He did not mean that geniuses differ essentially in their quality; the nature of genius, whether mathematical or strategic, or literary, is constant and invariable. So calcium carbonate can crystallize either in rhombohedral or hexagonal systems; but its chemical nature is the same in both cases. Explosions, unconsciousness, novelty, intermittence, are common to all forms of genius. But, Mr. Sergi says, their having a common nature does not at all explain why they differ from each other. So the fact that both forms of crystallized calcium carbonate belong to the same chemical substance, does not explain why two forms exist. Water and ice have the same molecular and atomic composition of hydrogen and oxygen, but only a special physical condition of temperature makes them assume the appearance of water or ice.

Now, how can we explain the great variety of geniuses? Why does an artistic genius, an historical, an archælogical, exist? This is a new problem, and heredity is not sufficient to solve it.

Sometimes surrounding influences, with predisposition and hereditary transmission, determine the form that genius shall take. So Darwin, St. Hilaire, Raphael, Bach, and the Bernoullis, were born of naturalists, painters, and mathematicians, and lived among them, finding in atavistic tendency and surrounding intellectual atmosphere the first cause of their later work. But this is not a general rule; on the contrary, geniuses, particularly the scientific, show a tendency to-I might say-dissimilar heredity, by means of which sons are as different as possible from their parents. Edgar Allan Poe was a descendant of rigid Puritans.

Sometimes the environment alone and at large, particularly economic and social conditions, causes geniuses to follow their definite bent. Many a great jurist has lived in Italy, where crimes. and litigations are very frequent, and warlike Piedmont has been the cradle of many a famous warrior. Among the Hebrews, who were and are great merchants, students of economics are numerous: recall, for example, C. Marx, Ricardo, A. Loria, L. Luzzati. The instance of Ricardo is peculiar; he had no inheritance of genius from his father, nor was he inspired by him; he simply shared in his father's business and speculations, and from commercial practice he drew economic applications, which are generally inspired by a very practical spirit, owing to his previous work and his rise subsequent to great commercial events, such as the monetary crisis of 1809.

But all these facts must be considered with much circumspection, because often it has been the very lack of favorable circum

stances that has excited manifestations of genius and caused them to spring forth. Without misery and misfortune we should not now have the novels of George Sand and Harriet Beecher Stowe and the comedies of Goldoni. The history of genius is full of circumstances apparently opposed to its development. Boileau, Le Sage, Descartes, Racine, La Fontaine, Goldoni, were obliged to hide their muse beneath the grave garb of the lawyer and the theologian. Poisson's parents wanted him to become a surgeon; Herschel's and Cellini's meant to make players out of them. Michaelangelo's father wanted his boy to become an archæologist; never -he used to say-an image-scribbler. When a great sculptor saw the lad's first attempt and begged to have him placed in his own studio, Michaelangelo's father exacted of the sculptor a yearly sum for this privilege.

Flaubert was in his childhood intended for a lawyer.

Galileo had among his ancestors, up to 1538, several philosophers, magistrates, and great thinkers (cf. V. Nelli's "Life of Galileo," 1793). Even his father, Vincent, was an original musician and a student of geometry; his brother Benedict was also a praiseworthy musician. But evidently his heredity had no direct influence on Galileo; nor had his education, because education in those times inclined strongly to rhetoric and classicism-Nelli affirms that there was then only one school of mathematics and geometry in Tuscany, nor could his medical studies have been of any use to him, because medicine was quite theoretic and without the foundation of experiment.

It appears, then, from the above instances, that hereditary and surrounding conditions, once the causes most commonly assigned, either fail to explain the origin of genius-variation, or are contradictory or insufficient. Nor, to determine the special temper of a genius, is it enough to know the domination of acoustic or visual centers, the vivacity of fancy, the rapidity of synthesis that we discover so easily in his handwriting and style, although such conditions of intelligence have an enormous influence on genius. But a visual genius may become a poet, sculptor, painter, histologist, or calculator; and an acoustic genius may be a musician, or an orator, a poet, or critic, or novelist. This domination is not sufficient to settle the variety of genius. So I believe that there is another factor of utmost importance to which belongs the principal part in this determination, and with which heredity, environment, and the peculiar nature of genius are co-operators: that is, according to my opinion-a strong impression received at puberty.

GENIUS AT PUBERTY.

He who analyzes biographies of great men will find that in most cases the determining cause of creative direction lies in the combination of individual tendencies, with a very strong sensorial impression made at a time not far from puberty.

While a mere lad, Segantini's genius for painting had already flashed upon the walls of the Reformatory where he was kept, and where his superiors wanted to make of him, willy-nilly, a shoemaker. Had they encouraged and rewarded him, he would, possibly, have been an able shoemaker, of whom nobody but his customers would have known; but they abused him; then he fled from his wicked protectors to his native mountains, where he became a shepherd. There he used to draw sheep and huts without any particular thought of it. Once he was twelve years old then-he saw a little girl die, and her mother disfigure herself painfully, because she could not preserve her daughter's image. He was inspired, and made a picture of the child: from that day he was the great Segantini. The combination of strong moral and physical impressions, at the very beginning of puberty, with such a powerful visual talent, made him a genius as a painter.

