and rendered possible by corresponding separate action in the organs of vision, each of which is directly connected with different brain hemispheres. But it will be found, upon experiment, that you can read as rapidly with one eye as with two, and thus the theory of duplex action conspicuously fails.

The retardation referred to must therefore be regarded as the equivalent of the cerebration involved in the act of recollection, unconscious as was its exertion in the assumed case.

And the equivalent thus ascertained is fixed, as is clear from the data, at a point of minimum effort, which in the case of memory is obviously also the point at which an estimation, to be of value, would have to be taken; for a minimum of exertion in recalling verbal matter necessarily corresponds with a maximum of rate, and we have already shown sufficient reason for adopting this phase of mental action as the true basis of measurement. We have thus arrived at a further quantitative expression of some value, for memory is undoubtedly the most invariable constant in our mental constitution. From the moment when the wail of the new-born infant breaks upon the ear of the smiling yet anxious faces which surround it, to that in which the hoary centenarian totters peacefully into his grave, oppressed with the snows of over a hundred winters, there is no waking instant in which it is not incessantly present in every mental combination that can be formed.

There is, it must now be remarked, some collateral evidence of the actuality of the retardation just referred to, which may readily be cited. It is usual, and probably correct, to regard those as the most powerful minds which admit of the greatest amount of concentrated effort, and it must therefore, a fortiori, be very safe to assume that such minds are at any rate not deficient or wanting in vigor. From all physical analogy, again, it would appear only reasonable to suppose that when the mental force is concentrated, there

ought, other things being equal, to be a corresponding rapidity of ideation. Combining these two propositions, it should follow that great thinkers are also rapid thinkers. But the facts appear to lie the other way. This rapidity has certainly not been specially characteristic of men who have greatly excelled in high mental achievements. It would be at least as nearly true to say of them that the efficiency of their mental process has been in proportion to the slowness of its exercise, a fact which has its counterpart in the circumstance that men occupied in the active pursuits of life, and well adapted by the agility of their minds for such pursuits, are seldom profound thinkers. Even the brilliancy of Sheridan's wit is connected by his biographer, Moore, with the natural slowness of his mind. Descartes, perhaps the most original of philosophers, spent sixteen hours a day in bed brooding over his conceptions. Sir Isaac Newton would sit for over an hour on the side of the bed when dressing, with one leg in his nether garments and one leg out of them, a position which would be impossible to an agile-minded man. Adam Smith, one of the most original of thinkers, was so extremely absent, that the market-women thought him daft, and on one occasion he walked out of his house, out of his garden, and several miles along the road, partially clothed in his dressinggown, and was only aroused from his reverie by meeting the people going to church.

From the general considerations with which they have just been prefaced, it is probable that in these illustrative cases, and many similar ones which will occur to you, there existed, in combination with the highly concentrated mental state, a real retardation of thought, caused by the powerful exercise of memories loaded with appropriate knowledge, and focussed upon the individual points under consideration.

In the supreme effort of contemplation, the thinking at a thing, by which Newton devised the principle of fluxions,

vigilance of the bird is at its finny prey glimmering under A familiar way in which ordi

and in virtue of which other great original conceptions have been formed, the mind must therefore be conceived of as almost at a standstill. It floats with a poise like that of the sea-gull on the wing, when the highest stretch in quest of the the rolling waves beneath it. nary mortals like ourselves may produce an analogous result, is by trying to recall some name or thing we have forgotten. It will be found that the retardation produced by a determined effort of this sort, when the difficulty of recollection is sufficiently great, will bring the process of thought almost to a standstill. And these various data not only confirm the theory of retardation we have derived from another source, but also serve to show that this retardation of memory, under the phase of maximum exertion, may be looked upon as reducing constructive ideation to its zero.

The method which has been thus adopted in dealing with the mental rate of the human mind, and the questions arising out of it, would leave an element of conspicuous incompleteness were it not now briefly supplemented by some investigation of the effect produced by the familiar phenomenon of distributed ideation. In the foregoing considerations we have dealt with concentrated states of mind. Its normal condition is one of much less tension. It is a matter of ordinary experience that human beings are able to receive several apparently simultaneous impressions, and thus to have different ideas forming contemporaneously. A man walks along the street with his ears open to all sounds, and his eyes conveying to his brain all the sights which confront him. And without his consciousness being in the least degree veiled to these things, he may at the same time be carrying out an intelligent train of thought which has no reference to the physical circumstances by which he is

surrounded. The degree to which consciousness can be thus distributed is not at present susceptible of exact definition. On a priori grounds, however, it is probable that it is limited by the number of the different senses with one or at most two phases over for the purely mental processes. In corroboration of this estimate, it may be remarked that it has been laid down by Sir William Hamilton that we can only retain in our minds about six ideas simultaneously. A much greater degree of proficiency in this direction is, however, claimed by certain Hindus, as the following extract from Mr. Monier Williams' writings will show. He says:

"During one of my visits to Bombay, he (Pandit Gattu Lālaji) called on me, accompanied by three amanuenses, and requested a trial of his powers, declaring himself capable of composing six sets of extemporaneous verses simultaneously on any six subjects and in any six metres I liked to select. I proposed three subjects—a description of Bombay, the advantage of Sanskrit learning, and the advent of the Prince of Wales to India-naming at the same time three of the most difficult metres I could remember. Without a moment's delay the Pandit dictated the required verses to his scribes with wonderful precision and rapidity. Impromptu versifiers of this kind are called Sighra-Kavis or Asú-Kavis. While I was travelling in the south of India, I was visited by a Sátāvadhānī, that is to say, a man who could attend to one hundred things at once. He could play several games of chess, write and repeat poetry, work out problems, and make calculations of all kinds simultaneously. I also heard of a Trins ádavadhānī, or man who could attend to thirty subjects. . Ashtāvadhānis, or persons capable of attending to eight subjects simultaneously, are by no means uncommon throughout all parts of India."

.

Somewhat analogous to the performance of these Hindoos is that of those European chess players who can play a number of games blindfold. Paulsen, for example, has played as many as twelve games simultaneously in this manner. But I am strongly of opinion that the case of the chess player, and also those cited by Professor Williams, are not

really cases of simultaneous thought upon different subjects, but rather instances of rapid alternation of thought from one subject to another,* the memory recording each consecutive state faithfully, so that when the intermittent ideation comes round to a dropped subject, it can at once pick the clue up again at the precise point at which it was before abandoned. That some less complex combination of simultaneous ideation may go on is possibly true, but it is more probable that there is in all cases which are so regarded a real alternation of mental effort, although that alternation may be so extremely rapid as to be imperceptible.

The immediate question, however, which is essential to our subject is how far the distribution of attention, whether really or only apparently simultaneous, affects the mental rate. For a definite result, it is again expedient to appeal to a verbal standard. It will be found upon experiment that although far from being an agreeable operation, it is not very difficult to pass through the mind a certain portion of wellknown verbal matter whilst at the same time engaged in reading another portion, which should of course be equally familiar. The result attained will be nearly constant in its total, but will vary considerably as to the relative quantity of each kind of matter which passes in a given time. There will be usually, as might be expected, more of the matter which is read than of that which is purely mentalised. But the total, taking each at the relative value previously indicated, will be nearly equal, for equal times, to the same total which would have been obtained by successive undivided efforts. So far, therefore, as an inference can be drawn, the area which can be gone over by dividing the attention is in any case no greater than

In the context of the above passages Professor Williams distinctly enunciates the same view. The article from which these extracts are taken is entitled, "Indian Powers of Memory," and appeared in the Athenæum of March 6th, 1880.