single sensation. As a mere description of the process, I cannot use a happier exemplification, than that which Condillac has given us in his Logique.

Let us imagine a castle, which commands, from its elevation, an extensive view of a domain, rich with all the beauties of nature and art. It is night when we arrive at it. The next morning our window-shutters open at the moment when the sun bas just risen above the horizon,—and close again the very moment after.

Though the whole sweep of country was shewn to us but for an instant, we must have seen every object which it comprehends within the sphere of our vision. In a second or a third instant we could have received only the same impressions which we received at first; consequently, though the window had not been closed again, we should have continued to see but what we saw before.

This first instant, however, though it unquestionably shewed us all the scene, gave us no real knowledge of it; and, when the windows were closed again, there is not one of us who could have ventured to give even the slightest description of it,-a sufficient proof, that we may have seen many objects, and yet have learned nothing.

At length the shutters are opened again, to remain open while the sun is above the horizon; and we see once more what we saw at first. Even now, however, if, in a sort of ecstacy, we were to continue to see at once, as in the first instant, all this multitude of different objects, we should know as little of them when the night arrived, as we knew when the window shutters were closed again after the very moment of their opening.

To have a knowledge of the scene, then, it is not sufficient to behold it all at once, so as to comprehend it in a single gaze; we must consider it in detail, and pass successively from object to object. This is what Nature has taught us all. If she has given us the power of seeing many objects at once, she has given us also the faculty of looking but at one, that is to say, of directing our eyes on one only of the multitude; and it is to this faculty,which is a result of our organization, says Condillac,-that we owe all the knowledge which we acquire from sight.

The faculty is common to us all and yet, if afterwards we were to talk of the landscape which we had all seen, it would be

very evident, that our knowledge of it would not be exactly the same. By some of us, a picture might be given of it with tolerable exactness, in which there would be many objects such as they were, and many, certainly, which had very little resemblance to the parts of the landscape which we wished to describe. The picture which others might give, would probably be so confused, that it would be quite impossible to recognize the scene in the description, and yet all had seen the same objects, and nothing but the same objects. The only difference is, that some of us had wandered from object to object irregularly, and that others had looked at them in a certain order.

Now, what is this order? Nature points it out to us herself. It is the very order in which she presents to us objects. There are some which are more striking than others, and which, of themselves, almost call to us to look at them; they are the predominant objects, around which the others seem to arrange themselves. It is to them, accordingly, that we give our first attention; and when we have remarked their relative situations, the others gradually fill up the intervals.

We begin, then, with the principal objects; we observe them in succession; we compare them, to judge of their relative positions. When these are ascertained, we observe the objects that fill up the intervals, comparing each with the principal object, till we have fixed the positions of all.

When this process of successive, but regular observation, is accomplished, we know all the objects and their situations, and can embrace them with a single glance. Their order, in our mind, is no longer an order of mere succession; it is simultaneous. It is that in which they exist, and we see it at once distinctly.

The comprehensive knowledge thus acquired, we owe to the mere skill with which we have directed our eyes from object to object. The knowledge has been acquired in parts successively; but, when acquired, it is present at once to our mind, in the same manner, as the objects which it retraces to us, are all present to the single glance of the eye that beholds them.

The description which I have now given you, very nearly after the words of Condillac, is, I think, a very faithful representation of a process of which we must all repeatedly have been conscious. It

seems to me however, faithful as it is, as a mere description, to leave the great difficulty unexplained, and even unremarked. We see a multitude of objects, and we have one complex indistinct feeling. We wish to know the scene more accurately, and in consequence of this wish, though the objects themselves continue as before, we no longer seem to view them all, but only one, or a few; and the few, which we now see, we see more distinctly. Such I conceive to be the process; but the difference is, that though we seem to view only a few objects, and these much more distinctly, the field of the eye still comprehends a wide expanse, the light from which scarcely affects us, while the light from other parts of it, though not more brilliant, produces in us distinct perception. It is vain for Condillac to say, that it is in consequence of a faculty which we have of directing our eyes on one subject, a faculty which is the result of our organization, and which is common to all mankind; for, in the first place, if this direction of our eyes, of which he speaks, on a single object, be meant, in its strict sense, of the eye itself, which we direct, it is not true that we have any such faculty. We cannot direct our eyes so as not to comprehend equally in our field of vision, many objects beside that single object which is supposed to have fixed our attention; and if, by the direction of our eyes, be meant the exclusive or limited perception by our mind itself, there remains the difficulty,-how it happens, that while light from innumerable objects falls on our retina as before, it no longer produces any distinct vision relatively to the objects from which it comes, while light certainly not more brilliant, from other objects, produces vision much more distinct than before. Let us consider this difficulty which, in truth, constitutes the principal phenomenon of attention, a little more fully.

