handedness) so long as they were mixed or combined with inactive substances only, but M. Pasteur found that this is no longer the case when they are combined with active substances, as for example the organic alkaloids, in which case the salts obtained differ widely in solubility, crystalline form, &c.

It is to the stimulus afforded by the investigations of M. Pasteur that we must ascribe the more recent discovery by M. Marbach, that several crystals belonging to the cubical system possess the power of rotating the plane of polarization. Thus M. Pasteur's original discovery has already begun to bear fruit in discoveries made by others.

DR. SHARPEY, in the absence of the Foreign Secretary,

I request that you will transmit this Medal to M. Pasteur, in testimony of the value which we attach to his brilliant discovery.

Your Council have awarded one of the Royal Medals to Sir John Richardson. His claims to that honour as a most distinguished naturalist and scientific traveller, will I am sure be generally admitted. Sir J. Richardson's earliest work on Zoology appeared about the year 1823, but his first great work was published in 1829, namely the 'Fauna Boreali-Americana,' in which he has described the Quadrupeds and Fishes of the Arctic Regions, and with Mr. Swainson's aid, the Birds; the merits of this work, in the very accurate descriptions of the species, in the great amount of information on their habits and ranges, are admitted to be of the highest order. Since that period Sir J. Richardson has published largely on various branches of zoology, physical geography, and meteorology. His Reports to the British Association, on the Fishes of New Zealand and of China, are extremely interesting under many points of view. Another Report to the same body on the General Zoology of North America, is a most valuable contribution to science. His later works, which here must be more particularly considered, are the 'Zoology of the Voyages of the Terror and of the Herald,' in which he has described the Fishes and Reptiles collected during those expeditions, and given an account of some of the great extinct mammifers of the Arctic countries, with very interesting observations on their ancient relations and ranges. He has also lately contributed to the Geolo

gical Journal a valuable paper, in which he has made known the presence of tertiary strata abounding with vegetable remains, in districts now rendered sterile by the extreme cold. Altogether I think there can be no doubt that the merits of Sir John Richardson, as a philosophical naturalist, are of a very high order.

It is not within our province to reward his other claims to distinction; but all will rejoice, that in the conscientious discharge of a delicate and important duty, the Council have been able to bestow a Medal on one, who has earned the applause of all who have watched his career, for his patient endurance and fortitude under incredible hardships in his first Arctic Expedition in company with Franklin, and again for his chivalrous self-devotion in the cause of friendship and science combined, at a period of life when most men resolve to rest from their labours, or at least would hesitate to encounter the fatigues and dangers of a Polar Expedition, the anticipation of which must have been more appalling to one, who had bitter experience of their painful reality.

SIR J. RICHARDSON,

Accept this Medal as a token of our respect for your scientific labours and character.

The other Royal Medal has been awarded to Professor Thomson, whose labours in the cause of science are well known to scientific men. Yet the brief reference which can now be made to the Memoirs which he has written, will convey but an imperfect notion of the services which he has rendered; for the zeal with which he is inspired, his clear apprehension of mathematical and physical truths, and the freedom with which he communicates his ideas, have powerfully contributed to stimulate others in the pursuit of truth, and direct them into right paths. Shortly after graduating in the University of Cambridge he undertook the task of editing the Cambridge Mathematical Journal, which under his auspices was placed on an enlarged basis, under the title of the Cambridge and Dublin Mathematical Journal,' and is well known to the mathematicians of Europe. This Journal, as well as its predecessor the Cambridge Mathematical Journal,' is enriched by numerous contributions from the pen of Professor Thomson on various subjects, especially the mathematical theories

of heat, electricity, and magnetism. Among these may be mentioned a masterly article in which he has shown the compatibility of the ordinary mathematical theory of statical electricity with various phenomena which had been supposed by some to militate against it; his deduction from mathematical principles of Faraday's law relating to the motion of a small paramagnetic or diamagnetic body in a magnetic field; and his method of electrical images, first communicated to the public at the meeting of the British Association at Oxford in 1847, by which he is enabled in an extremely simple and elegant manner to solve a variety of important problems relating to the distribution of electricity on conductors.

Called to the Chair of Natural Philosophy in the University of Glasgow in the year 1846, he has ever since continued to devote himself to science in the intervals of his necessary occupations, and has worked especially at his favourite subjects of heat and electricity.

