Dec. 17, 1874] 



NATURE 



129 



No doubt the Roy.il Agricultural Society was not founded for 

 the advancement of science in general or of botany in particular. 

 When, however, it transcends the practical limits it has imposed 

 upon itself, and promotes a purely scientific investigation, the 

 way it sets about it is, I suppose, a fair object of criticism in a 

 scientific journal. 



Mr. Jenkins complains that I have not taken the trouble to 

 read the official reports published by the Society, and thinks my 

 criticisms upon them might have had some value. As a matter 

 of fact I have done so, and my diiificulty is to be quite sure that 

 I understand what the last and most important really means. 

 To say nothing of the occurrence of " jonidia " for "conidia," 

 I find tlie following sentence : — " Prof, de Bary expresses 

 sangiune hopes that he has at last discovered the certain nids 

 [sic) or resting-places of the oospores or active primary genns of 

 the fungus." It would not have occurred to me to describe 

 oospores — in other words, resting-spores — as active, and it has 

 been suggested to me as not impossible that oospore may also 

 be a misprint in place of zoospore. There is the more necessity 

 for caution in the matter, as the publications of the Royal 

 Agricultural Society do not seem to receive the botanical re- 

 vision that might have been expected. Only last year^and it 

 was not a solitary blunder— a fungus was figured in the Society's 

 Journal as Aspergillum (sic), which was obviously no Asper- 

 gillus at all, but the common Bread-mould (As^ophora Muccdo). 

 No doubt, in due course, we shall have the opportunity ot 

 reading, at full length, what Prof, de Bary has added to our 

 knowledge of the matter ; but in the meantime we should not 

 forget what is due to those who have already worked at the sub- 

 ject in this country. 



Mr. Jenkins denies that the Society offered prizes for disease- 

 proof potatoes. I find that in the report of the judges on the 

 abortive essay competition, presented to the Council, Dec. 10, 

 1873, it was recommended, "That valuable prizes be offered 

 for {a) The best disease-proof early potato ; [b) The best disease- 

 proof late potato." Again, the recently published official report 

 to which I have already referred commences : " The judges 

 appointed to inspect the growth of the six varieties of potatoes, 

 7i'hich "i'cfc entcrtd for competition as disease-proof" &c. It may 

 be that this is " colloquial ' ' language, and does not mean what it 

 says ; but Mr. Jenkins must know that if by any chance any one 

 of the potatoes tried had run the gauntlet of the three years' 

 trial, it would have been advertised far and wide as stamped with 

 a "disease-proof" character by the Royal Agricultural Society. 



Mr. Jenkins complains that I suggest an offensive spirit as 

 actuating the Society in its communications with Prof, de Bary. 

 I can only say that I used the Society's own language. I 

 find that the judges, in their report, after decliniiii; \o recom- 

 mend any one of the ninety-four essayists for a prize, propose 

 "That a sum of money (say 100/.) be granted /d- t/ie purpose of 

 ;«i/«a'«n" a competent mycologist to undertake the investigation 

 of the life-history of the potato-fungus " (as if nothing had been 

 done in it already). The joint Botanical and Journal Committee 

 thereupon gave notice that they would ask for a grant of 100/. 

 to carry out this recommendation. I am not aware that the 

 British Association proceeds in this w.ay in distributing its funds, 

 and I leave Mr. Jenkins to reconcUe what I have quoted with 

 his statement, " that the frst step taken by the Council of the 

 Society was to direct me to write to Prof, de Bary." 



Let me sum up the substance of my criticisms. The potato 

 disease has been before the scientific world for thirty years, and 

 has been investigated by Berkeley in England, Montague and 

 others in France, De Baiy in Germany. The Royal Agricultural 

 .Society takes charge of a competition which induces ninety-four 

 persons to write on a subject on which it was a priori in the last 

 degree improbable that they could have any really important 

 unpublished facts to bring forward within the limits of even the 

 extended time at which the essays were to be sent in. On the 

 failure of this scheme prizes are offered for disease-proof potatoes, 

 "disease-proof " being subsequently defined to mean immunity 

 from disease in twenty different districts for three years. Were 

 a disease-proof potato a probable thing, it might clearly be 

 trusted to establish its own reputation. Lastly, the amateur 

 world of prize essayists having proved fruitless, the cryptogamic 

 botanists of this country — many of them men of Europtan fame, 

 who would doubtless have willingly responded to an appeal 

 from the Council to co-operate in the matter — are passed over 

 en bloc, and the matter is placed in the hands of a German 

 scientific man — highly and worthily distinguished, doubtless — 

 but who, I am convinced, would be far from approving the 

 slight placed on our countrymen, one of whom has accomplisheil 



what will ever be a classical research in this very subject. I 

 submit that when I applied the expressions "spasmodic " "ill- 

 considered," and "wanting in scientific method" to these pro- 

 ceedings, I was not using inappropriate language. 