When Condillac speaks of the faculty of the mind, by which he supposes it capable of directing the eye, exclusively, on certain objects, he must speak of that only, of which we are conscious, previously to the more distinct perception of those objects, as certain parts of the scene.

What is it, then, of which we are conscious, between the indistinct perception of the wide scene, and the distinct perception of parts of the scene?

In the first place, there is a general desire of knowing the

scene more accurately. This is the primary feeling of the process of attention. But this primary feeling is soon succeeded by others. Indistinct as the whole complex scene may be, some parts of it more brilliant, or more striking in general character, are less indistinct than others. There are a few more prominent parts, as Condillac says, around which the rest are indistinctly arranged.

With some one of these, then, as in itself more impressive and attractive, we begin; our general desire of knowing the whole scene having been followed by a wish to know this principal part more accurately.

The next step is to prevent the eye itself from wandering, that no new objects may distract it, and that there may be as little confusion as possible of the rays from different objects, on that part of the retina, on which the rays fell from the particular object which we wish to consider. We fix our eyes, therefore, and our whole body, as steadily as we can, by the muscles subservient to these purposes.

So far, unquestionably, no new faculty is exercised. We have merely the desire of knowing the scene before us, the selection of some prominent object, or rather the mere perception of it, as peculiarly prominent, the desire of knowing it particularly, and the contraction of a few muscles, in obedience to our volition.

No sooner, however, has all this taken place, than instantly, or almost instantly, and without our consciousness of any new and peculiar state of mind intervening in the process, the landscape becomes to our vision altogether different. Certain parts only, those parts which we wished to know particularly, are seen by us; the remaining parts seem almost to have vanished. It is as if every thing before had been but the doubtful colouring of enchantment, which had disappeared, and left to us the few prominent realities on which we gaze; or rather, it is as if some instant enchantment, obedient to our wishes, had dissolved every. reality besides, and brought closer to our sight the few objects which we desired to see.

Still, however, all of which we are truly conscious, as preceding immediately the change of appearance in the scene, is the mere desire, of which I have spoken, combined certainly with expectation of that more distinct vision which follows. There may

be a combination of feelings, but no new and peculiar feeling, either as simple, or coexisting with other feelings,—no indication, in short, of the exercise of new power.

Even though we should be incapable, therefore, of understanding how the desire should have this effect, it would not be the less true, that the desire of knowing accurately a particular object in a group, is instantly,—or, at least, instantly after some organic change which may probably be necessary,-followed by a more vivid and distinct perception of the particular object, and a comparative faintness and indistinctness of the other objects that coexist with it; and that what we call attention is nothing

more.

Are the comparative distinctness and indistinctness, however, a result which we had no reason to expect? or are they not rather what might, in some degree at least, have been expected, from our knowledge of the few physical facts with respect to our co-existing sensations, which I have already pointed out to you, and from the circumstance which we are next to consider? We have seen, in the observations already made by us, that many coexisting perceptions are indistinct, and that when one becomes more vivid, the others become still fainter. All that is necessary, therefore, is to discover some cause of increased vividness of that one to which we are said to attend.

If we can discover any reason why this should become more vivid, the comparative indistinctness of the other parts of the scene may be considered as following of course.

Such a cause exists, unquestionably, in that feeling of desire, without which there can be no attention. To attend, is to have a desire of knowing that to which we attend, and attention without desire is a verbal contradiction, an inconsistency, at least, as great as if we were said to desire to know without any desire of knowing, or to be attentive without attention.

When we attend, then, to any part of a complex group of sensations, there is always an emotion of desire, however slight the emotion may be, connected exclusively with that particular part of the group to which we attend; and whatever effect our emotions produce on the complex feelings that accompany them, we may expect to be produced, in some greater or less degree, by the desire in the complex process which we term attention.