Carnot long since developed the mathematical theory of the motive power of heat in a clear and satisfactory manner, assuming as an axiom the indestructibility of heat. But the important researches of Mr. Joule have shown that this axiom must be abandoned, for that heat and work are mutually convertible. The establishment of this point necessitated a reconstruction of the mathematical theory of the motive power of heat, a theory of much practical importance from its direct bearing on the steam-engine, and this task Professor Thomson accomplished in a series of papers published in the Edinburgh Transactions.'

The

Professor Thomson and Mr. Joule have for a long time been working together, and they are now engaged in a series of experimental researches on the thermal effects of fluids in motion. expenses attending the prosecution of these researches have been defrayed by donations from the Government Grant, and the results already obtained, drawn up partly in the form of short provisional accounts, have appeared in the Philosophical Transactions' and in the Proceedings of the Royal Society.'

In connexion with this subject may be mentioned Professor Thomson's remarkable speculation as to the cause of the light and heat of the sun, which he refers to the impact of meteoric bodies circulating around that luminary and continually falling in. The

opinion of scientific men seems to be divided as to the reception of this theory; but whatever may be thought of its truth, it has at least the merit of referring the light and heat to known causes.

The mathematical theory of magnetism was developed by the illustrious Poisson, but was made to rest on foundations in some respects too speculative. This subject has been taken up by Professor Thomson, who in a lucid and satisfactory manner has placed the theory on the basis of observed facts, so as to render it independent of any ulterior suppositions which may be adopted respecting the nature of magnetism. Two papers on this subject are published in the Philosophical Transactions,' and others, containing the theory of magnetic induction, are promised. More recently Professor Thomson has published a series of papers devoted to the mathematical theory of the submarine telegraph, and has been engaged in a series of experimental researches relating to voltaic electricity, which formed the subject of the Bakerian Lecture delivered in the session just concluding, and of which the detailed account will shortly be in the hands of the Fellows of the Society.

PROFESSOR THOMSON,

Accept this Medal in testimony of our admiration of your able mathematical and physical researches.

Obituary Notices of deceased Fellows.

JAQUES CHARLES FRANÇOIS STURM was born at Geneva in September 1803, of a family which had quitted Strasbourg in the middle of the last century, where one of his ancestors had been President of the Republic at the period of its contests with the Emperor Charles V., and another had attained a distinguished reputation for his writings on jurisprudence and theology. After completing his school education and his classical studies at the College with remarkable success, he became in his fifteenth 8 year student of the University of his native city, where his rapid progress in the study of mathematics and philosophy attracted the marked attention of the well-known geometer Simon Lhuillier, who fully anticipated the eminence which he was afterwards destined to attain.

The sudden death of his father, leaving his mother and four children, of whom Charles was the eldest, without any adequate maintenance, compelled him, before the close of his seventeenth year, to resort to private tuition for the support of himself and his family; and three years afterwards he was recommended to the Duc de Broglie, as tutor to the brother of Madame de Broglie, the son of Madame de Stael. At the close of the year 1823, he accompanied his pupil to Paris, and though he shortly afterwards returned to Geneva, he found no sufficient occupation there, and he finally resolved, in company with his intimate friend and school-fellow, M. Colladon, the present distinguished Professor of Physics at Geneva, to seek his fortune in the great city, which was then, and had long been, the undisputed metropolis of European science. Sturm had already become very favourably known to mathematicians by several articles in the Annales de Mathématiques' of M. Gergonne, on different branches of analysis and geometry, and the strong recommendations which he and his companion bore with them from Lhuillier, and the kind offices of M. Gerono, made them known to Ampère, Fourier, Arago, and other eminent members of the Institute, who recommended them to pupils as a means of support. Sturm afterwards obtained employment upon the 'Bulletin Universel,' under Baron Férussac, and was, in fact, a subordinate in the office of that journal when he published his well-known Theorem. He and his friend speedily began to feel the influence of breathing in an atmosphere of science, and their joint labours were rewarded by a distinction of no ordinary importance, when the Academy of Sciences awarded to them the great prize of mathematics proposed for the best Essay on the Compression of Liquids.

The determination of the number of real roots of a numerical equation which are included between given limits, is a problem which had occupied the attention of the greatest analysts of the past age, of Waring, of La Grange, and more especially of Fourier, who of all other analysts had made the nearest approaches to its practical, though he had failed in its theoretical, solution: the attention of Sturm had been for some time directed to this class of researches, which he pursued with remarkable continuity and diligence, encouraged, as he himself assures us, by the instructions and advice of this eminent master. The result was the discovery of the theorem which

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