eruption or of 

 a fumarole it is difficult to decide, but further information we 



must hope will be forthcoming. It is possible that it is simply a 

 submarine fumarole or spring, similar to the Sorgente Le Caklaje, 

 which is met with in the sea at a point forming a triangle with 

 the islets of Lisca Bianca and Bottaro between Lipari and 

 Stromboli. 



The following is the latest information in regard to the 

 eruption of Vulcano (the letter is dated Lipari, December 12) : — 

 " Some weeks since, the crater itself showed signs of diminish- 

 ing activity. The eruptions are often at intervals of hours from 

 each other, and never of such violence. Some days ago, a 

 gentleman, Mr. Salino, says he had gone to the top of the 

 mountain and seen the interior. This gentleman assured me 

 that two-thirds of the old crater is filled up (he had visited the 

 place eighteen years ago !) ; there was an opening of about 100 

 metres m diameter in the north-east side of the crater. No lava 

 was seen." 



From this it appears that the eruption is diminishing ; that 

 probably this filling up of the crater is due to the construction of 

 a cone of eruption, or that it is being choked by the materials 

 ejected from the new opening in the north-east side. Of course 

 without examining the locality one can only conjecture what has 

 really taken place. H, J. Joh.nston-Lavis. 



Naples, December 15. 



Natural Selection and the Origin of Species. 



For the third time Mr. Thiselton Dyer announces that his 

 judgment is opposed to the theory of physiological selection. But 

 this is not the point that I am debating. I am not discussing the 

 merits of my theory, or endeavouring to influence the opinion of 

 a critic who, after having shown that he had not read my answer 

 to the criticisms which he triumphantly reproduced as never 

 having been answered, now tells us that he has " devoted a 

 good deal of time to the study of" my "views." From the first 

 I have restricted myself to meeting his specific allegations. Still 

 restricting myself to the same ground, I find that there are but 

 two points in his last letter which it is necessary for me to 

 consider. 



First, touching the inutility of some, as distinguished from the 

 alleged utility of all, specific characters, Mr. Thiselton Dyer 

 expresses impatience with me for putting what he regards as a 

 " strained interpretation " on Mr. Darwin's writings.^ Now, of 

 all things in the world, this is exactly what I should most wish 

 to avoid. But, rightly or wrongly, I am profoundly convinced 

 that such strained interpretation as there is, here lies on the 

 other side. Over and over again — and more and more emphatic- 

 r.lly the later the editions of his works — Mr. Darwin insists that 

 he doei not regard natural selection as the only agent which has 

 been concerned in the origination of species, and therefore con- 

 cludes — to quote only one additional passage from among many 

 to the same effect : " No doubt the definite action of changed 

 conditions, and the various causes of modification, lately specified, 

 have all produced an effect, probably a great effect, independently 

 of any advantage thus gained" ("Origin," p. 160). More- 

 over, towards the close of the last edition, he complains most 

 bitterly of " steady misrepresentation " with regard to this very 

 point (p. 421)— a complaint all the more forcible from its 

 presenting the only note of bitterness that is to be met with 

 through the whole range of his writings. Now, since his death, 

 this " steady misrepresentation " has continued, until the post- 

 Darwinian school have come to designate by the term "pure 

 the very doctrine which he here so vehemently 

 repudiates. 



This doctrine of utility as universal was very clearly enun- 

 ciated in his own life-time by Mr. Wallace, as " a necessary 

 deduction from the theory of natural selection " (" Contributions," 

 &c., p. 47), but. as just remarked, he expressly renounced it in 

 his section headed " Utilitarian Doctrine, how far true." There- 

 fore I say that, quite apart from all questions of biological 

 theory, or merely as a matter of historical fact, any chaise of 

 "strained interpretation" must here lie at the door of those 

 who seek to attribute to Mr. Darwin the opinions which have 

 always been held by Mr. Wallace, and which have now been 

 adopted by the school of Prof Weismann. Moreover, not 

 only is there no sense or reason in speaking of the passages in 



' He says : " Wh.it, however, I view with less patience th.in his unsustainert 

 generalizations, is his persisteni attempt to place them on the shoulders of the 

 Darwinian theory." Klsewhere, however, the crown aniJ front of his charge 

 is that I h.ave sought to shrivel up the Darwinian theory to verj- small dimcn- 

 sions-^nay, that I have roundly denied it altogether, if my words have any 

 meaning.^ How these contradictory criticisms we to be reconciled I must 

 leave their author to explain. 



