of his instructions was appreciated, and his enthusiasm also probably proved contagious. But as soon as he had in this way accumulated a little money, he dismissed his classes and shut himself up alone among his crucibles and alembics. Then, when his money was all spent, he again set to, to earn more in the same way; and, when he had done so, secluded himself as before. It was in the midst of all this, in November, 1837, that, to obtain from the University his degree of Doctor of Science (Docteur des Sciences), he presented his thesis on the Theory of Organic Combinations, in which he announced some of the most remarkable of his new views, and which he had to defend in a contest of two hours with Dumas and other professors.

We next find him employed for two years as superintendent of the chemical operations in the establishment of a Parisian perfumer. This he left to be chemist to a porcelain manufactory in Luxembourg. Here finding, on settling accounts with his employer after eighteen months, during which he had drawn no salary, except only a five frane piece now and then, that there was about 4007. sterling due to him, he thought himself rich enough to marry. And soon after he accepted a Professorship in the College of Bordeaux. But his late first experience of money-making, with the pressure of the new demands upon him in his altered condition, had now made him think that a larger income might be convenient; and he entered into partnership with another capitalist, no doubt much richer than himself, in a scheme for the manufacturing of sulphate of magnesia and sulphate of copper. It proved a failure, and, after a world of trouble, he was glad to get fairly disentangled from it at the cost of his ten thousand francs, all that he possessed in the world. "Take my all," he said, after they had wearied him out, “and let me off." He now, we are told, resolved to devote himself exclusively to the theoretical part of science, convinced that he had not a practical turn of mind.

The next thing we hear of him is his resignation of his professorship. No other reason is assigned for his taking this step, except that he found himself out of his element at Bordeaux, which he conceived to be essentially a literary town, and as such an uncongenial residence for a cultivator of the physical sciences. The true way of putting the case, perhaps, would rather be, that he felt his provincial life to be a sort of exile, or life underground, and yearned to get back to Paris, the centre of intelligence, as his proper home and working-place. Thither, accordingly, he repaired, in the beginning of 1846, with his wife and son, and a matter of 2,000 francs, being half his salary, with which they had paid him off, and established himself in a fourth floor of the Rue de l'Université, proposing to make an income by resuming his old plan of taking pupils. It was the same passion, though operating in an opposite direction with that which draws the wild man back to his woods, and

makes the heart of the Celtic mountaineer bound high when he feels his step once more upon the heather. There is some one kind of life that is alone truly life to each of us, in which alone we seem to ourselves to have the full light of day about us.

In an economical sense Laurent's transference of himself to Paris cannot be said to have turned out ill. He probably continued to make at least as good an income as he had had at Bordeaux; and he was certainly better placed for the prosecution of his peculiar studies and investigations, and also more in the way of public recognition and patronage. The laboratory of the Ecole Normale, we are told, was at once placed at his disposal by its director, M. Balard; and he was thus enabled to complete some important researches—although, it is intimated, in his modest and delicate feeling with regard to what was not his own, he confined himself to the use of such materials and apparatus as were least expensive.

Nor had he long to wait for a public appointment. In May, 1848, he was made Assayer to the Mint. He had thus again secured a fixed position. He now gave himself up entirely to the duties of his office and his chemical investigations, passing all his spare time at the Hôtel de la Monnaie, unfortunately in a room which is described as a kind of cellar, and both dark and damp. This soon began to tell upon his health.

We have collected the above facts from a somewhat more detailed account contained in the address of Colonel Philip Yorke, the President, delivered at the Anniversary Meeting of the Chemical Society of London, on the 30th of March, 1854, and published in the Quarterly Journal of the Society for July of the same year. Two years, Colonel Yorke states, passed in the circumstances that have been described. "Engaged,” the memoir proceeds, "on nearly all subjects of organic chemistry, and in analyzing the most complicated mixtures, Laurent yet found the means of extending his hospitality to one or two chemists who had no laboratories, and furnishing them with the means of working. His laboratory was the rendezvous of a great number of scientific men; there was no lack of news there; and Laurent had every day some new result to announce, or some new idea to develope. Raw materials were also sent to him from all sides for examination. Among other matters of this kind, mention is made of a certain amorphous precipitate, which no one was able to recognise, prepared by a chemist who refused to state the means by which he had obtained it, and moreover shrank from the difficulty of obtaining anything definite from it. Laurent was totally ignorant of its origin, but that made little difference to him. He employed his usual re-agents, and in a few hours succeeded in extracting from it a beautiful yellow crystalline substance consisting of a nitro-compound of the phenyl series. The amorphous pre

cipitate was a residue obtained by treating coal-tar naphtha with nitric acid.

"Laurent possessed a degree of analytical tact never before known : his researches on naphthalia, indigo, bitter almond oil, &c., remain as monuments of a genius for investigation which, unfortunately, will not soon be equalled. The immense number of new compounds which he discovered-for which, indeed, he was obliged to create a new nomenclature-were prepared with the aid of a small number of re-agents; and the merit of these researches is farther increased by the consideration that they were not merely the inspiration of an active mind, but were conceived under the influence of a fundamental idea, of which the Substitution Theory is one of the consequences. With chlorine, nitric acid, ammonia, sulphuric acid, and potash, Laurent produced his combinations and decompositions; water, alcohol, ether, and the goniometer, served him for the recognition and isolation of his products. He was the first to employ the goniometer as a re-agent, and no one knew better how to manage it. He had learned the use of it while pursuing his studies at the Ecole des Mines, and had early recognised its utility in purely chemical investigations. At an early period, also, he had laid down the fundamental proposition, that Form and Arrangement may be as important as composition—a proposition round which all his researches may be said to gravitate. The consequences which followed from it are well known: their names are, Theory of Nuclei, Theory of Substitution, Divisibility of Atoms, Paramorphism, Hemimorphism, Isotheromorphism, Multiple Equivalents, Law of Even Numbers, &c.

