solar spots. He considers the action of Jupiter in this matter to be established; and as we are now in the epoch of minimum spots, he asks whether we can recognize any influence analogous to that which M. Alexis Perrey, of Dijon, attributes to the moon over the volcanic eruptions of our planet. He thinks it probable, considering the immense mass of Jupiter, that he may cause an accumulation of solar atmosphere at the equator, augment its density and absorbing power, and thus lessen the rapid cooling actions which ordinarily take place in that zone. He likewise suggests that planetary attraction may collect some of the cosmical matter of the zodiacal light in the plane of the sun's equator, and thus mitigate both radiation and evaporation. M. Chacornac considers that the line of research followed by Messrs. Warren De la Rue, Balfour Stewart, and Loewy, is calculated to settle these questions.

In a note M. Chacornac says that since the text of his paper was written, other observations make him believe "that a central body may be clothed with an incandescent ocean, and that penumbra are craters of elevation." Our present object is not to criticise, but simply to give an account of the most generally interesting portions of M. Chacornac's important publication.

PHOTOGRAPHY AS A FINE ART.

THOSE Who considered that the function of the artist was merely to copy natural objects with accuracy and fidelity, were (though erroneously) prepared to be satisfied with the operations of photography as soon as they were conducted with a sufficient amount of technical skill. There are certain cases in which art realizes all the conditions of deceptive imitation, and it is not very difficult to paint a butterfly, or a deal shaving so that a spectator might actually expect to be able to catch the pretended insect, or pick up the thin curly slice of wood.

When this mechanical fidelity is realized, there are many persons who conceive that nothing more is to be desired, and they form in their own minds a rude and inaccurate mode of estimating pictures according to the amount of realism which they exhibit.

A little more acquaintance with the facts of nature and the possibilities of art soon lead to the conclusion that realistic imitation is only possible to a very limited extent, and that in the main what may be called the imitative part of the artist's work consists in transposing, according to natural laws, the

facts of nature into the technical language of art. The painter can make no real imitation of the light which streams from the sun or the artificial fire, and his scale of light, shade, and colour is not only much lower, but in many respects different from that of nature. Only to a slight extent and under favourable circumstances can he, with any success, make the slightest attempt to imitate the strength of white light as seen in nature, and the art of the colourist is shown in his power of transposing what nature has composed in keys of actual light into corresponding, but not resembling, keys, such as his pigments enable him to provide.

The eye, as a living organism, does not remain in one and the same condition during any considerable portion of time in which an object is contemplated. Thus, if an object consists of parts in different planes, rapid focussing changes will occur in the eye, and the impression of vision is not the simple result of any one of these focussings, but a sort of average resulting from all. The perception of colour is not a simple affair. According to original sensitiveness and cultivation, the sensation of a colour is followed by another sensation of its complementary hue, and when two or more colours are simultaneously presented to the eye, very slight differences in the direction of that organ, and in the attention which the mind pays to its indications determine the precise result that is produced. The brightness of natural objects seen in full lights not being imitable by the artist, it follows that his productions cannot have the same power of summoning up complementary tints. Again, natural objects are more or less in motion, and more or less affected by motions of light and shade upon them, and the artist has to select and stereotype one out of many successive appearances presented to his view.

But it

A few considerations of this kind will show how soon the limits of realistic imitation are reached, and it must also be remembered that even if accurate imitation were possible, it would not satisfy the human mind, which demands imagination, sentiment, emotion, as well as beauty in works of art. is generally supposed that photography comes to us with something like a perfection of imitative capacity. This is not the case. Instead of photography being necessarily right, imitatively considered, it is necessarily wrong. In the first place its focussing is a compromise, and if we take one of the best specimens of photographic landscape, its treatment of foreground, middle distance, background and greater distance, will never be found conformable either to nature, or to the impressions which, through the eye, the scene depicted makes upon the mind. In nature yellow light is the next in point of brightness to white light. Photographic machinery turns it into black.

The natural scale of brightness as connected with colour is constantly at war with the photographic scale; and the results of this conflict are seen in all photographic works which attempt to give a black and white version of a polychromatic object or scene.

The rise amongst us of the pre-Raphaelite school, and the modifications which that school, as represented by its leading artists, has undergone, has familiarized most minds with questions pertaining to detail or generalization. To paint a number of leaves and branches correctly, according to imitative notions, is not to paint a tree as any mortal ever saw it or could see it, when he looked at it as a whole. Too much detail for the conditions of a picture damage its verisimilitude as well as its art. Too vague a generalization is still more fatal, because it is wanting in particular truth. A drawing of a particular man so generalized as to be as much like any other man of the same race and clothing, would be an absurdity if it could be. produced, and the true artist has to consider how far he is to generalize, and how far he must particularize in order to produce the best result- one of truth combined with beauty and with suggestive power.

