been founded upon such a discernment of moral qualities and distinctions, both in his own character and in that of others, as to demand the exercise of the moral reason. When we say that one man is simpatico and another antipatico, we are exercising a moral sense and discrimination of an intimate and explicit sort; and this determines us in receiving or refusing to receive men to our confidence. In deciding that he would not defend himself so as to escape death, the action of conscience, sustaining the highest aspirations and the noblest intrepidity, is clearly revealed. I admit that in the escape after the flight and pursuit at Delium, and in the waiting in the Lycæum, and in the matter of Plutarch's pigs, there is to be discerned rather the activity of prudence than of conscience. But on the supposition that the monitor of Socrates was a mature and experienced reason, the action of both prudence and conscience would be alike included. To this it may be objected, that Plato distinctly declares that the monitor of Socrates told him, not what things to do, but what things not to do; that inasmuch as conscience has a twofold office towards both good and evil, the Dæmonion could not be conscience. But to this objection two answers may be made. The first, that Xenophon and Plutarch directly say that the Dæmonion both enjoined and forbade, that is, pronounced for or against certain lines of action. The other answer has been anticipated by the statements of our Scholastic Philosophy. It has been shown that the action of conscience, when it suggests or approves anything, is less preceptible than when it disapproves or forbids. This may be seen by analogies. We are insensible of our continuous respiration, but distinctly sensible of the act of holding the breath; it is an actus imperatus requiring a conscious exertion of the will. Again, in walking, we are unconscious of the momentum of our pace, but conscious of any hindrance, and even of the act of stopping. The moral reason or conscience is always in activity, but with little or no reflex action upon itself, until something offends it. We are then conscious of a change of attitude, and of a recoil. For instance, the reason and conscience of Socrates permitted him freely to mix among men to cross-examine them, but not to enter into politics. In the former, he followed his own spontaneous inclination; in the latter, he imposed a conscious restraint upon himself. This is what Aristotle describes as prudence, or Ppóvnois. He distinguishes it from science, as being an intellectual habit conversant with practical and contingent matter; and from intuition, as being of details rather than of principles. He says that Ppóvnois, or prudence, is an intellectual virtue conversant about moral action. And he ascribes to it a power of sight, which is so trained and perfected by experience as to discern with an intuitive rapidity what is right or expedient in practice. He says that prudent men have a faculty which men call (Sewórns) skill, or ability, or resource, "the nature of which is to do-and to do correctly-the things which conduce to the end proposed. If this aim be good, the skill is praiseworthy; but if it be bad, it becomes craft." Wherefore Aristotle says, "we call prudent men skilful, and not crafty. But prudence is not the same as this faculty (i. e. dewórns, or skill. But the habit of prudence grows upon this eye, as it were, of the soul."* This is a precise description of the prompt and provident intuition, a sort of ayxivota, and evßovλía, presence of mind, rapidity of counsel, with which Socrates discovered the useful, or the expedient in matters of practice. But the nature of this intellectual faculty is, in the main, distinctly moral; and belongs to the region of conscience, or the discernment of right and wrong. This instinct or faculty of moral discernment is traceable throughout the whole history of the ancient world. St. Paul only affirms what all records of antiquity demonstrate in saying, "When the Gentiles which have not the law do by nature the things contained in the law, these, having not the law, are a law unto themselves, which show the works of the law written in their hearts, their conscience also bearing witness (συμμαρτυρούσης αὐτῶν τῆς συνειδησέως), and their thoughts the meanwhile accusing or else excusing one another."† Once more: it may be objected that it is not for us to theorize as to what Socrates ought to have understood of his own inward life, but to take things as he expressed them. To this I have already by anticipation made one sufficient answer. But I will add another. Socrates refused to be classed with the philosophers or teachers of Athens. He delivered no system of philosophy. He framed to himself no moral or mental science. He found philosophy in the hands of Physicists, or physical theorists, and Sophists. He thought the Physicists to be vainly curious, if not impious, in trying to discover what the Gods kept secret: he thought the Sophists to be venal, superficial, and immoral. He was the founder, not of a new philosophy, but of a new era in philosophy. He extricated the conceptions of God and of morality from the region and philosophy of matter, and set them in the sphere of mind. He brought down philosophy, as Cicero says, from heaven to earth, to the market-place, and the streets, and the homes and the hearts of men. He cross-examined every man he met with, politicians, philosophers, rhetoricians, painters, private citizens, artisans: but he framed no system, and laid down no theories; he made no analysis of the human mind. Lord Bacon is said to have created a Novum Organum in philosophy by questioning Nature. This Socrates certainly did by questioning man. His method was one of universal questioning, whereby he heaped up materials for his disciples, one of whom afterwards gave to them a scientific order and precision of expression which has formed the imperishable basis of mental and moral philosophy to this day. The Ethics of Aristotle analyze, lay out, distinguish, and define the * Arist. Eth. N. L. vi. xii. τῷ ὄμματι τούτῳ γίνεται τῆς ψυχῆς. 66 intellectual and moral processes of the human mind-modern metaphysicians must bear with me-with a truth which has never been surpassed. What Socrates felt, Aristotle has fixed by exact analysis. The character of Socrates is the opóviuos of Aristotle, the prudent man; but prudence is etymologically and essentially far-seeing, the perfection of the moral reason. "All men," he says, seem to testify that such a habit which is according to prudence is virtue. But it is necessary to make a slight difference, for virtue is not only a habit according to right reason, but inseparably joined with right reason; and prudence is the same as right reason on these subjects. Socrates therefore," Aristotle says, thought the virtues to be reasons rational habits, for he thought them all to be sciences, but we think them to be intellectual habits joined with reason. It is clear, however, from what has been said, that it is impossible for a man to be properly virtuous without prudence, or to be prudent without moral virtue."