SCIENCE. 



203 



or cats, the Satanos of Col den and the Shawanons of later 

 writers were one and the same people. These several tribes 

 were then followed with the minutest care, so far as the early 

 writers throw any light upon the subject. The latter part 

 of the paper was a detailed account of the wars, treaties and 

 fortunes of this people from 1755 to the present day. The 

 discussion upon Mr. Royce's communication was partici- 

 ticipated in by Colonel Garrick Malleiy and Major J. W. 

 Powell. 



Hr. Hough's paper related to the influence of the inheri- 

 tance of knowledge and character as making progress in 

 civilization possible. Each individual and each race is the 

 outcome of all those material and psychical causes which 

 have co-operated to bring them into existence. These facts 

 were used by the author to show that the civilization of our 

 race cannot be forced upon another race. By a multitude 

 of examples Mr. Hough illustrated the methods by which 

 the causes which give rise to races and phases of culture 

 are brought together and co-operate to their end. The 

 paper was discussed by Mr. Lester F. Ward, Major J. W. 

 Powell, Professor O. T. Mason and Colonel Garrick Mal- 

 lery. 



4*» 



THE PRIORITY OF THE LATE FRIEDRICH 

 MOHR IN REGARD TO THE PRINCIPLE OF 

 THE CONSERVATION OF ENERGY. 

 By Dr. Geo. W. Rachel. 



In an interesting essay entitled, " On the History of 

 Forces," published by Dr. C. K. Akin in the Philosophical 

 Magazine} occurs the following passage : 



" There has been of late a good deal of controversy re- 

 garding the priority of invention or discovery of this last 

 named principle [Correlation of Forces] and it may be inter- 

 esting, in a historical point of view, to take cognizance of 

 passages of much earlier date than hitherto relied upon as 

 establishing such priority, and upon which I have in the 

 majority of cases rather accidentally lighted." 



The controversy alluded to by Dr. Akin in the passage 

 quoted, may be said to have continually attracted the atten- 

 tion of scientists since the above reference was made to 

 it sixteen years ago. It is well known that Tyndall's 

 authoritative statement of Dr. Robert Julius Mayer's 

 priority has been accepted almost universally since it first 

 appeared. 



And yet there always was a number of scientific men 

 who held another opinion; but in spite of their protests, even 

 to-day the authority of Tyndall prevails, and the popular 

 notion all over the civilized world is that Mayer first dis- 

 covered and proclaimed the great principle in question. 

 This view, however, is erroneous, and in this paper the writer 

 intends to prove, by the introduction of documentary evi- 

 dence, that the late Prof. Fr. Mohr, of Bonn, was the first 

 ■who, in clear and unmistakable language, proclaimed the prin- 

 ciple of the ''correlation of forces " and the " mechanical theory 

 of heat " on which it is based. 



The history of the essay, on which his claim of priority in 

 this matter rests, is a peculiar one, and since the circum- 

 stances attending its loss and its re-discovery have had a 

 direct bearing on the controversy in question, they are 

 worth mentioning. 



It is certainly a unique occurrence, that a scientist should, 

 for a period of thirty years, have been absolutely unaware 

 of the fact that an article which for the first time in the his- 

 torv of science states a principle of the utmost importance, 

 had actually been published in one of the scientific periodi- 

 cals to which he sent his MS ; and this was due only to the 

 failure, on the part of the publisher or the editor, to transmit 

 a copy of the number containing the paper to the author. 

 But this is what really happened in the case of Prof. 

 Mohr's article " On the Nature of Heat." 



1 Phil. Mag., 4 th series., vol. XXVIII., No. 191, December, 1864 ; pp. 

 470-477. 



Mohr first sent it to Poggendorff, but the latter declined 

 its publication for the peculiar reason that " it did not contain 

 any new experimental researches." 11 It was therefore returned 



to Mohr and by him, in turn, sent to Prof. Baumgartner, 

 at Vienna, who, at that time (1837), in conjunction with Dr. 

