that arrests and concentrates the attention, a feeling not lodged in the eye, but in the mind at large. In the case of Geometrical forms, there is also a secondary or additional susceptibility springing from the depths of the mind and concentrating nervous energy upon them. What this susceptibility is there may be some difficulty in deciding. I am disposed to look upon it as the feeling that some minds have towards what is generalized and comprehensive—an intensity of regard drawn out by the concentration of meaning contained in the object. A circle viewed geometrically represents all the round forms in nature, and in it we may ascertain truths applicable to every one of these; and when the mind is of the kind strongly disposed towards truth and certainty, and naturally capable of being intensely concentrated, geometric forms ought naturally to arrest it. The hold that one must take of these figures is far more intense and severe than in any other class of forms; every line and every angle must be rigorously held up before the view. The nice degrees of curvature are not so necessary to retain as the lines and angles, these being the two elements that determine mathematical truth.

As regards forms that belong neither to Art nor to Science, and possess not the fascination of beauty or the interest of comprehensive truth, we must depend principally, I apprehend, upon the unheightened plasticity of the optic circles. Written language and arbitrary symbols in general are examples of this class. The power of remembering a great multitude of arbitrary marks appears to me to show the intrinsic adhesiveness of the muscular sense in the eye. The acquiring of the Chinese written language, with its many thousand characters, is perhaps the highest effort of this nature that could be fixed upon. When the forms are few and important, as the letters of Algebra, or the symbols of Chemistry, they will be seized by the mathematical mind, but when they are innumerable in amount, and not individually of stirring importance, they can be imbibed only by high natural or disinterested adhesiveness. This contrast of the intensive and the extensive expresses in a general way the difference of the man of science from the scholar; artistic considerations being equally foreign to both.

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The retention of a map or a complex plan belongs to the scholarly and not the scientific memory. I do not deny the existence of an additional stimulus of the nature of a scholarly interest in the end and purpose of maps and languages, but I do not think that this occurs so manifestly to heighten the plastic adhesion as happens in the two other cases.

24. In the foregoing discussion, I have treated the luminous effect of the objects as nothing in the account. The next class of examples are those where light, colour, and shade are a material part of the impression, as in a landscape, a spectacle, a picture, a room, a human face. Here the object consists of an aggregate of masses of colour, which are associated by whatever force of retentiveness and adhesion belongs to the impressions of colour. By repeatedly gazing at a picture, its different patches of colour seize hold of the mind and connect themselves in their natural order, so that the one can recal the rest, and the whole can exist and be held in the view when the actual object is no longer present. The masses of coloured decoration seen in theatres, the colours of rich calicoes, and the variegated dresses of an assembly of people, exemplify the cases where colour predominates over form, and where the retentiveness is much more optical than muscular. The impressibility to colour is put to the test by the attempt to recal objects like these. The geometrician needs no such faculty. A natural persistence in the currents of luminous action, and a rapidity in acquiring the transitions that fix one to another at its side, which make but one and the same quality of the optical circles, are shown when the visible world, not in outline but in picture, is easily retained in idea. This attribute has no necessary connexion with the muscular susceptibility; the two follow different laws, and belong to independent organs. In some people we find the luminous susceptibility powerful and pre-eminent; such persons have one of the gifts of a pictorial artist. The easy recollection and revival of scenes and objects and human faces are necessary in order to work as a combiner in this kind of material.

25. The same distinction as that above drawn, may be made between a natural or disinterested adhesiveness (always

the best), and an adhesiveness stimulated by a flow of cerebral power in consequence of excitement kindled by the object. An artistic sense may operate here as well as in forms; and if so, the pictures retained will be in preference those that rouse an artistic feeling. A natural impressibility to light will show itself in things that are indifferent to any deeper sense; as in recollecting the succession of houses and shops in a street, of the dresses of a company, of the features of an indifferent landscape, and of visible coloured objects in general, whether they have interest or not. This kind of susceptibility must be very great in such a mind as that of Dickens, who revels in the description of mere surface, creating interest out of the mere act of describing, as a painter makes an indifferent object pleasing by the display of imitative power. The remembrance that some people have of the minute particulars of a room where they have been for a short time, its furniture, walls, decorations, and details, implies, in the first instance, a natural retentiveness to visible effect, and particularly colour. This original susceptibility may be heightened by the habit of attending to such things and by the interest attaching to them, but these would not suffice of themselves, nor probably would they exist without the primitive quality. For it is a fact, that the discovery of æsthetic effects in coloured scenes usually accompanies the natural susceptibility to colour. Minds furnished with a large store of visible pictures as a consequence of their retentive faculty, are apt to become artists; as may be seen from the whole class of poets and writers of romance.

