5: 



NA TURE 



[March 31, 1SS7 



and discus, the lumbricals of llie raanus are all supplied on 

 their superficial surface ; a similar arrangement is found m the 

 pes of the fox-bat ; here, however, the deep external plantar 

 also furnishes twigs to the two outer lumbricales. (4) It appears 

 probable from these facts that the lumbricals were all originally 

 supplied on their superficial surface : the deep nerve (ulnar in 

 hand, external plantar in foot) is, on this hypothesis, gradually 

 displacing the superficial (median ; internal plantar). This 

 invasion of the deep nerve has advanced further (in the case of 

 the lumbricals) in the human foot than in the hand. The reverse 

 is the case with the innervation of the short muscles of the 

 pollex and hallux. (5) There is a general correspondence 

 between the innervation of a particular lumbrical muscle and 

 that belly of the long perforating flexor of which it is a part ; 

 this fact is best made out in the case of the first or indicial lum- 

 brical of the hand and the indicial belly of the flexor perforans, 

 which are both supplied by the median ; it is also seen in the 

 fourth lumbrical and the belly of the long flexor ending in the 

 tendon to the little finger (both by ulnar) ; also in the third 

 lumbrical and annular belly (both of which have typically a 

 double nerve-supply). In the foot and leg this part of the 

 investigation presents special difficulties, which have, however, 

 in a measure been overcome by minute dissections of the pos- 

 terior tibial nerve and its branches, conducted under water. 

 (Dub/in University Reports.) 



ON CERTAIN MODERN DEVELOPMENTS OF 



GRAHAM'S IDEAS CONCERNING THE 



CONSTITUTION OF MATTERS 



I. 



"T^HERE is a certain fitness in our selecting this place to do 



honour to-night to the memory of Thomas Graham. For 



was in the chemical laboratory of this Institution that Graham 

 carried out, upwards of half a century ago, the experimental in- 

 vestigations which culminated in his memorable discovery of the 

 law connecting the rate of movement of a gas with its density. 

 This law, combined with that of Bjyle, which connects the 

 volume of a gas with its pressure, and with the law of Charles, 

 which expresses the relations of the volumes of gases to heat, 

 has done more to give precision to our knowledge of the consti- 

 tution of matter than all the speculations of twenty centuries of 

 schoolmen. 



Graham was made Professor of Chemistry in the Andersonian 

 Institution in 1S30, and it was from here that he gave to the world 

 his classical paper "On the Law of the Diffusion of Gases," 

 read before the Royal Society of Edinburgh, December ig, 1831. 

 I am fully conscious that my only claim to be regarded as worthy 

 to pronounce this eulogium of Graham arises from the circumstance 

 that I also have had the good fortune to hold the Lectureship of 

 Chemistry in this place ; and with forerunners like Birkbeck, 

 Gregory, and Graham, I may well be proud of an honourable and 

 distinguished ancestry. This association with the Andersonian 

 Institution naturally quickened my interest in Graham and his 

 works, and my frequent opportunities of conversation with the 

 late Dr. James Young, of Kelly, who for so many years was its 

 President, and who was, as we all know, also one of Graham's 

 discoveries, and for a long time, both here and in London, one 

 of his most trusted assistants, enabled me to learn much of 

 Graham's personal character and mode of work. On the occa- 

 sion of the gift of Brodie's fine statue of Graham to the city by 

 Dr. Young it fell to my lot to prepare the short biographical 

 notice of my distinguished predecessor, which, with other papers 

 relating to the matter, is, I understand, deposited in the archives 

 of your Corporation. And I may be pardoned, perhaps, for recall- 

 ing with what mingled feelings of pride and trepidation I set 

 myself to the execution of that task. 



In the preface to the admirable reprint of Graham's papers 

 which we also owe to the filial piety of Dr. Young, the late Dr. 

 Angus .Smith has indicated in precise and even luminous 

 language Graham's position in that chain of thinkers which in- 

 cludes Leucippus, Lucretius, Newton, and Dalton. Indeed, of 

 all Angus Smith's papers with which I am acquainte 1 there is 

 none, to my thinking, more charming than this little introductory 

 essay of a dozen octavo pages, in which, with unwonted perspi- 

 cacity, he has defined Graham's place in the history of speculative 

 philosophy. Angus Smith has here crystallised out, as it were, the 

 thoughts of a life-time of literary research and meditation. Pro- 



' The Triennial " Graham Lecture," given in the Hall of the .Andersonian 

 Instuution, Glasgow, on March 16, by Prjf, T. E. Thorpe, F. R S. 



