note the age of the limb, . . . their density depends on the dryness of their natal seasons:" also "the heart of a tree will be found nearer to its southern bark than to its northern." Fossil shells and fish likewise engaged his attention, and indeed, so numerous were his studies in Natural Science, that it would be tedious to make mention of them further than as an illustration of the character of his investigations. The invention of the Planisphere is also claimed for him, drawings of which are among his MSS. at Windsor. That Leonardo anticipated Cordan in believing that the phenomena of the camera tended to explain the laws of vision, is obvious from his own words-"This spiracle made in a window. . . conveys within all similitudes of the bodies opposed to it. Thus may we see that the eye likewise acts." His remarks on Optics are full of suggestive insight, coupled with skillful investigations. He constructed an eye of glass by which to illustrate his conclusions; and then gave himself up to considerations and inventions "concerning the means for making the moon appear larger by the use of lenses."* He also wrote a treatise on "Force as a cause of Fire." We may gather from these suggestive items some idea of the character of his studies, carried on in the intervals of his artistic pursuits. In being brought face to face with nature and with science in those methods of study which form the right training of the artist, it is impossible that the mind should not feel some stimulus towards strictly scientific investigation. It must be a dull mind which excludes inquiry into subjects bordering upon its special pursuits; experience teaches that these very pursuits are the better mastered through this breadth of culti vation which we find illustrated in the best masters in science or art.

But to continue our subject. It was not until long after Perspective had been discovered and applied in art, by Paolo Uccello, and the brothers Van Eyck, that science formulated it. Science was forestalled by art in two distant countries at the

It must be remembered that this anticipates Galileo by nearly a century. Vasari records of Leonardo that in his youth he first suggested the formation of a canal from Pisa to Florence, by means of certain changes to be effected in the river Arno. Bottari says in a note: "This magnificent work was executed about 200 years after, by Vincenzio Viviani, a disciple of Galileo."

same time, in Italy and in Belgium. Before the time of Giotto, through the long period of Byzantine art, it had remained unknown. But in Giotto and his followers we find evidence that not mere "personal observation and artistic cleverness enable them to seize this necessary ingredient of pictorial art," but that it was reduced to principles, formed into precepts, and taught to scholars. Pietro della Francesca deserves especial notice in this connection; he died in 1482. There is evidence in his works that he not only understood and practiced Perspective with great accuracy, as Vasari records of him, but he reduced its principles to writing in three books, which are still in existence. Before the literature of perspective commences, Raphael, in his "School of Athens," and Michael Angelo, in the ceiling of the Sistine Chapel, had shown themselves consummate in the application of Perspective to art. Then "the anticipations of art were verified by science and reduced to unvarying rule." It was not till 1608 that the first satisfactory treatise on this subject was published by Guido Ubaldo. In 1642 the Prospectiva Practica, commonly known as the Jesuits' perspective, appeared-very generally in use among artists. until quite recently. Finally the correct mathematical theory of perspective was propounded by Brook Taylor in 1731. Copies of these works are before us.

A mathematical basis, consisting of proportion, relation, and quantity, underlies all art, in line, color, form, and pictorial composition, no less than in musical harmonies. Michael Angelo claimed that the human figure is perfect in its proportions and these proportions have a definite law. The thought was not original with him, but was derived from the ancients. "The human form is bounded by lines, the angles of which are all harmonic, and the curves which circumscribe the subdivisions possess this quality in no less degree."

Before considering Architecture in relation to points of contact between science and art, a mere glance at the Sculptor's work will show us the scientific requirements of his art. The character and function of every muscle of the human form is to be mastered; of every bone which affects the outward appearance or gives support to the parts. He is to possess accurate knowledge of every action of which this form is capa

ble, of the scope and function of every bone and muscle, and under all imaginable action, such as cannot be studied from the living subject; instance of which we have cited in the Laocoön. But all this, in the most accurate form of scientific knowledge, will not effect for art those still higher requirements which are as yet beyond the reach of science, and in respect of which knowledge is extremely limited. The gulf between the genius of our being and what we know of its nature and scope is still vast and unfathomed by science.

In respect to these "points of contact," Architecture presents numerous illustrations; for Architecture naturally divides into two branches-the artistic and the constructive, or scientific. "On the one side it seems to descend toward the class of mechanical pursuits; on the other, it has in the past laid contribution on its two sister arts, and commanded their highest resources."