26. There is necessarily a process of successive growth in the Sensations of the eye, or in the pictorial impressions derived through its instrumentality. We acquire first the mere discriminative retentiveness of simple colours and outlines; we can say if the object now in the hand recals a former impression of the same nature, or if it be different from any given past impression. We pass from this on to pictorial retentiveness; the full realization of the object as an idea existing by its own power. This ideal conception begins with simple forms and slightly varied colours, before taking in the more complex appearances. A ring, a ball, a spoon, a dish, a

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table, a door, a window, are among the more elementary and easy objects; they imply a few simple motions and turns of the eye, and are mostly uniform in colour. These may all be conceived at an early period, and before a face or a human figure can be surveyed sufficiently often to hold its many phases in one cohesive embrace. I can easily suppose that it takes several years ere the retentiveness of visible aggregates is grown to the pitch of holding easily the whole picture of a human person, especially if we take an individual only once But the differences of susceptibility and of cultivation on this point are enormous: not to speak of the element of human interest that assists us so much in forming a cohering picture of this particular subject.

seen.

It must never be forgotten that the inward operations for holding a remembered or ideal picture in the view are the very same as the actual examination of the original. They consist in movements hither and thither of the eyes (these movements not often actually executed), resting occasionally on single points, while the rest drops out of view, then passing to other points, now making a wide sweep over the whole, at another time inspecting narrowly the parts. The movements and colour are fused in one complex impression; this fusion is one of the effects of the associating power: and thus the two mutually sustain and revive each other.

27. To sum up the circumstances that affect the adhesive growth of visible images. Distinguishing between the mechanical and the optical elements of the eye, we note a different law for each, inasmuch as they spring from independent portions of our framework; the one following the rule for mechanical ideas generally, the other being special as regards the susceptibility of the eye to light and the natural retainability of the impressions of light and colour. We then remark that, time or repetition being in all cases necessary, the process is shorter in some minds by virtue of the primitive adhesiveness of the nervous system, in others by the flow of cerebral energy determined by the exciting character of the subject, as when artistic forms are impressed under the artistic sensibility. These are permanent causes; being always at work if

they exist at all. The more temporary influences are those mentioned already in speaking of the growth of Movements; namely, the fresh and healthy condition of the organs; the freedom from distracting excitements and depressing passions, and any stimulants that may be occasionally applied to the attention, as the force of sympathy, an appetite or passion, some purpose or end in view. Lastly, we should advert to the vividness and clearness of the original objects, as when a country is seen under a strong sun-light, or when a picture is forcibly and distinctly painted. Feebleness, haziness, or indistinctness in any sensible impression whatever, necessarily weakens the stimulus given to the sensorial circles, and makes them so much the less adherent.

28. Constant allusion has been made to the superior retentiveness of the traces of the sensations of sight. This permanency is the life of the intellect; for although intellectual forms would exist apart from luminous impressions, yet the superiority of this one sense represses the growth of the others, and causes it to monopolize the office of representing the outer world in the mind.

If we look for a few moments at a strong light, and then shut the eyes, the light still remains, the excited retina keeps up the currents of visibility in the brain, and produces for a time nearly all the effects of the original object. Newton made an experiment of gazing at the sun, until the solar image took possession of his eyes, and sustained itself for several weeks against his will. The overpowering strength of the impression in this case produced a diseased persistency. A similar persistency is often caused by intense emotions, such as terror; a fright will make an object haunt a person for a length of time. Intense affections have a like influence in sustaining the ideal presence of their subject.

In ordinary circumstances, and in ordinary minds, an idea falls short of the sensation; the recalled picture drops out much of the original, and presents itself under feebler lights: but in vision less is missed than in the other senses. The vividness and the ease of an actual view can rarely exist; but under an average impulse, form, outline, and parts can be recovered when the