If a number of good and bad photographs are examined, it will soon be found that, in addition to their merits or demerits, as attempts at imitation, they will vary in approaching to or receding from the kind of delineation which great artists delight to give. The artist imitates the appearance of nature in which delicately graduated lights and shades indicate the forms of objects seen in and surrounded by an atmosphere. Photography has a constant tendency to the child's blunder of making hard firm outlines where nature avoids them. The best of the orthodox school of photographers mitigate this mischief, but we are not aware that any one besides Mrs. Cameron has fairly attacked and vanquished it, and thus established a connecting link far stronger than any which previously existed between photography and fine arts. Mrs. Cameron has been engaged for several years in this labour, and her productions have been for some time before the public; but some of her most recent works have been the most remarkable, and have called forth from artists of the highest eminence a very enthusiastic, and, as we think, richly deserved praise. Mrs. Cameron has especially devoted her talents to two objects, both usually neglected in photography. The first is the realization of a method of focussing by which the delineations of the camera are made to correspond with the method of drawing employed by the great Italian artists. The second has been the introduction of an ideal pictorial element, by selecting good models and calling forth the kind of expression

which a judicious artist would desire to enshrine in his work. The results of Mrs. Cameron's labours may be seen at Colnaghi's, in a large collection of photographs, varying considerably in merit and interest, but all bearing testimony to originality of purpose and artistic skill. Here we have the head of a boy, full of fire and expression, simple and grand as a sketch by Correggio, which it closely resembles. There is no dead mechanism of mere photography here, but emphatically a work of art, instinct with life and motion. The hair flows freely, as if the breeze had caught it, the outlines are soft and melting, the play of light on the blooming features marvellous to behold. In another piece the same boy figures as Love in Idleness, a handsome mischievous urchin playing with his bow. An exceedingly well-managed group represents May Day; two other portraits are combined into an artistic and effective Prospero and Miranda. Other subjects of Mrs. Cameron's skill give us Esther and Ahasuerus, Friar Laurence and Juliet; while single figures, remarkably like drawings by great artists, are named, The Mountain Nymph, Sweet Liberty, Adriana, Sappho, Clio, Christabel, etc., etc.

In some of these cases we do not find ourselves able to follow the suggestions given by Mrs. Cameron in naming her pieces, the Greek ones especially seem to us, as a rule, to have much more of the character of medieval Italy; but no one, free from professional photographic prejudice, can see them without being struck with the high degree of artistic merit which they possess, and the contemplation of works so original and so beautiful, leads to the conviction that photography need not remain in the lower stages of a mere imitative craft. Mrs. Cameron not only claims for it, but wins for it, the dignified position of a fine art, and we are glad to notice that copies of her works are offered for sale at very moderate prices. It is good for artists as well as amateurs that there should be this sort of competition. Ladies, like Mrs. Cameron, who break through the conventional nonsense which attempts to scorn industry the moment it seeks for profit, are doing good service in their day and generation. It is probably not of the slightest consequence to her whether she gains or loses by photographic pursuits, but, as her works are substantially good, and capable of multiplication, she is morally right in letting the public have the benefit of them, and economically right in accepting whatever legitimate profit they may produce.

A

DECEPTIVE FIGURES;

WITH REMARKS ON SATURN'S "SQUARE-SHOULDERED" PHASE.

BY R. A. PROCTOR, B.A., F.R.A.S.

IN the April number of the INTELLECTUAL OBSERVER, p. 224, instances have been given of an optical illusion affecting our estimate of the relative size of figures placed in particular positions with respect to each other. In the figure accompanying this article a somewhat similar illusion affecting shape is illustrated; the lines A B and B C, which appear to have a decided curvature, being in reality straight lines.

In figures constructed on a larger scale, and with concentric circles closer together (in proportion), the deception is still greater; and it is remarkable that the illusion is increased by drawing equidistant lines radiating from the centre of the concentric circles. I notice, also, that a want of symmetry in the drawing seems to destroy the illusion.

The deception struck me as remarkably perfect in the case in which I first observed it. I had drawn the meridians and parallels for a polar star-map on the equidistant projection, to the scale of an 18-inch globe-the parallels to every degree, and the meridians, from the 20th parallel of N. P. D. to the bounding parallel (N. P. D. 37° 23′) of the map, also to every degree. Thus the map formed a circle 11 inches in radius, with 37 concentric circles crossed by 360 radiating lines, drawn with as much uniformity as possible. Now before marking in stars, I wished, as a matter of curiosity, to determine the exact figure on the equidistant projection of the spherical pentagon, which in my gnomonic maps appears as a true pentagon. I accordingly drew in, in pencil, first the inscribed pentagon, and then (through points determined by their known R. A.'s and N. P. D.'s) the five curved sides of the figure I required. Thus the sides of the true pentagon formed chords of the five sides of a curvilinear pentagon