"In the midst of these brilliant discoveries, Laurent devoted himself to his work with daily increasing ardour, each laboratory session yielding its contingent of new results. As if aware of the premature end which awaited him, he used all his efforts to produce and to consolidate. Happily for science, but unfortunately for his family, this preoccupation of his mind bore sway over every other consideration, and made him totally negligent of the material side of life; as a pioneer of the future, he belonged especially to humanity, and devoted himself entirely to his mission as one who thoroughly appreciated it."

At length, however, an affection of the chest, under which he had been for some time suffering, became so much worse that his physicians insisted upon his withdrawing himself from his laboratory. He reluctantly obeyed; he consented to forego the more exciting work of actual analysis and experiment; but work of some kind was almost a necessity for his ardent nature and busy brain. Balard, Biot, and other friends suggested that he should weave the vast number of new facts that he had registered, and the various original views which he had from time to time thrown out, into a systematic treatise. He eagerly

caught at the idea; and in a comparatively short time he produced what Colonel Yorke characterises as a colossal work. "This work," the narrative goes on, "supplied him with constant occupation; as long as he was able to hold a pen, he worked at it with a degree of vigour and activity which excited the admiration of those who were acquainted with his situation. Laurent, indeed, had never deceived himself about the fate which awaited him; it was not the mere prospect of death which alarmed him, but he was about to leave a wife and two children in a state of destitution; he had had no time to amass wealth, nor had he rendered a sufficient amount of administrative service to hope for a pension for his widow. These harassing thoughts were not of a nature to ameliorate his already hopeless state; and those who approached his bedside during his intervals of delirium could well appreciate the poignant grief which oppressed the dying man.

“His delirium, however, was only occasional, and he retained his reason to the last moment. At times, indeed, he entertained hopes of improvement, and then began to think of resuming some investigation, verifying some fact, or examining some opinion: then, as throughout his life, ideas flowed rapidly in his brain; but he breathed painfully, and could not speak without the greatest difficulty. It might then be observed that he endeavoured to include the greatest possible meaning in the fewest words; but his sufferings increased, his respiration became more and more laborious, and he was even denied the consolation of making known his dying thoughts."

It seems to have been towards the end of 1853 that the struggling light was quenched, and the martyr to science released. Of the disposition and moral nature of the man we are told that he was kind, obliging, indulgent in his judgments of others, steady in friendship, firm in his convictions, a hater of injustice, always ready to acknowledge an error, but very sensitive, so that he suffered much from being or apprehending himself to be misconstrued, and fancied he had more enemies than he really had.. In a short life, he had yet done his work; and the torch had only burned the brighter for having wasted away so fast.

CHAPTER XXX.

DIVERSITIES OF INTELLECTUAL EXCELLENCE.

WEST.

PAINTERS:-BENJAMIN

THE ambition of intellectual excellence is the same passion, by whichsoever of the many roads that lie open to it it may choose to pursue its object. The thing that is interesting and valuable is the purity and

enduring strength of the passion. These are the qualities that make it both so inestimable in the possession and so instructive in the exhibition. The mere department of study in which it displays itself is of inferior importance; for, even if it should be contended that, of the various pursuits which equally demand the highest degree of intellectual application and devotion, one is yet better calculated than another to promote by its results the general improvement or happiness of mankind, it will scarcely be argued that even those of inferior value in this respect should not also have their followers. The arrangements of Providence, by forming men at first in different moulds, and placing them afterwards in different circumstances, regulate, doubtless with more wisdom and success than could be obtained by any artifice of human polity, the distribution of taste and talent and enterprise over the varied field of philosophy and art, no part of which is thus left altogether uncultivated. One man, from his original endowments, or his particular advantages of training or situation, is more fit for one line of exertion, another for another; and, although the pursuits to which they are in this manner severally attracted may not, in the largest view, be of equal importance, that is no reason why we should regret that there are labourers to engage in each. Indeed, the more truly enlightened any mind is, the less ready will it be to look with a feeling either of contempt or of slight respect upon any pursuit, which has had power to call forth in an eminent degree the resources of the human intellect. The ground is holy wherever genius has won its triumphs. The further the domain of science is explored, the more, in all probability, will it be found to be pervaded and connected, in all its parts, by a principle of order, consistency, and unity; and the more confirmations shall we discover of what are almost already universally admitted axioms of philosophy, that no truth is without its worth, and no sort of knowledge without some bearing upon every other.

We are now about to relate the history of some men of genius whose paths have been very different from those of the distinguished discoverers and inventors with whom we have last been engaged. But we shall find that, in every variety of intellectual enterprise, the same devotion and diligence have been exhibited by ardent and generous spirits; and that everywhere these qualities are the indispensable requisites for the attainment of excellence. By no class of students, perhaps, has a greater love of their chosen pursuit been displayed than by Painters, We have already had occasion, indeed, to mention many names from this department of biography, in illustration of the force with which a passion for knowledge has often contended against the most depressing discouragements, and eventually subdued everything that would have prevented its gratification. We have noticed the early difficulties and subsequent eminence of Salvator Rosa, Claude Lorraine, the Caravag