138 



NA TURE 



[December 12, 1901 



vessels extending a short distance from its periphery. In many 

 animals the optic disc is deeply excavated up to its margins, and 

 resembles that of chronic glaucoma in the human subject, a 

 state of which the best examples are furnished by the seal, llie 

 serval, and the red and white flying-squirrel. The condition 

 presenteil by the rabbit, in which some of the fibres of the optic 

 nerve carry their sheaths through the lainina cribrosa to form an 

 opaque patch on the retina, is met with in many other animals, 

 but with much variety in the depth and distribution of the 

 opacity. 



The coloration of the tapetum varies greatly in different 

 animals ; and Dr. Johnson calls particular attention to his draw- 

 ing of the eye of Monteiro's galago, in which the general yellow 

 of the central part of the fundus is surrounded by a zone of 

 pigmentation precisely resembling what is called " pigmentary 

 retinitis " in the human subject. Dr. Johnson inclines to the 

 belief that the affection so described is not really a disease, 

 but rather a reversion to a type of structure which is the rule 

 in night-seeing animals. 



It is impossible to withhold a tribute of admiration from the 

 perseverance with which Dr. Johnson has conducted his 

 researches, or from the beauty of the drawings in which the 

 results of his observations are displayed ; but it is for the 

 moment necessary to retain a suspended judgment with regard 

 to the value of his work. As an observer he stands alone ; and 

 the drawings which he has made, notwithstanding their great 

 and obvious merit, are as yet mere personal records, liable, it 

 may be, to some disturbing influence from a personal equation. 

 It is much to be regretted that photography has not been made 

 available for taking pictures of the eyeground from which this 

 element of uncertainty would be removed. Even if this were 

 done, it would still be necessary to determine, by more extended 

 portraiture, whether the conditions described are normal ones 

 or subject to variation in individuals. We cordially welcome 

 Dr. Johnson as a pioneer, and we feel sure that he will fully 

 appreciate the necessity for caution in accepting his conclusions. 



THE COAL-TAR COLOUR INDUSTRY IN 

 GERMANY AND ENGLAND. 

 V\riTII the object of ascertaining our present and future 

 * prospects in the chemical trade of the world, Mr. A. G. 

 Green, in a paper read before the section of chemistry of the 

 British Association, at this year's meeting, described the relative 

 progress of the coal-tar industry in England and Germany 

 during the past fifteen years. The council decided to print the 

 paper in cxlenso, and the subjoined particulars extr.acted from it 

 convey an idea of what England has lost by the neglect of the 

 scientific foundations of an industry. The paper may be 

 regarded as a sequel to one by Prof. Meldola published in 

 Nature fifteen years ago (vol. xxxiv. p. 324), when the position 

 of the industry in Germany and England was described, and a 

 warning was given to British manufacturers. 



The exports of coal-tar colours manufactured in England 

 have fallen from 530,000/. in 1890 to 366,500/. in 1S99. Com- 

 paring these figures with the rapidly increasing export trade of 

 Germany, it is seen that whereas formerly the English evport 

 trade in artificial colours was about one-quarter that of Germany, 

 it does not now amount to a tenth part. It is therefore only 

 too apparent that we have had but little share in the great in- 

 crease which this industry has experienced during the past fifteen 

 years, and that we have not even been able to supply the ex- 

 pansion in our own recpiirements. In order to ascertain what 

 proportion of our own needs we at present furnish, I am able to 

 lay before you the following interesting figures, which have been 

 kiiidly supplied me by the Bradford Dyers' Association and the 

 British Cotton and Wool Dyers' Association, who together form 

 a very large proportion of the entire dyeing trade : — 



Colouring Matters used by Bradford Dyers' Association. 

 English, 10 per cent. ; German, So per cent. ; Swiss, 6 per 

 cent. ; French, 4 per cent. 



Colouring Matters used by British Cotton and IVool Dyers' 

 Association. 



Aniline Colours. — English, 22 per cent. ; foreign, 78 per 

 cent. 



Alizarine Colours. — English, I "65 per cent. ; foreign, 9835 

 per cent. 



NO. 1676, VOL. 65] 



The English Sewing Cotton Company have also very kindly 

 supplied m-; with a detailed analysis of their consumption, from 

 which it appears that out of a toial of sixty tons of colouring 

 matters and other dyeing materials derived from coal tar, only 

 9 per cent, were of English manufacture. 



The following table of statistics of the six largest German 

 funis gives a fair picture of the present dimensions of the industry 

 in that country {vide next page). 



The joint capital of these six firms amounts to at least 2^ 

 millions. They employ together about 500 chemists, 350 

 engineers and other technologists, 1360 business managers, 

 clerks, travellers, \c., and more than iS,ooo workpeople. 

 Compared with such figures as these the English colour 

 nianufacture assumes insignificant proportions. The total capital 

 invested in the coal-tar colour trade in England probably does 

 not exceed 500,000/, the total number of chemists employed 

 cannot be more than thirty or forty, and the number of work- 

 men engaged in the manufacture does not amount to more than 

 a thousand. 



A similar relative proportion is maintained in the number of 

 patents for new colouring matters and other coal-tar products 

 taken by the English and German firms, as is shown by the 

 following table : — 



Comparison of Number oj Completed English Patents for Coal- 

 tar Products taken during 1886-1900 by six largest English 

 and six largest German Firms. 



German Firms. 



Badische Aniline Works 179 



Meister, Lucius, & Briining 231 



Farbenfabriken Bayer & Co. 306 



Berlin Aniline Co 119 



L. Cassella & Co 75 



Farbwerk Miihlheim, Leonhardt & Co 38 



Total of SIX German firms 948 



Englisli Firms. 



Brooke, Simpson, and Spiller 7 



Clayton Aniline Co 21 



Levinstein 19 



Read, Holliday, & Co 28 



Glaus & Ree 9 



W. G. Thompson 2 



Total of six English firms 86 



Nor does the potential loss which we have sustained by our 

 inability to take advantage of a growing industry represent the 

 sum total of our losses. The new colouring matters, made 

 almost exclusively in Germany, have in many cases been intro- 

 duced as substitutes for natural products, which were staple 

 articles of English commerce. Madder and cochineal have 

 been replaced by alizarine and azo-scarlets, the employment of 

 many dyewoods has greatly decreased, whilst at the present 

 moment logwood and indigo are seriously threatened. Regard- 

 ing the indigo question so much has been written that I do not 

 propose to occupy space in its further di.scussion, but will only 

 point out that the complete capture of the indigo market by the 

 synthetic product, which would mean a loss to our Indian 

 dependencies of 3,000,000/ a year, is regarded by the Badische 

 Company as so absolutely cert.ain that, having alre.idy invested 

 nearly a million pounds in the enterprise, they are at present 

 is,suing 750,000/ of new debenture capital to provide funds to 

 extend their plant for this purpose ! In the last annual report 

 of the company they say : "As regards plant indigo, the direc- 

 tors are prepared and determined to meet this competition in 

 all its possible variations in value. Much strange matter has 

 been published in India as to improvements in the cultivation 

 and preparation of natural indigo, but the illusions of the planters 

 and indigo dealers are destined to be dispelled before facts, 

 which, although they are not known to them, will make them- 

 selves more felt the larger the production of artificial indigo 

 becomes." 



Besides the loss of material wealth which the neglect of the 

 coal-tar trade has involved to the country, there is yet another 

 aspect of the question which is even of more importance than 

 the commercial one. There can be no ijuestion that the growth 

 in Germany of a highly scientific industry of large and far-reach- 

 ing proportions has had an enormous effect in encouraging and 

 stimulating scientific culture and scientific research in all 