The

In its artistic phase, which is subservient to the expression of certain effects, line, form, space, and color are the elements with which these effects in Architecture are produced. It is perfectly tonic, in respect to its lines, angles, and curves. Parthenon has been reduced to a strict mathematical proportion in its construction, and the harmony of the parts have been found to fulfill a certain mathematical ratio. Said Penrose, "Its calculated and measured dimensions do not vary, even within the fraction of an inch." The same treatment has been applied to Lincoln, and later to Salisbury Cathedral, and it has been ascertained that their proportions have this same character and are reducible to similar principles. Though the men who built those great edifices "may have had no idea of the science which they obeyed, they had it in the education of their feeling and judgment; when science came in and tested their work she merely verified and found it strictly according to its rules."

But in its constructive branch, Architecture is almost exclusively scientific; with respect to the nature and selection of materials; in all its constructive forms in carrying out the conception or design. "The early builders could not calculate the proportion requisite between superincumbent weight and its just support; and they erred on the right side, by providing superabundant strength to carry their intended burden." We

observe how, "by degrees, every architecture becomes slimmer and lighter, as experience has brought these proportions to test;" hence, after the Doric comes the Ionic, then we get the Corinthian, and at last the Composite. In like manner we pass from the Norman, through intermediate stages of pointed architecture, to the Flamboyant or Decorated. Remarkable evidence remains, that the heavier construction of remoter periods "was not based upon any accurate calculation of ratio between support and weight." The first went beyond the demands of the second. We find the architects of the sixteenth century, "fearlessly altering the old Norman arches into the pointed, and round massive piers into slender clustered columns; thus cutting out masses of sustaining material without apprehension of insecurity."

As in the departments of science there are multiplied subdivisions, and human labor in these fields is now directed into specialities, so are like subdivisions the characteristic of modern art, which is divided and subdivided, the artist applying himself exclusively to some one art, and again to some one branch of this, to portraiture, to landscape, to history, to genre. Architecture is subdivided into church architecture, public buildings, domestic architecture, exclusively of shops and dwellings. Bridge-building has been wholly turned over to the engineers. The architect, so-called, does little more now than get out the plans and elevations. But it is characteristic of a thorough mastery of any art not to submit to this narrowing specialism, not to neglect the science for the superficial attractions, but to treat the whole with that sympathy and thoughtful insight which a knowledge of the structure and functions of the human form demands, from the most evanescent expression that lingers upon the features, down to the very bones of the skeleton.

Before closing our remarks on this topic, let us glance at a few of the later results of applied science mechanically contributing to the interests of art. Stone columns, once laboriously shaped and polished by hand, are now turned and glossed by machinery, at much less cost. Stone is dressed by the same means. Stone itself is manufactured and molded into various forms and ornaments. The tendency of this is un

artistic in its effect, because what is done by machinery lacks that expression which manual labor, directed by individual mind and feeling, gives to the material it shapes.

This could be remedied if, after the forms were shaped by mechanical means, the final execution were reserved for direct human contact, giving character and expression to the forms; very slight superficial labor would serve to give this final finish. The sculptor gives his clay model to his workman, who delivers to him the marble reproduction drawn from the block by pointing measurements; but the sculptor goes over it with the instinct associated with its earliest conception, giving the subtleties of expression, texture, accident, and grace of execu tion which, with very little additional labor, gives value and interest to the work. Why could not we, in the place of insipid, machine-made columns and ornaments now generally in use, have exact repetitions of such charming examples as may be found abroad in old buildings, churches, cloisters, etc., copied mechanically by means of plaster cast taken from the originals, and finished by hand, making the laborer's work more free, thoughtful, and stimulating to his own fancy.

Iron, in the uses to which it is applied in the architecture of the day, is altogether a recent result of applied science, but as now used it is an abomination so far as artistic expression is concerned. Plaster casts taken from Gothic or Rennaissance ornament might be sent to the foundries to be used as patterns. Much wood-carving is now done by machinery. We have seen the head of a dog carved in wood by this means, which had the character of hand-work. Such carving as may be found in Belgium and Perugia might be reproduced by this means, ad infinitum.

Science, in its applications, has brought that chief of musical instruments, the Piano, within the reach of every household. Every separate feature of its construction, from its general form to the material which enters into the manufacture of its finest wires, has been subjected to scientific tests and investigations. The interpretation of the masters of musical composition may now be heard on the extreme borders of civilization, in the log-cabin as well as in the households of the wealthy. But Musical-boxes, such as are now imported from Switzerland, have