† Aristotle seems to me to give in this passage the psychological analysis of the intuition and providence with which Socrates was eminently endowed. His prudence or φρόνησις constituted the αὐτάρκεια, or self-dependence of reason in all questions of morality, of which Xenophon speaks. Nullum numen abest si sit Prudentia, nos te Nos facimus, Fortuna, deam coloque locamus. or The prudence of Socrates was his own moral state, and yet non sine Numine, for we may well believe that to him was granted no common share in the "Light that lighteth every man that cometh into this world." In saying this, I am not rejecting the supposition that the particular providence which never suffers even a sparrow to fall to the ground without its Creator's will, may have in a special way encompassed the life of a man who witnessed in a corrupt world to the lights of nature and to the laws of right. In the midst of an intellectual frivolity and a moral degradation never surpassed in the history of mankind, made all the guiltier by reason of the refined culture and luxurious civilization of Athens, Socrates bore witness, until seventy years of age, to the supremacy of prudence, justice, fortitude, and temperance, the four perfections of man in the order of nature. Whether the estimate I have given of the Dæmonion of Socrates be true or not, the inquiry in which we have been engaged is manifestly not a barren speculation. It sets before us a great moral example, it teaches us a great moral law, necessary to men at all times, vital to us in these declining days. I mean, that there is no way for men to attain their true dignity, nor to serve their age and * Prudens futuri temporis exitum + Eth. N. L. vi. xiii. country, but to be upright in conscience, and even at the cost of life to be both in public and private duty prudent and temperate, just and brave. It tells us with a thrilling human voice, and in the accents of our common humanity, that man's supreme rule of right is the moral reason or conscience; that the cultivation of the mere intellect, while the moral life and powers lie fallow, is the work of sophists, deceivers, or deceived, or both; that the education of man is his moral formation; that intellectual culture without moral goodness is a wildfire and a pestilence which makes havoc of men and states; that knowledge is virtue, and virtue knowledge; for that, unless we would maim and mutilate our being, the intellectual and moral powers of man must be simultaneously and equably unfolded and matured. These are axioms of the moral life; vital, I say, at all times and in all lands, but nowhere more in season and more wholesome than to us who, in the sudden growth of a vast maritime empire, splendid and unstable from its very greatness, in the refinements of luxury, and the inundation of a stupendous prosperity, seem to be developing some of the moral and intellectual evils which went before the fall of imperial Athens;-political factions, licentious freedom, sophistical education, a relaxation of moral and religious traditions, a growing scepticism, an unstable public opinion swayed to and fro by nameless hands, and by irresponsible voices. In such a public state Socrates lived and died, bequeathing to us this lesson-that Conscience is the Voice of God. WEEKLY EVENING MEETING, SIR HENRY HOLLAND, Bart. M.D. D.C.L. F.R.S. President, PROFESSOR TYNDALL, LL.D. F.R.S. On the Identity of Light and Radiant Heat. WHETHER we regard its achievements in the past, or its promise and tendency in the future, all that we know of physical science-every bent and bias which we receive from its pursuit-tends to confirm the dictum of the poet regarding this universe: "All are but parts of one stupendous whole, If I halt here, and omit the next clause of the couplet, it is not because physical science has arrived at any conclusion hostile to that "All are but parts of one stupendous whole, POPE'S Essay on Man, Epistle I., line 267. clause, at all events in its profoundest signification, but simply because what the poet goes on to affirm lies outside the sphere of science. We, as physical students, have to do with "Nature" only, and our view of nature could not be more happily expressed than by the figure employed by the poet. For our vocation, and the delight and discipline that it confers, do not consist in the registration of unrelated facts and phenomena; but in the searching out and discovery of relationship in a system, whose parts we hold to be as closely and definitely related to each other as are the various organs and functions of the living body itself. It was this spirit of search, this capacity and desire, developed amid natural agencies, to detect the lines of connection between these agencies, that gave for a time such keen interest to the discussion, whether light and heat were essentially different things, or whether a substantial identity subsisted between them. It is not so very many years since that most excellent experimenter and philosophical inquirer, Melloni, isolated from a solar beam a brilliant light, and finding it incompetent to affect his most sensitive thermoscopic apparatus, concluded that light and heat were essentially distinct. But in drawing this conclusion, Melloni forgot that he was implicitly dealing with an instrument of almost infinitely greater delicacy than his thermoscopic apparatus; he forgot that the human eye, and the consciousness connected with the eye, are capable of being vividly excited by an amount of force which when translated into heat might defy all the thermometers in the world to detect it. Melloni himself subsequently modified his conclusion. It is not so very long since the late Principal Forbes was eagerly engaged in establishing the important point that radiant heat, like light, is capable of being polarized. Since that time Knoblauch, Foucault, Fizcau, and Seebeck have applied their refined experimental skill to this question of identity; and those excellent investigators De la Provostaye and Desains, pushed the analogy between light and heat so far as to prove that the magnetization of a ray of light, in Faraday's sense of the term, has its parallel in the magnetization of a ray of heat. It was, however, in their private cabinets that these experimenters obtained their results, which were in most cases so small, as to require attention on the part of a skilled observer to detect them. But science grows; and our experimental means augment as our knowledge expands. Recent discoveries and improvements will, I trust, enable me to make evident to you, to-night, effects which have been hitherto confined to far more limited circles; some of which indeed have only been seen by the observers who first noticed and described them. And if those accidents which often hold sway over lectureexperiments of a delicate character should prove favourable, we may be able to push the subject a hair's breadth beyond the limits which observation has hitherto assigned to it. Heat is presented to us in two aspects: sometimes associated with |