dj: 



NA TURE 



[April 7, 1892 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of i^^Tvnv., 

 No notice is taken of anonymous communications. ] 



Ornithology of the Sandwich Isles. 

 It is easy to make assertions which, however improbable, it 

 is not easy to disprove. I would therefore invite Mr. Albert F. 

 Calvert to furnish documentary evidence of those he has ad- 

 vanced {supra, p. 485). They do not indeed materially affect what 

 I had said ; yet, for the sake of accuracy, it might be as well to 

 know on what foundation they rest. Those who are interested 

 in the growth of ideas will be pleased to find that Sir Joseph 

 Banks was so far in advance of his time as, on his return from 

 his voyage with Captain Cook, which ended in 1771, to have 

 "several cases of birds carefully mounted and arranged ac- 

 cording to the localities in which they were collected " ; and, 

 among them, a "group of land birds from Owhyhee " — an 

 island which Cook did not discover until 1778 — or seven years 

 later. As these assertions alone concern the subject on which 

 I wrote, I refrain at present from offering any remarks on the 

 others ; but your correspondent seems to have been the victim of 

 a delusion or something worse. Alfred Newton. 



I OBSERVE in Nature (p. 485) a letter from Mr. Albert F. 

 Calvert, in which he states that certain cases of birds, which 

 were collected by Sir Joseph Banks during his voyage in the 

 Endeavour with Captain Cook, "were in the custody of the 

 Linnean Society of London until 1863, when they formed part 

 of their natural history sale." 



This is not the fact. The birds belonging to Sir Joseph 

 Banks were never in the possession of this Society. It is true 

 that the Society at one time possessed the insects and shells 

 which formed part of the Banksian collections, and these in 

 1863 were presented, not sold, to the Trustees of the British 

 Museum. Had there been any birds, they would doubtless 

 also have been presented at the same time. 



Where, then, did the cases, which Mr. Albert F. Calvert says 

 are still "carefully preserved in the museum of his ancestor 

 Mr. John Calvert," come from ? Certainly not from the Linnean 

 Society. In view of Prof. Newton's valuable communication 

 to Nature (March 17, pp. 465-69), it is of importance that this 

 inquiry should be answered, and a list furnished of the species 

 contained in these cases, the reported existence of which will 

 agreeably surprise ornithologists. 



As Mr. A. F. Calvert has disclosed a source of information 

 likely to be useful, perhaps he may be able to answer another 

 question. 



In i860 the late Mr. J. D. Salmon, a well-known oologist, 

 bequeathed to the Linnean Society a valuable collection of birds' 

 figgs. This collection was known to contain the eggs of many 

 British birds which were then becoming scarce, and have since 

 become still rarer, if not quite extinct as breeding species ; 

 such, for example, as the golden eagle, osprey, kite, buzzard, 

 honey buzzard, raven, chough, dotterel ; and amongst some of 

 the rarer species not found breeding in Great Britain, the spotted 

 eagle, gerfalcon, black kite, rough-legged buzzard, Lapp owl, 

 &c., and, above all, an egg of the great auk {Alca impennis), the 

 value of which alone would almost equal that of all the other 

 eggs in the collection. 



I am informed that on the death of Mr. Salmon this collec- 

 tion was intrusted by his executors, 'for the purpose of being 

 catalogued, to someone known to Mr. A. F. Calvert's ancestor ; 

 and by some accident, when it came to be handed over to the 

 Linnean Society, the egg of the great auk was (some time after- 

 wards) found to be missing, as also the eggs of certain species 

 above mentioned, with several others that might be named. 



Possibly they may have been removed at the time for safe 

 custody, and were forgotten to be returned when the collection 

 was deposited in its present resting-place. 



Perhaps Mr. A. F. Calvert will say whether by chance these 

 eggs (like the Banksian birds) have been "carefully preserved in 

 the museum of his ancestor." If so, I presume that, on proof of 

 the bequest of the collection to the Linnean Society, and proper 

 identification of the eggs by their nu-nbers, initials, or other 



NO. 1171, VOL. 45] 



marks, Mr. A. F. Calvert would be willing (on behalf of his 

 ancestor) to restore them to the cabinet from which they have 

 been so long missing. J. E. Harting. 



