A steam-engine may be called the greatest of inventions, and could the best one as yet constructed have sufficient consciousness to register its excellencies and defects, according to its own knowledge and experience, it could not be accused of boastfulness or self-depreciation. Again, if a dog could be endowed, in addition to its faculties, with the power of expression, and could define in exact terms its sense of smell and so announce it more keen than that of all other animals, it could not be accused of vanity.

The steam-engine in its revelation might reflect credit on its designer and on the man who constructed it, and these might reflect credit on their maker, but not on themselves; they had no hand in the acquisition of their faculties. So with the dog, it would simply make its statement, and in so doing communicate a phenomenon that the science of man would otherwise be slow to reach.

As it is with the dog, so it should be with men in giving expression to their natural gifts. A Shakespeare, knowing and avowing himself to be a vehicle constructed of phosphorized brain and ozonized blood, through which the higher revelations of nature are poured out on the senses of men, might describe the glorious machinery as it worked within him; might declare himself to be the most highly perfected of human beings, and that without vanity or boast, but not without a benefit to others, affording them details concerning himself absolutely unattainable by ordinary means; for no one has yet fathomed him as he did himself, and his knowledge died with him.

If Lord Bacon had taken the trouble to explain to us all about the wheels that moved his apparent delinquencies, it would have afforded a scientific lesson, and have ranked with his other essays. He would have lost nothing by it; minds of the size of his suffer nothing from opinion, and can be as indifferent to it as a cat, or a dog, or a horse, or a cow is to what we call decency. The degree of energy people display in vociferating against the anomalies of morals is the best measure one can have of their own failings. If I were to hear a man rail vehemently against a swindle, I should at once conclude that the machinery of cheating within him was in good working order, unless it had been his lot to be the party swindled.

There is no genius without humour, at least no literary genius, for that differentiating faculty is the basis of all self-criticism. Men have been challenged to define genius, and they have tried to do it without being asked. The fact is that clever people can do nothing unless it is a little difficult; they cannot see what lies directly under their noses, and one of the truths so situated is that perfect genius has never existed. Such genius as a man can possess is fragmentary, never whole. He may have literary genius, and that is enough for one. He may have scientific genius, like Goethe, Oken, Lamark, Geoffrey St. Hilaire, Darwin, Helmholtz, Davy, Faraday, Hunter, Cuvier, Laenec; but many of these were poor creatures in other branches than their own. He may have genius in mathematical philosophy, like Newton; but that great man had an intellectual weakness. Real genius of the perfect kind would be more than one man could carry; the ideal whole is broken up and distributed in fragments, some immense, like that falling to Leonardo da Vinci’s share, some small and constituting mere talent.

I have somewhere a list of men of genius who were originators, beginning with Homer as the father of Poetry, and coming down to Goethe who began the transcendental philosophy of to-day in his “Metamorphoses of Plants;” and I could never get beyond sixty or seventy names.

Any one giving an estimate of his own capabilities, whether favourable or unfavourable, or both, without illustrating what he states by his own work, and by the opinions of competent critics, is an egotist. If hereafter I should enter on the subject of my mental capabilities, it will be on the principle not of self-consciousness, but of mechanical candour. Having never ceased my work up to the age of eighty-four, I may have within me an ample experience of my mental operations; but any account of these the reader has the advantage of testing with what he finds his own superior judgment.

I produced very little in my early days, though a passion for literary success then governed me, alternating with a passion for scientific. A career in the direction of either was impeded in middle life by professional practice, which had its fascinations. But the young have not really much that is worth saying to the middle-aged or old. I had been nourished on the Greek and Roman classics; under the special influence of Herodotus I composed an Egyptian drama of the time of Cambyses, and it cost me much labour and greatly improved me in the art of composing; but not having read it for more than half a century I am quite unable now to judge of it. The flight I know to have been high, but whether through clear atmosphere or fog I cannot say. Sir Sibbald Scott, son of my friend Sir David, told me that he had seen the authorship of “The Piromides” inquired for in Notes and Queries at two different times. It was received by the press as a work of solemn purpose throughout.

I may mention that Lord Elgin, to whom I inscribed this play, thought it betrayed poetic taste, and he expressed his opinion in warmer terms than I cite.

It is surprising to witness how many good writers of their own language there are in this country: in reading the papers this is extensively seen; the leading articles appear equal, all marked by idiomatic clearness of expression. Then, in literary criticism, it is noticeable how much deeper the writers penetrate into the arcana, perceiving what is rendered, and what is left wanting, in a poetic composition, and that with a psychological acuteness much more general than was met with a generation or two ago. This is the more valuable, since criticism is the profoundest of studies; it demands an adequate knowledge of every science and art, as well as a competent observation of nature.

In speaking of my own intellectual mechanism, this I say once more is none of my own, but an instrument placed temporarily among visible things, to reveal what it may to the less knowing.