 Von Holger, published and edited his Zeitschrift fiir Phy- 

 sik und Verwandte Wissenschaften. Not being informed by 

 these gentlemen what had been done with the paper, he 

 supposed it to have been shelved by them on grounds 

 similar to those which prompted Poggendorff's refusal. 

 It was only by an accidental reference to this essay in one 

 of his later works 3 that he chanced to hear of it again. 



Dr. Akin wrote to him that it had been published by 

 Baumgartner and von Holger, in the fifth volume of their 

 Zeitschrift, etc., p. 419, a passage of it having been quoted 

 by him [Dr. A.] in the essay refered to above. 



The files of this magazine — which had a very limited 

 circulation — having become scarce, since, shortly after 

 its publication had ceased, the publishing firm was 

 dissolved, it was very difficult to procure a complete 

 set. Thus it was that Mohr had to wait many months un- 

 til, in response to a request, he received a copy of the 

 volume in question, sent for temporary use only by the 

 librarian of the Vienna Polytechnic School, Prof. Hlasiwetz. 

 A letter, accompanying it, contained the following pas- 

 sage : 



" .... I am happy to be able to congratulate you 

 on this important essay, which puts your priority in regara 

 to the question of the mechanical theory of heat beyond any 

 doubt. I am glad furthermore that I should have been instru- 

 mental in the re-discovery of this hidden treasure 4 . . . ." 



Very soon after Dr. Adolph Barth, of Leipzig, the pres- 

 ent editor of Poggendorff s Annalen, succeeded in hunting 

 up a full set of files of the Zeitschrift, etc., and presented 

 them to Prof. Mohr. 



Since then the paper in question has been twice re-pub- 

 lished in full. The first time by the author himself in one 

 of his later works, with an explanatory statement, contain- 

 ing the history of its loss and re-discovery as given above, 5 

 and again by Dr. Hermann Klein in the seventh volume 

 of his scientific monthly, the "Gael" in the year 1871. 



Although Mohr has never pressed his claim to priority, 

 it is certainly due to his memory that all the facts in con- 

 nection with it should become fully known. It is always 

 to be regretted, when personal considerations — not to say 

 animosities — come into play in such questions ; but it seems 

 as if this very matter had been destined to be the sub- 

 ject of an unceasing feud which has at times even taken 

 the shape of a personal quarrel. Only a few years ago 

 Prof. Duhring was ' dismissed ' from Berlin University by 

 a vote of the faculty, because he had accused Prof. Helm- 



2 For the same reason it was that the editor of the great A nnalen de- 

 clined five years later the publication of Dr. Mayer's paper on the same 

 subject, and it therefore appeared in Liebig's Annalen der Cheviie 

 (42, 240.) 



3 Mechanische Theorie der chemischen Affinitat, Fr. Vieweg ; 

 Braunschweig, 1868. 



4 The letter bears date of Oct. 17, 1868, so that the author received and 

 first saw the article fully thirty-one years after its publication. 



5 Allgemeine Theorie der Bewcgung und Kraft, etc. Fr. Vieweg, 

 Braunschweig, i860, pp. 80-106. 



Note. — It is to Mohr, and the fate of this essay, that Dr. Akin refers 

 in a passage contained in his latest letter to Prof. Stokes, which was 

 published in No. i,of " Science." On page 170 of this Journal he says : 

 " Another [Mohr] who started similar ideas about the same time, having 

 been repulsed in one quarter (Pogg. Ann.) took it for granted that the 

 same had happened to him also in another (B. & v. H. Ztschr.f. Phys., 

 &c.) where it was not the case, so hopeless did he consider his endeavor 

 to obtain a hearing." 



It is a strange coincidence that the same humiliating experience was 

 reserved for the last months of the great man's life. For, the last three 

 essays which he wrote, each one of them, abounding in new and original 

 ideas, were also declined by the editors of " Liehig's Annalen." This 

 unwarrantable procedure so disgusted the family of the venerable philoso- 

 pher that they decided after his demise not to publish them in Germany 

 at all. They have honored the writer by intrusting to him the publica- 

 tion of these valuable essays, and the readers of ' Science" will soon 

 have opportunity to judge, for themselves, of the new and striking views 

 advanced by this great thinker. 