Linnean Society, Burlington House, March 28. 



Poincare's Thermodynamics. 



It is clear that I was justified in attributing the gist of M. 

 Poincare's first letter to his not having sufficiently read my 

 notice of his book. He has not even yet fully apprehended 

 the bearings of that notice, as a few words will show. Far 

 from being unable to uphold any one of my critical remarks, as 

 M. Poincare is pleased to hint may be the case, I reassert every 

 one of them, and could easily add to their number. 



Let us begin with the particular item of my criticism which 

 M. Poincare persists in regarding as the most important. My 

 words were: — "in his assumed capacity [of pure analyst] he 

 quite naturally looks with indifference, if not with absolute 

 contempt, on the work of the lowly experimenter." As an 

 illustration of this I instanced M. Poincare's ignoration of the 

 thermo-electric researches of Sir W. Thomson, Magnus, &c. 

 Then I quoted (in full) two of his reuiarks on the "Thomson 

 effect. " In the first of these he used the very peculiar phrase 



" Sir W. Thomson admet qu'il existe une force &c.": — 

 and in the second he said 



" si I'effet Thomson a pu etre mis en evidence par I'experience, 

 on n'a pu jusqu'ici constater V existence des forces electromotrices 

 qui lui donnent naissance." 



To these he has, in his recent letters, added other like state- 

 ments. Now, as I understand the matter, Lord Kelvin proved 

 (which, as I take it, means a good deal more than might be 

 implied by "constater ") the existence of the electromotive force 

 which depends on the so-called "Thomson effect" (giving 

 also thereby the means of measuring its amount) by showing ' 

 that the Peltier electromotive force does not in general fully 

 account for the observed current in a thermo-electric circuit, 

 and may even be directly opposed to it ; while no other source 

 of electromotive force can exist save the gradation of tempera- 

 ture in one or both of the metals. He then proceeded, by 

 experiment, to measure the amount of the " Thomson effect " 

 for unit current in various metals, unequally heated. When 

 the passages above quoted from M. Poincare's work are com- 

 pared with the facts just stated, my comments on them will be 

 seen to be fully justified. 



It is necessary to add that I made no reference whatever to M. 

 Poincare's distinctions between "true" and "apparent" 

 electromotive force : — simply because I regard these, along 

 with many other celebratea terms such as " disgregation " &c., 

 as mere empty names employed to conceal our present 

 ignorance. 



As to the three chief objections I made to the work of M. 

 Poincare, every one (author, critic, or onlooker) is entitled to 

 form and express his opinion. I need not restate mine, though 

 I continue to adhere to every word of it : — but I may make the 

 following additional remarks on these objections severally. 



1. What sort of title to completeness can be claimed for a 

 Treatise, on Thermodynamics, in which no mention is made of 

 the grand principle of Dissipation of Energy ; nor of Thermo- 

 dynamic Motivity, "that possession the waste of which is called 

 Dissipation " "i 



2. With regard to the measurement of Absolute Tempera- 

 ture, what I did say was that the experiments of Joule and 

 Thomson, which justified them in basing it on Carnot's Func- 

 tion, were not mentioned by M. Poincare in this connection. 

 The omission by M. Poincare of the italicized words makes an 

 absolutely vital change in the meaning of my statement ; and 

 enables him to make what, (at first sight only), appears to be an 

 answer to it. 



3. As regards the foundation of the Second Law, it is 

 unfortunately clear that M. Poincare and I must continue to 

 differ : — so that further discussion of this point would be un- 

 profitable. For I presume that M. Poincare has not formed his 

 opinion without careful study of all that Clerk-Maxwell said on 

 the point : — so that even a perusal of Lord Kelvin's latest paper 

 {Fortnightly Revieiv, March 1892) is not likely to induce him 

 to change it. P. G. T. 



26/3/92. 



M. Poincare and Maxwell. 

 In his recent treatise on " Electricite et Optique," M. Poincare 

 professes to give a description of Maxwell's theories of electro- 