Proudhon was the son of a wood-cutter; the curé of his parish had taught him a little Latin, and the Benedictine friars of Cluny the elements of drawing. At the age of fourteen, he was trying to copy some bad pictures in that convent, with colors made out of plant juices and brushes of mule hair, when a friar told him that he would never succeed with his strange methods, because those pictures were oil-painted. Such a remark was sufficient to make him find out the secrets of oil-painting by himself, as Pascal did those of geometry. (Gauthiers, 1136.)

Stuart Mill, at the age of twelve, was so deeply affected by studying his father's "History of India," that his genius and passion for historical and economic events began at that time.

Arago, a lawyer's son, was precocious in music, and took an interest, while a youth, in classical studies. His passion for mathematics burst forth suddenly when an artillery officer told him that he had rapidly reached his position by graduating from the Polytechnic School and studying exact sciences. Then Arago quitted Corneille for mathematics; he studied them by himself, and at the age of sixteen was ready to take the examination for the Polytechnic.

Thomas Young was so precocious that at the age of two he

could read, and at five he had learned a large number of English and Latin poets, whose works he could recite by heart. When eight years old, he once met a land-surveyor, who showed him his instruments to calculate distances and the elevation of far-away bodies; he immediately set himself to study a dictionary of mathematics, to understand the structure of those instruments. He made a microscope by himself, and learned differential calculus in order to comprehend mechanics. (Arago-Euvres completes, 1854, Volume II.)

Galileo, up to his seventeenth year, made no physical discovery of any consequence; he felt himself inclined to exact sciences and detested the inexactness of metaphysics and medicine. But when at eighteen, in his third year of medical training, he saw in the Cathedral at Pisa a lamp regularly oscillating, he thought suddenly that he could invent an instrument for the purpose of studying the laws of isochronism, and examine the state of the pulse.

Lioy, in Martini's "Primo Passo," says that he was eight years old, when, at the birth of a little brother, he was shut up in the library to keep him quiet, so that he should not disturb his mother, and a volume of Buffon was given him to read. It was the spark for his genius. "It seems to me as if I saw those birds yet; I dreamed of them all the night long; my place as a coming naturalist was settled."

Darwin, at eight, while he had already a great passion for collecting plants and animals, fancied, or rather, invented, and told to a schoolmate, the story that he could change the hue of flowers by sprinkling plants with colored solutions. It was a mere story, but it shows that from those early years he had observed the variability of plants. The germ of that idea, which was to dominate his whole life, was concealed in this puerile fiction that afterward became a reality. The great English naturalist believed that his having seen at that time a copy of a journey around the world, which greatly interested him, caused him to long for trips to far countries, and to travel, in later days, on the Beagle. On the contrary-he says-school, as a means of education, was simply a cipher to him. (Vie et correspondence de Ch. Darwin, 1888, p. 32.)

Poisson (Arago-Œuvres, V. III.) was to be, according to his parents' wish, a phlebotomist; his education was entrusted to an uncle of his who pretended to instruct him by making him puncture the veins of cabbage leaves with his lancet; he was always making mistakes. But at eight or nine, he once saw a programme

of the Polytechnical School and noticed that he could readily solve. some of its problems: his career was discovered and his future settled.

La Fontaine was the son of an official, a poor verse scribbler. His genius was revealed when his attention was attracted to Malherbe's beautiful poem on Henry IV's death. Then he knew that he could be a poet, and such he was.

Gianni (Universal Biography) became a poet when first he read Ariosto. Then he made extempore verses, before he had learned the art of composition, shortly after puberty.

Lagrange had no great aptitude for study; his mathematical genius appeared when, as a high school student, he read one of Halle's writings; he wrote then his first essay on the calculus of

variations.

Benjamin Franklin was the son of a mechanic. At eleven, he had to leave school, and, to earn his living, entered a soap factory, and later a printing house where he could learn something. Having noticed for the first time the discharge of an electric spark in a toy machine, he imagined that lightning had the same origin, and discovered the theory of lightning and the lightning-conductor.

In all these cases, sensation did not rouse genius, but was the occasion of its revelation, and determined an individual who was organically predisposed, to turn to an end from which circumstances, education, etc., tended to take him and to separate him. permanently.

So Darwin was predisposed by atavism to great naturalistic synthesis, because several of his ancestors had already worked in that direction, and his wit gave precocious proof of such predisposition in his idea of getting artificially colored plants. But, according to his own declaration, all the education he received was of no help to his later studies. The voyage of the Beagle was the point of departure for all his creations, and the intense wish for that came to him from reading, at puberty, a book on a trip around the world (Correspondence, 1878).

Sir William Herschel was a player who had learned by himself languages and mathematics, without any special end in view. His aving seen, at twenty-one, the field of the sky through a telescope, struck him so forcibly that he made a telescope himself, and was driven to study which metal alloy was the best reflector of light. The result was, that by the age of thirty-six he had achieved the construction of a great new telescope.

Lalande, a pupil of the Jesuits, composed dramas and novels at