204 



NATURE 



[May 15, 1919 



which is the elementary or grammar school, the 

 hig-h school and the technical schools, and finally 

 the college or the university. " Education is 

 designed for the masses, and not for the classes," 

 so the author writes, and "it is the birthright 

 of every citizen." And so education becomes to 

 the American youth his one inalienable asset. 

 The author contrasts the enormous provision made 

 in the States with that made in this country in 

 the way of private benefaction and Government, 

 State, and city grants, not only in aid of general 

 education for all classes, but also in the means 

 of continued education and the support of re- 

 search as applied to agriculture and manufacture, 

 and especially refers to the great industrial and 

 commercial corporations which provide means for 

 the thorough education of their apprentices. 



The book is full of most interesting examples 

 of tTie varied ways in which education for, and 

 during the preliminary stages of, a vocation is 

 made accessible. Administrators of education 

 will find the book both a useful guide and a 

 much needed stimulus. 



Catalogue of Lewis's Medical and Scientific Circu- 

 lating Library, including a Classified Index of 

 Subjects, with the Names of those Authors 

 who have treated upon them. New edition, 

 revised to the end of 1917. Pp. 492. (London : 

 H. K. Lewis and Co., Ltd., 1918.) Price 

 12s. 6d. net. 

 This library catalogue is in two parts. A list of 

 the books arranged in the alphabetic sequence of 

 the authors' names occupies the greater part of 

 the volume, and is followed by an alphabetical 

 list of subjects. In the author index the title of 

 each book, its published price, and date of pub- 

 lication are given. Although the published price 

 may give some idea of the size of a book, it would 

 improve the catalogue if the number of pages in 

 each case were stated. We would also suggest 

 that for indicating the size of pages an approxi- 

 mate statement of the height and width of the 

 page in inches or centimetres is more useful as 

 well as more accurate than such expressions as 

 i2mo, cr. 8vo, and roy. 8vo. 



The second part of the catalogue Is Its most 

 Interesting feature. This is an alphabetical list 

 of subjects, the cross-references to the main list of 

 books being merely the names of authors. Thus 

 under "Molecules" we find Kelvin and Turner. 

 Turning to the author Index, we are led to Lord 

 Kelvin's lectures on "Molecular Dynamics" and 

 to W. E. S. Turner on "Molecular Association." 

 As there are thirteen Turners In the list. It would 

 have been better to give the author's initials in 

 the subject catalogue. Indeed, this should be 

 done whenever there are several authors with the 

 same surname. 



Although this catalogue has been compiled for 

 a particular library, it will be helpful to those 

 who are forming libraries of their own, the list 

 of modern scientific books In the English language 

 being very comprehensive. 



NO. 2585, VOL. 103] 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake to 

 return, or to correspond with the writers of, rejected manu- 

 scripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.} 



"Camouflage" of Ships in War. 



In his speech at the Royal Academy banquet the 

 Prince of Wales referred to one of the factors of 

 modern warfare which is of special scientific interest — 

 the art of "camouflage." In the highly successful 

 " camouflage " of ships as it was carried out during the 

 closing phases of the war the principle made use of 

 was that, familiar to biologists, of breaking up con- 

 tinuity of surface and outline by violent colour 

 contrasts. 



I happened to have become specially interested in 

 this problem of the "camouflage" of ships long before 

 the war through a peculiar concatenation of circum- 

 stances : — (i) I was professionally interested as a 

 biologist in the obliterative colouring of animals; 

 (2) during my sojourns in the Gran Chaco during the 

 years 1889-91 and 1896-97 I had had the extraordinary 

 efficiency of Nature's methods of obliterative colouring 

 constantly brought home to me by practical experi- 

 ence ; and (3) when present at the opening of the Kiel 

 Canal in 1895, as one of the crew of Mr. W. B. 

 Hardy's yacht Raven, I was particularly impressed 

 by the fact that, whereas the ships of the British 

 squadron attending the festivities retained their 

 beautiful colouring of cream funnels and black hulls, 

 the French and German warships, on the other hand, 

 had adopted an obliterative colouring of uniform grey 

 — the shade differing somewhat in the two cases. 



During more recent years, holding a consistent 

 belief in the impending war, I continued to interest 

 myself practically in the principles underlying the 

 visibility of ships at sea and the possibility of success- 

 ful " camouflage." After the outbreak of war, on my 

 return to Glasgow in September, 19 14, I proceeded 

 to endeavour to impress upon the Admiralty the con- 

 clusions at which I had arrived. These were briefly : — 



(i) That while it was not suggested that a ship 

 at sea under average conditions could be rendered 

 invisible in the strict sense, yet, on the other hand, it 

 was quite feasible (a) to diminish greatly the 

 conspicuousness of a distant ship, and (b) to stultify 

 the enemy's range-finders by confusing the details- 

 such as, above all, vertical lines — of which they make 

 use. It is unnecessary to recall that in range-finding 

 as applied to ships at sea there are two factors in- 

 volved : (a) the determination of distance, and (b) the 

 determination of the rate and direction of relative 

 movement. 



(2) That of the various methods which Nature 

 makes use of in her obliterative colouring of animals 

 there were two alone of practical value for applica- 

 tion to ships : (a) the contrast colouring already 

 alluded to, and (b) the method of compensative shad- 

 ing — the obliteration of relief by counteracting the 

 light and shade to which the appearance of relief in 

 large objects is mainly due. This latter method is 

 simplv the application of the great principle of animal 

 coloration which owes its recognition to the distin- 

 guished American artist, Mr. Abbott H. Thayer. 



I urged upon the Admiralty that, as a protection 

 against long-range gunfire, these two basic principles 

 should be applied to the colouring of ships. The hull 

 and the upper works were, as a preliminary, to be 

 treated on the Thayer principle, dark shadows being 

 lightened and high lights darkened, and then the 

 main protection applied in the form of strongly con- 