bably, no man — certainly no contemporary of Graham's — was 

 better fitted by knowledge and by sympathy to form a sound 

 critical estimate of such a position than the biographer of John 

 Dalton. Angus Smith's mind was simply steeped in the old Hel- 

 lenic philosophy. To him even Kapila was more than a name, and 

 the atomic systems of India matters of more than conjecture or of 

 passing interest. There was much in Smith's intellectual nature 

 to make such inquiries congenial to him. With all his lean- 

 ing towards objective science he had a Highlander's love of the 

 mystical and a Lowlander's passion for metaphysics. .\nd yet 

 nothing is more admirable than the manner in which, in this 

 essay, these qualities and this wealth of learning are stibordinated 

 and held in check, and nothing more striking than the way in 

 which, in a few graphic strokes, done with a master hand, lightly 

 yet firmly, with a consciousness of power and a sense of restraint, 

 Graham's place in the evolution of the atomic philosophy is set 

 forth. 



It is here claimed for Graham that he was a true descendant 

 of the early Greeks, and that to him belonged as of right the 

 mantle of Leucippus. Atoms and eternal motion were as much 

 fixed articles of his creed as they were of that of Heraclitus. 

 But with no one of the older Greeks was Graham's thought more 

 in harmony than with that of Leucippus. He, with his wider 

 knowledge of the so-called " elemental " forms of matter, and of 

 the persistency with which the specific properties which we asso- 

 ciate with our " elements " are retained, could yet share witli the 

 old Greek his conceptions of the ess;ntial oneness of matter. It 

 was with Graham, as Smith says of Leucippus, that "the 

 action of the atom as one substance taking various forms by com- 

 binations unlimited, was enough to account for all the phenomena 

 of the world. By separation and union, with constant motion, 

 all things could be done." 



In one respect Graham's position as an atomist is unique : no 

 man before him had dedicated his life to the study of atoms and 

 atomic motion. These fundamental ideas are intertwined to make 

 up, so to say, the silver thread which runs through the work of forty 

 years. They were the dominant conceptions of his life. Even 

 in his earliest paper, published when he was just twenty-one, in 

 which he treats of the absorption of gases by liquids, we are able 

 to detect in the phraseology employed that his mind had been 

 already permeated by the notion of atomic movement. That he 

 should be familiar, even at this time, with the conception of atoms 

 in the Daltonian sense is hardly surprising when we remember 

 that he had already come under the influence of Thomas Thomson, 

 whose place in the history of science is probably that of the first 

 great exponent of Dalton's theory of chemical combination. 

 But the idea of motion was never with Dalton an integral 

 part of his theory, nor, in so far as it was necessary as serving 

 to explain the phenomena of chemical union, was it held by 

 Thomson. And this is the more remarkable when we remember 

 that Dalton had discovered for himself the fact of the molecular 

 mobility of a gas, and that his first glimpses of the truth of his 

 great law were obtained by the study of chemical combination 

 among gases. Graham was doubtless cognisant, in a general way, 

 of the speculations of the early Greeks, but there is no evidence 

 in any of his writings, nor has anything been preserved in the 

 reminiscences of his friends and contemporaries, to indicate that 

 he was knowingly influenced by them. 



This continuity of idea is indeed the most striking character- 

 istic of Graham's labours ; all his work seemed to centralise 

 round this fundamental conception of atomic motion. "In all 

 his work," says Smith, " we find him steadily thinking on the 

 ultimate composition of bodies ; he searches after it in following 

 the molecules of gases when diffusing ; these he watches as they 

 flow into a vacuum or into other gases, and observes carefully as 

 they pass through tubes, noting the effect of weight and of com- 

 position upon them in transpiration. He follows them as they 

 enter into liquids and pass out, and as they are absorbed or dis- 

 solved by colloid bodies, such as caoutchouc : he attentively 

 inquires if they are absorbed by mefals in a similar manner, and 

 finds the remotest analogies, which, by their boldness, compel 

 one to stop reading and to think if they be really possible. He 

 follows gases at last into metallic combination, and the lightest 

 of them all he makes into a compound with one of the heavier 

 metals, chasing it finally through various lurking-places until he 

 brings it into an alloy and the form of a medal, and puts upon it 

 the stamp of the Mint. Indeed he is scarcely satisfied even with 

 this, and he finds in bodies from stellar places — in meteoric iron 

 — this same metallic hydrogenium which he draws out from its 

 long prison in the form of a gas. . . If we examine his work on 

 Salts and on Solutions we have a similar train of thought. One 



