May 15, 1919] 



NATURE 



205 



trasting pigments, the boundary lines between the 

 colours running uninterruptedly across boats, guns, 

 turrets, etc. Of course, precisely the same principles 

 apply to ships viewed through the periscope of a sub- 

 manne, but in these early days of the war the sub- 

 marine menace had not yet become insistent. The 

 main principles outlined above were duly recognised 

 by the Admiralty, one of my letters on the subject 

 written in September being circulated to the Fleet 

 early in November, 19 14. Most unfortunately, their 

 carrying into effect was left to the responsibility of the 

 naval officers immediately concerned, without any 

 scientific or artistic supervision. The result was a 

 complete absence of system, and an effect in individual 

 cases calculated to excite, according to one's tempera- 

 ment, derision or tears. In the summer of 1915 I was 

 informed that the principle of parti-colouring had been 

 given up, that the Admiralty had now arrived at a 

 definite decision as to " the most serviceable scheme 

 of colouring for H.M. ships," and that this scheme 

 was one of uniform coloration. 



I continued to press on the Government — incidentally 

 making myself rather a nuisance to some of mv 

 friends — that a system of uniform colouring was not 

 the right one, whether applied to ships or to service 

 dress; that of all uniform colours the very worst, 

 whether by day or night, was the black which was 

 then still in use for destroyers, and so on. I also 

 kept on urging that the only way of obtaining really 

 satisfactory results was to' place the whole matter 

 o{ ship " camouflage " under the direction of one 

 "individual endowed with practical knowledge of the 

 sea and ships, artistic sense, and grasp of the scientific 

 principles involved. 



At last, during the summer of IQ17, I had the 

 satisfaction of seeing the principle of parti-colouring 

 come into its own. Discarded by the Admiraltv as 

 useless two years before, the value of the principle 

 was now recognised and its application entrusted to 

 skilled hands. Glaring defects which were at first 

 conspicuous were remedied, and the later efforts, such 

 as the great aeroplar.o-carrier, H.M.S. Argus, left little 

 opening for criticism. 



The importance of the subsidiary principle — that of 

 compensative shading — as an aid in " camouflage " 

 was, unfortunately, never fully grasped during the 

 course of the war. The distinguished expounder of 

 This principle, Mr. Abbott H. Thayer, was in the 

 strongest sympathy with the cause of the Allies, and 

 1 think it a great pity that it was not found possible 

 to enlist his practical help, which I feel sure would 

 have been gladly and freely given. 



It is only fair to state, in conclusion, that in my 

 personal communications upon this subject I laid 

 stress upon the use of parti-colouring as a means of 

 rendering ships less conspicuous. I also directed 

 attention to its use in confusing the details, especially 

 vertical lines, which are made use of by the enemy's 

 range-finders, but I did not lay sufficient emphasis on 

 this. Actual experience has shown that in submarine 

 warfare this second function — in particular, deter- 

 mination of the factor of relative movement — is of 

 overwhelming importance. But this does not affect the 

 main point I desire to make, namely, that the leading 

 principle underlying ship "camouflage" — the breaking- 

 up of the form of a vessel bv strongly contrasting 

 colours — is one familiar to biologists; that it was 

 made known to the Admiralty in the early days of 

 the war, although its carrving into practice was, un- 

 fortunately, bungled ; and that consequently newspaper 

 paragraphs which date the discovery of the principle, 

 instead of the more efficient application of it, from 

 the vear 1917 are distinctly misleading. 



J. Graham Kerr. 



University of Glasgow, Mav 6. 

 NO. 2585, VOL. 103] 



A Possible Case of Partial Sterilisation in Soil. 



When on active service in France in 19 18 I had, 

 partly as a hobby and partly for food supplies, a garden 

 on the site of an old brickyard. The land had been 

 waste land for certainly three years, and I believe 

 more. It received a light dressing of dung in February 

 and was dug up in that month; seeds were got in in 

 March. In April or May the land received by chance 

 a light top-dressing of a mixture of charcoal and brick- 

 earth impregnated with potassium carbonate and hexa- 

 methylene tetramine. The crops obtained were, in 

 my opinion, abnormally good, and much better than 

 those obtained by some French gardeners on cultivated 

 gardens near by. The chief crops grown were pota- 

 toes, dwarf peas, and dwarf beans ; the two last gave 

 the best results in the order named. It is not asserted 

 that the top-dressing brought about this result, as the 

 history of the soil is necessarily rather obscure; and 

 as it was not designed as a scientific experiment there 

 was no control plot, but it seems improbable that the 

 small amounts of nitrogen and potassium supplied by 

 it could have made the garden much better than 

 neighbouring ones. 



The suggestion is offered that the hexamethylene 

 tetramine may have liberated formaldehyde by the 

 action of dilute acids in the soil and caused partial 

 sterilisation. 



I have since subjected to steam distillation (a) a solu- 

 tion of hexamine, (b) untreated soil, garden soil, and 

 (c) garden soil moistened with hexamine solution. 

 Schiflf's reagent gave negative results in the case of 

 (a) and (b), but positive results with (c). 



F. Knowles. 



The .Midland Agricultural College, 

 Kingston, Derby. 



MINERAL PRODUCTION IN RELATION 

 TO THE PEACE TREATY. 



IT is gradually becoming more and more clear, 

 as the history of the Great War is further 

 examined, that one of the main objects of 

 Germany in attacking her neighbours was com- 

 mercial aggrandisement by destroying rival 

 manufactories and by appropriating the raw 

 material of industry wherever it lay conveniently 

 situated for that purpose, this raw material being 

 in the first instance all available mineral wealth. 

 She had already done this with supreme success 

 in 1871 ; the iron-ore fields of Lorraine then 

 wrested from France had formed one of the main- 

 stays of Germany's industrial development, and 

 she fully expected that the new war woiild yield 

 proportionately valuable results. This was 

 Germany's avowed policy; in the words of one 

 of the acknowledged German authorities, 

 Frederick Naumann, the object of a country 

 nowadays in going to war is purely "to benefit 

 the economic development of the country," and 

 German writers have ever since the commence- 

 ment of the war announced their fixed determina- 

 tion to retain in German possession the iron-ore 

 fields of French Lorraine, thus giving Germany 

 "the practical monopoly of iron-ore in Europe," 

 and assuring her of victory in the future wars to 

 which she was already looking forward. 



Until the actual boundaries, as roughly defined 

 in Sections II. and III. of the Peace Treaty, have 

 been accurately settled, it is only possible to form 



