maxims of his laboratory, explain morality by sal, sulphur, and mercury, and allegorize the scripture itself into the philosopher's stone. It is of no small consequence to keep the mind from such a possession, which, I think, is best done by giving it a fair and equal view of the whole intellectual world, wherein it may see the order, rank, and beauty of the whole, and give a just allowance to the distinct provinces of the several sciences in the due order and usefulness of each of them." "The same reason," says Berkeley, "that bids me trust a skilful artist in his art, inclines me to suspect him out of his art. Men are too apt to reduce unknown things to the standard of what they know, and bring a prejudice or tincture from things they have been conversant in, to judge thereby of things in which they have not been conversant. I have known a fiddler gravely teach that the soul was harmony; a geometrician very positive that the soul must be extended; and a physician, who having pickled half a dozen embryos, and dissected as many cats and frogs, grew conceited, and affirmed there was no soul at all, and that it was a vulgar error."

These observations might be confirmed by a reference to the history of science. Before the time of Newton, the greatest hindrances in natural philosophy arose from men applying to it their previous notions. They confounded and mingled the phenomena of nature with their metaphysical speculations. Des Cartes, being a great mathematician, endeavoured to reduce nature to geometry, and so considered nothing in body but extension. The celebrated Dr. Hooke, whose genius was so strongly inclined to mechanics, and to

whom the art of watchmaking had, from his earliest years, been a favourite study, applied his notions to the explanation of the phenomena of the human mind, and endeavoured to account for its operations on the principles of mechanics. There is a curious fragment of this sort of physiologico-metaphysical speculation quoted by Professor Stewart, in his Philosophical Essays, in which the author speaks of a continued chain of ideas coiled up in the repository of the brain, the first end of which is farthest removed from the centre, or seat of the soul, where the ideas are formed, and the other end is always at the centre, being the last idea formed, which is always the moment present when considered. Hartley and Darwin being, from their profession as physicians, familiar with some of the phenomena and laws of matter, when they began to speculate on the human mind, reduced its faculties and its phenomena into materialism. In truth, the number of individual cases is endless, which might be adduced in illustration of Lord Bacon's remark already quoted; "that when men of confined scientific pursuits afterwards betake themselves to philosophy, and to general contemplations, they are apt to wrest and corrupt them with their former conceits."

"The propensity which all men have to explain the intellectual phenomena, by analogies borrowed from the material world, has its origin in an error, differing from that which misled Hooke and Darwin, only in this, that the latter, being the natural result of the favourite, or of the professional habits of the individual, assumes as many different shapes as the pursuits of mankind; whereas the former, having its root in the common

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principles and common circumstances of the human race, may be expected to exert its influence on the theories of philosophers, in every country and in every age. The one prejudice would have been classed by Bacon with the idola species; the other with the idola tribus.”

Now, as in practice this narrow way of judging is only to be cured by an extensive intercourse with men of different ranks, and professions, and nations; so in speculation we cannot promise ourselves an exemption from innumerable prejudices and mistakes, but by taking an enlarged view of the different branches of human knowledge. For though our acquaintance with many of them must after all be extremely superficial, yet it is sufficiently extended to keep it in continual remembrance, that what holds true in one science may not at all be applicable to another; and that therefore we cannot be sure of the accuracy of the judgments which we form, on subjects that are beyond the line of our pursuits.

Though it is not my intention to point out all the advantages to be derived from a general knowledge of science, I cannot but notice the important benefit which it affords us in that particular study to which we give our chief attention, by presenting it in new relations and under new aspects. It is this which gives a power to the man of general acquirements to bring a richness and variety of original illustration to the discussion of his subject, and to place it in such different lights as to surround it, even after it has been hackneyed by others, with all the air of novelty and freshness. This talent is, no doubt, accompanied with boldness of conception, and vigour of understanding;

but I believe it is very rarely possessed excepting by those who have enlarged their minds by various and comprehensive study; and who have added to their physical strength of intellect the treasures of wisdom which the industry of ages, and the phenomena of nature, place within their reach. They discover in their subject many points of resemblance and of contrast to other subjects, which, while they would never occur to persons of less cultivated minds, furnish them with the most copious and the most interesting elucidations; and thus, from the stores of their knowledge, which is ever growing and ever new, they pour forth from the high eminence to which they have been raised, the light in which others, less gifted, or less industrious, are doomed to walk.

We can easily conceive, that the knowledge of a being formed like ourselves, and placed in similar circumstances, if his life were sufficiently extended to afford him uninterrupted opportunities for the exercise of his faculties, would increase to a degree, not only beyond the limits of our present comprehension, but which, when considered in relation to our present attainments, might be denominated infinite; for, if he were to live a thousand years in the possession of his powers, the progress which he would make during the second century of his life would not only be the double of that which was made during the first, but in a much greater proportion; so that his acquirements in each of the following centuries would more than equal the knowledge that had been attained in all the preceding. “Our knowledge," says Maclaurin," is vastly greater than the sum of all its objects separately could afford;

and when a new object comes within our reach, the addition to our knowledge is the greater, the more we already know; so that it increases, not as the new objects increase, but in a much higher proportion."

A third qualification, of essential importance in our philosophical inquiries, is a constant regard to the moral state of the heart. This has a much greater influence on our success in the discovery of truth than is commonly imagined. If, indeed, it were our object, in the studies to which we attend, to prepare ourselves for being accomplished disputants, it might be a matter of little consequence with what feeling we pursued them: it would, in this case, be our chief business, as it certainly would be our highest attainment, to know what was said, and the best manner of again saying it, rather than what is true.-But when it is our object to investigate the structure of our own frame, and the constitution of our mind,-to consider the nature of those duties which we owe to the Creator, to our fellow-creatures, and to ourselves,-and to carry our researches into the darkness of that futurity which lies beyond us, we cannot expect that our judgments should be accurate on subjects so elevated and so important, unless we cultivate a pure and devout state of heart. How different are the impressions which a growing acquaintance with the wonders of nature will produce on such a mind, from those that are felt by the man who never raises his thoughts to Him whose spirit lives through all his works; and who, while enslaved to vicious habits, is a stranger to the sublime pleasures of devotion! There is in this pleasure an ennobling influence which is not less favourable to the