W. T. Thiselton Dyer 



Sensitive Flames 



Permit me to thank Prof. Herschel for his all too kind 

 acknowledgment of the aid my former brief communicalien to 

 Nature may have been to him. In a paper on Sensitive 

 Flames that is awaiting the needful leisure to complete, I have 

 given a brief history of this subject — which, by the way, so far 

 as regards the discovery of sensitive flames, Prof. Herschel has 

 partly misapprehended, though there can be no doubt the valu- 

 able letters of Prof. Herschel will play an important part in the 

 development of these phenomena. I am glad to find that, so 

 far as Prof. Herscliel has recorded his views, they corroborate 

 the results of my own experiments (begmi as long ago as 1867) 

 in search of the cause of the sensitiveness of various fluid jets, 

 and the application of sensitive flames to acoustic investigation 

 and other practical ends. For reasons, into which I wiil not 

 enter here, I was led to postpone this inquiry, and it is only 

 comparatively lately that it has been resumed. 



The keynote to the whole of the phenomena is, I believe, to 

 be found in Savart's beautiful investigations on liquid jets. Any 

 fluid body, gaseous as well as liquid, escaping from an orifice in 

 a tranquil stream, consists of a continuous and a discontinuous 

 region, and is subject to the play of opposing forces which excite 

 pulsations in the jet, the number of which is directly proportional 

 to the velocity of the issuing stream, and inversely as the dia- 

 meter of the orifice. When a note is sounded approximately in 

 unison with the vibration number of these pulsations, the jet of 

 water, smoke, or flame is thrown into more vigorous vibration, 

 and a strained condition of the jet is set up. 



Hence it is easy to obtain a series of sensitive flames, issuing 

 from orifices of decreasing size, capable of respondmg (within 

 a certain range) to the successive notes of the gamut ; the higher 

 notes affecting, of course, those flames from the smaller orifices, 

 and which also require to be under greater pressure of gas than 

 the flames responding to the lower notes. The relative rate of 

 vibration of these flames is at once clearly seen by viewing them 

 together in a moving mirror. But I will not weary your readers 

 by further entering upon a subject with which already they must 

 be somewhat tired. W. F. Barrett 



Royal College of Science, Dublin, Nov. 30 



Fossils in " Trap " 

 I AM much obliged by your insertion of my letter on " Fossils 

 in Trap." You are right in supposing that the trap I refen-ed 

 to was crystalline augitic trap. If it had been tufa I should not 

 have written to you as I did, as I was well aware that fossils in 

 tufa were of common occurrence. Shortly after I wrote I 

 found that the I^'azmitcs £ot/i/andica which shows the section is 

 still imbedded in a portion of the slate, which is olive-coloured, 

 and closely resembling the trap. This is so intimately connected 

 with the trap that it is impossible to trace a /i:ie of connection. 

 Halifax, Nova Scotia, Nov. 14 D. Honeyman 



[Dr. Honeyman's discovery would appear to resolve itself 

 into the simple fact that his "trap-dyke" has involved in its 

 mass fragments of the fossiliferous strata through which the 

 molten rock has risen — a fact, we presume, with which every 

 practical geologist who has worked amongst igneous rocks must 

 be more or less familiar. — Ed.] 



THE RELATION OF RACE TO SPECIES 



IN a notice of Ouetelet's works, published in Nature, 

 vol. V. p. 358, I raised the question whether this 

 eminent statistician's method of detining a race or popu- 

 lation might be applied to provide naturalists with a 

 means of defining species. Since then, the consideration 

 of ISIr. Francis Gallon's explanatory diagram, given at 

 p. 28 of his woik on " Hereditary Genius," has led me to 

 attempt to carry this problem a stage further. 



Instead of using, with Quetelet, a binomial curve to 

 show the constitution of a race, with its central type and 

 varieties, Mr. Galton sets before our minds the very indi- 



