Nov. 17, 1887] 



NATURE 



53 



OUR BOOK SHELF. 



Manual of Mineralogy and Petrography, containing the 

 Elements of the Science of Minerals and Rocks. By 

 James D. Dana. Fourth Edition, Revised and En- 

 larged. Illustrated by numerous Woodcuts. (New York : 

 Wiley and Sons ; London : Triibner and Co., 1887.) 



That a new edition of this important and admirable 

 manual has been issued will be good news to all interested 

 in mineralogy, and especially to the teacher and student. 

 The book, which now consists of 517 pages, is well 

 arranged throughout, and contains, as all such books 

 should do, a full index. The whole body of mineralogical 

 science is here brought to focus, and the present edition, 

 in that part of it relating to the description of minerals, 

 is brought down to the year 1886, many new species 

 described during the past six years being included. The 

 chapter on rocks has been re-written, re-arranged, and 

 enlarged, and many illustrations are new. We would 

 suggest to the learned author that in the next edition a 

 chapter on meteorites and their mineralogy would form 

 an appropriate and much-valued addition. 



LETTERS TO THE EDITOR. 



\The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he ttnder- 

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

 rejected manuscripts. No notice is taken of anonymom 

 com mun ications. 



[ The Editor urgently requests correspondents to keep their 

 letters as short as possible. The pressure on his space 

 is so great that it is impossible otherwise to insure the 

 appearance even of communications containing interesting 

 and novel facts.'] 



"A Conspiracy of Silence." 



The article whir.h I contributed to the September number of 

 the Nineteenth Century, on the Coral Islands of the Pacific, has 

 done what I intended it to do. It has called wide attention to 

 the influence of mere authority in establishing erroneous theories 

 and in retarding the progress of scientific truth. The vehement 

 assault made upon it in the current number of the same review 

 by Prof. Huxley, and the article by Prof. Bonney in this journal, 

 are to me gratifying evidences of success. But both of these 

 writers are entirely wrong in the interpretation they put on a 

 few expressions in my paper. They interpret these expressions 

 as conveying imputations on the probity and honour of scientific 

 men in the habitual and wilful suppression or discouragement of 

 what they know to be truth. But there is nothing to justify 

 this interpretation. I have made no such accusation, and if any 

 one else were to make it 1 should join the two indignant Pro- 

 fessors in repudiating it. Scientific men are not only as good 

 as other men in this way, but generally a great deal better. 

 Prof. Huxley has been irritated by some "anonymous sermon," 

 which I have not seen and for which I am not responsible. He 

 admits that it is in this anonymous production that the 

 " slanders " against scientific men have taken the peculiarly 

 offensive form ; but he maintains that this unknown writer has 

 been "inspired" by my article on Coral Islands. On the 

 strength of this assumption — which may be true for aught I 

 know — he goes on through some seven pages to dissect certain 

 parts of my paper, and to read into it a great deal that is due to 

 his own excitement and to nothing else. 



I have no difficulty in expressing clearly and without any 

 circumlocution exactly what I do mean, and what I have intended 

 to say. Prof. Bonney interprets it very fairly, in abstract, when 

 he says that the moral of my paper is, "Beware of idolatry." 

 Some theory, hypothesis, or doctrine, is propounded by a great 

 man. It becomes established, partly perhaps by certain inherent 



elements of strength, or at all events of attractiveness. But soon 

 it stands unassailable, and unassailed, upon the vast foundations 

 of general acceptance and admitted authority. It becomes what 

 Prof Huxley on a celebrated occasion, and with at least a 

 momentary insight, called "a creed." The effect of such a 

 position is tremendous. Some men who see cause to doubt are 

 daunted. They keep silence. Others are prevented from even 

 thinking on the subject. A few who do think, and who do 

 doubt, and who do venture to express their doubts, are dis- 

 couraged and discountenanced. A great many others take 

 refuge in a suspended judgment, even after the production of 

 evidence which, in the absence of a " creed " and of authority, 

 would have been deemed conclusive. In all this there may be, 

 and in general there is, nothing worse than timidity on the part 

 of those who are the laggards, or the opponents, in some great 

 advance. It is more difficult for some men than for others to 

 face a prevalent opinion or an accepted doctrine. It is all very 

 well to say, as Prof Bonney says, that "to the man of 

 science truth is a pearl of great price, to buy which he is ready 

 to part with everything previously obtained." But scientific men 

 are human. They are, I admit, immensely superior to the 

 politicians, especially just now. But they have their failings, 

 and everyone who knows the history of science must be able to 

 call to mind not one instance only, but many instances, in which 

 the progress of knowledge has been delayed for long periods of 

 time by the powerful and repressive influences of authority, 

 exerted in one or other of many ways. 



My contention is that Darwin's theory on the origin of the 

 Coral Islands is a case in point. I believed in it or accepted it, 

 for many years, as others did. Prof. Bonney admits that I 

 have described it not only fairly, but as forcibly as if I were still 

 its advocate. This is exactly what I tried to do. I now hold 

 that it has been disproved, and has been replaced by another 

 theory quite as grand, and more in harmony with other natural 

 laws which are of universal operation, but have been only lately 

 recognized. I affirm, farther, that this new theory or explana- 

 tion has been received with the timidity, the discouragement, the 

 discountenance, and the obstruction which are characteristic in 

 such cases. That Dr. Geikie has supported it, is most 

 creditable to him. But his voice is not enough to di-prove the 

 truth of my contention. That Prof Huxley and Prof. 

 Bonney should be unable to make up their minds upon such 

 evidence as has been before us now for several years is, in my 

 opinion, a strong confirmation of the law which is operating 

 upon them. There are some discoveries in science — some ex- 

 planations of curious phenomena — which are self-luminous. 

 They shine with their own light. The moment they are sug- 

 gested, with a few cardinal and certain facts to illustrate them, 

 they are their own proof Everything that turns up speaks in 

 support of them. My conviction is that such is the character 

 of Mr. Murray's theory of the coral island formations in the 

 Pacific. 



Prof Huxley challenges me to re-affirm with better proof the 

 fact I allege — that Mr. Murray has met with discouragement. 

 I respond at once to that challenge. I have seen the letter from 

 Sir Wyville Thomson in which that naturalist urged and almost 

 insisted that Mr. Murray should withdraw the reading of his 

 papers on the subject from the Royal Society of Edinburgh. 

 This was in February 1877. No special reason was assigned, 

 but the terms of the letter indicate clearly that Sir Wyville 

 dreaded some injury to the scientific reputation of the body of 

 naturalists of whom he was the chief, and for whom, as con- 

 nected with the Challenger Expedition, he was in some degree 

 responsible. He had not himself at that time, I believe, fully 

 accepted the new doctrine. But that would have been no suf- 

 ficient reason for discouraging free discussion, if it were indeed 

 as free as it ought to be. In my article I understated the delay 

 which was thus occasioned. Three ye.-\rs, not two, elapsed 



