January 3, 1901] 



NA TURE 



2^1 



full account of this work will appear shortly in the Astrophysical 

 Journal. 



Any observers planning to use a Nicol prism in connection 

 with a spectroscope in the manner described will find a gas or 

 candle flame illuminated with a beam of sun-light, concentrated 

 by means of a large mirror or lens, extremely useful in making 

 preliminary experiments. 



For work on the polarisation of the corona, I believe that the 

 artificial corona, which will be described next week, will be found 

 most useful for preparatory work. Not only is it polarised, and 

 polarised in the same wayas the real corona, but it resembles it in 

 every respect, and can be easily made of the same brilliancy. It 

 would be well to work with particles of different size, giving 

 diff"erent percentages of polarisation, and the picturesque refine- 

 ments for producing the polar streamers could, of course, be 

 omitted. A lamp with a ground glass globe might be used to 

 advantage, giving a distribution of polarisation more nearly like 

 that of the actual corona. 



Data regarding the plane of polarisation in the streamers 

 would be useful in formulating a theory of the streamers. 

 These, it seems to me, can be conceived as formed in two ways : 

 they may be streams of coronal particles moving in curved 

 paths, in which case the plane of polarisation should be every- 

 where strictly radial, or, what is extremely improbable, they 

 may be caused by divergent beams of light coming from the 

 polar regions of the sun and moving in curved paths owing to 

 the rapid decrease in the refractive index of the sun's atmosphere 

 in an outward direction. If this were the case, the plane of 

 polarisation would turn with the streamer. This latter hypo- 

 thesis is extremely visionary, and I do not present it seriously, 

 for it is almost impossible to conceive of any way in which the 

 isolated beams of light could be formed, unless, perhaps, by 

 vortex funnels more highly luminous than the surrounding sur- 

 face of the sun. Such fanciful speculations are hardly worth 

 indulging in, though they have interested me for the moment in 

 connection with the matter of possible curvature of light rays in 

 the sun's atmosphere, alluded to in a recent paper by Julius in 

 the Astrophysical Journal. R. W. Wood. 



University of Wisconsin. 



The Alleged Decadence of German Chemistry. 



As a man of business, more or less interested in the course of 

 chemical discovery in so far as it affects chemical products of 

 market value, I have for so many years been accustomed to take 

 note of the rapid strides made by Germany in the chemical 

 industries, that the statement contained in the article by 

 " W. J. P." in your issue of December 27 (p. 214) has struck 

 me with amazement. The writer says that "all students of 

 contemporary chemical literature will agree that in Germany the 

 science of chemistry has been in rapid decadence during recent 

 years." This statement seems to me so completely at variance 

 with my own experience that I have consulted chemical 

 friends as to its accuracy, and I cannot find any chemist who 

 agrees with this verdict. The consensus of opinion is, in fact, 

 all in the opposite direction. " W. J- P-" himself admits, as a 

 generally recognised principle, that supremacy in any particular 

 industry goes hand in hand with supremacy in the related 

 sciences. Every one of the discoveries recorded in his own 

 paper has been made in Germany, and he himself points out 

 that the new industry is "almost wholly of German origin." 

 Of course, as an English merchant, I hold no brief for German 

 products, but having long ago recognised the importance of 

 the connection between science and industry, which the author 

 emphasises, and seeing what Germany has been doing of late 

 years, I perhaps innocently attributed the progress of that 

 country to their superior system of training in chemistry and 

 related sciences, and to the readiness of their manufacturers to 

 avail themselves of the results of scientific discovery. For the 

 sake of British industry, I shall be only too glad to learn that I 

 was mistaken ; but since no chemist of my acquaintance agrees 

 with the writer, and since he himself puts forward a whole body 

 of German discoveries in order to tell us that chemical science 

 is undergoing " rapid decadence" in that country, I cannot but 

 feel that there is such a glaring contradiction between the facts 

 recorded and the conclusions arrived at by the writer that 

 some further e;jwplanation as to his meaning is necessary, 



S. N. C. 



V Secondary Sexual Characters. 



Mr. Pocock (p. 157) has replied to my letter, but he has- 

 not replied to my reasoning. It is no reply to say that it may 

 be doubted whether my hypothesis is an improvement on certain 

 others, when no reasons are given for the doubt. It is no 

 argument to say that a problem is insufficiently supported by 

 evidence, and may be true or false. A problem may be solved, 

 but it cannot be either true or false, nor can it be supported' 

 by evidence. Mr. Pocock himself in his article attributed the 

 colour of the male nilghaie and other antelopes to "male 

 katabolism," which he now says is nothing but an imposing, 

 substitute for the " vital force" of the pseudo-scientific realists. 

 I quite agree with him, and only hope that in future he will 

 not explain male peculiarities by attributing them to male 

 katabolism. 



It is very difficult to reason with a naturalist who uses the 

 terms "struggle for existence" and " influence of external con- 

 ditions " as equivalent to "selection." I quite understand that 

 to the Darwinian the only important action of external con- 

 ditions is the selective action, the survival of the fittest. But 

 the Darwinian does not appear to understand his opponents'^ 

 conception of the modifying non-selective action of external 

 conditions. Mr. Pocock does not distinguish between variations 

 and modification. If any cause acts on all the males of a species 

 and makes their colours dark or black, what effect can selection 

 produce ? If the dark colour is harmful, the species will become 

 reduced or extinct. But selection cannot, as Mr. Pocock 

 suggests, "check" a general modification due to a general 

 cause without eliminating the species. 



Thus the question which Mr. Pocock raised in his original 

 article, and which he now "sets aside," the question of the 

 initial cause of sexual modifications, is the essential question of 

 the whole subject, and cannot be set aside in any rational dis- 

 cussion of the facts. Even supposing that the variations are 

 different and not general, and that those which are beneficial 

 are selected and preserved, selection offers no explanation of 

 the fact that in so many cases the peculiarities in question are 

 inherited only by the male sex. Mr. Pocock, in discussing the 

 uses of coloration and markings, was obliged to refer to cases 

 in which the males differed from the females both in colour 

 and in horns. He has not yet realised the truth that no 

 theories based on the conception of selection afford any 

 explanation of unisexual inheritance. 



Penzance, December 17, 1900. J. T. Cunningham. 



The Word Physiography. 



With reference to the question of the early use of the word- 

 Physiography to express the comprehensive study of Nature, to 

 which you refer on p. 207 of your last issue, I should like to 

 call attention to a fact which appears to have been almost 

 forgotten. 



The title-page of a " Dictionnaire des Termes usites dans les 

 Sciences naturelles," published in Paris in 1834, bears as a 

 motto the words — 



" Profecto physiographiam qui colit, ullo pacto metam per- 

 fectioris cognitionis felicius non attinget, quam si aliquot dies 

 terminis perdiscendis tribuerit." — LinnL 



I have tried, but without success, to find this quotation in the 

 works of Linnaeus ; perhaps some of your readers may be able 

 to supply the reference. The word Physiography was certainly 

 current in Sweden about the middle of the eighteeenth century, 

 as in the obituary notice of Torbern Bergman, read at the 

 Stockholm Academy of Sciences in 1786 (which I know only 

 in the German translation), it is mentioned that he became a 

 member " der Physiographischen Gesellschaft in Lund, 1776." 

 "Minerva "for 1900 — 1901, however, states that the Physio- 

 graphical Society of Lund, which still exists, was founded in 

 1778 for the study of the scientific and economic conditions of 

 the province of Scania. There was at the same time a Cosmo- 

 graphic Society in Upsala, and the two names seem to have 

 been used much in the same sense. 



I think it possible that the word Physiography was introduced 

 in Sweden by Linnseus as a substitute for Cosmography, the 

 ancestor alike of the Physiography of South Kensington, and. 

 the Physical Geography of the older text-books. 



Hugh Robert Mill. 



NO. 1627, VOL. 63] 



