Liber horarum dominus mearum Indoli moremque gerens, honestis Quo libet solus vager, ambulansque Thus done into English by the young Etonian:- Lord absolute of my own acts and hours, Let me at will, alone, still wander forth, Horace's sapphics." The old family pictures, though not of high merit, are to be preserved, and the walls of the new rooms require some good specimens of modern art. Mamma must have her children's pictures by Frank Grant and James Swinton, and a few costly miniatures of Thorburn and Ross, but the squire has a longing for a landscape of Callcott, or a scene by Phillip to remind him of an early ramble in Andalusia. The yearly visit to Town may be put down as a sacrifice to fashion. But it is not for fashion that the family move in autumn to Scotland. The squire calls that his holiday. He has formed a second home in the glen where his boys have grouse-shooting and salmon-fishing, and the girls, if they don't make much of trout-fishing, at least learn to walk. They go down without equipage or horses, and live that free simple life which makes the month at the Glen the happiest of their year. They are getting very fond of half a dozen shepherds' families near them, and pretend that the Highlanders are more gentle, as well as more intelligent, than the sturdy clod-hoppers of their English valley. Returning from Scotland-business has accumulated, and the 1 The "English country gentleman" who penned these rustic rhymes was Robert Viscount Hampden. His collected poems-altogether delightful, if the shape and type were not too magnificent, were published at Parmatypis Bodonianis-by his son. The English Country Gentleman. 39 squire has not time for partridge-shooting but as needful exercise. A day of pheasant-shooting is hardly sport; but when his duties and occupations leave an idle day, with what pleasure does our squire mount his favourite old horse for a near meet of the Duke's hounds! Perhaps he might not have believed he had leisure, if the young Etonian who is at home for Christmas did not convince him. Together they ride out, and the boy admires "the Governor's" straight riding and knowledge of country. The frost comes just in time, for the full moon has brought a new flight of woodcocks, and the squire makes a holiday to show the young fellow some covert shooting, and make him admire the thriving new plantation and the rides he has cut through the old wood; and to be sure they are admired as only a son can admire a father's work and his own place. Our English country gentleman unlike his forefathers is quite temperate. The "October" of his grandsire and his father's bottle of Port are fined down into a glass of sherry and a pint of claret. His health is good, because mind and body are sufficiently occupied with cheerful and varied work. He is a good parent, master, landlord, neighbour. His people have always been so in worse times, and he is not to degenerate. It is a slander to say he prefers his pheasants to his tenants, and the cottages on his estate are in good repair as well as his kennels. He is a churchman, of the Established Church, and never thought of any other. The parish living is in his gift, and will be enjoyed by any one of the younger sons who takes to learning and shows a vocation. In politics the family have always been Tories, but our squire has outlived the delusion of " Protection to native industry" from finding that industry thrives best unprotected, and that his rents are rising under free trade. He confesses that the Reform Act was a bitter pill, but it has brought him and the neighbouring farmers to a kindlier understanding, and he is becoming quite acceptable on the hustings and at election canvasses. His son, the young Etonian, who is popular as the captain of the Volunteer Rifles, and leader of the village eleven at cricket, is even getting up some topics for a concio ad populum when he shall be old enough to stand for the neighbouring borough, and thinks of enrolling himself as a follower of Lord Stanley. We feel what we have written is a rough and unworthy sketch of the country life of England. It may serve our present purpose, which is partly to tell foreigners how we live. When any country can show the proprietors of its soil so occupied, so amused, it will have secured one element of the greatness and the happiness of Britain. ART. II.-1. Exposé de la Théorie Mécanique de la Chaleur. Par M. VERDET. Paris, Hachette et Cie., 1863. 2. Heat considered as a Mode of Motion. By JOHN TYNDALL, F.R.S. etc. London, Longmans, 1863. VARIOUS considerations appear to render it desirable that we should attempt to give a popular account of modern discovery with regard to the nature, and the mode of action, of Heat. And it will be peculiarly gratifying to our readers to find that to this country, which has so far outstripped the rest of the world in the development and use of machines in which heat is the motive power, is also mainly due the credit of having produced those philosophers who have traced to its origin the vast mechanical effect which is everywhere derived from the combustion of coal through the agency of the steam or the air engine. The only popular treatises on this important subject, with which we are acquainted, are indicated above, and will be examined briefly towards the close of the Article. What is Heat?-We have no wish to stupify our readers with the metaphysical arguments on this question, which, in countless heaps, encumber the shelves of medieval libraries; nor do we think that if we had ourselves attempted their perusal, we should now be able, with a clear head and unpuzzled mind, to sit down to our work. From the earliest times man's apprehension of the connexions and bearings of natural phenomena has been rendered uncertain and imperfect by his wilfully ignoring the great fact that Natural Philosophy is an experimental, and not an intuitive, science. No à priori reasoning can conduct us definitely to a single physical truth, and what has been called the Principle of Sufficient Reason has led to numberless mistakes in science, of the most pernicious character. Hence it matters not to us what Aristotle or Bacon may have laid down, Locke and Descartes imagined, or Leibnitz stolen, with regard to the nature of heat. Locke, it is true, was correct in his results, so far at least as our present information enables us to judge, but his method will not bear a moment's scrutiny. Let metaphysicians keep to their proper speculations, about mind and thought, where they are, at all events, safe from being proved to be in the wrong, however extravagant their conclusions may appear to the less presumptuous, and therefore (if on no other account) less fallible, student of the laws of matter. We shall not waste much time in a preliminary sketch of the early history of our subject. It might, perhaps, be made very attractive, but the materials for it have not yet, to our knowledge, been collected. The rapid march of modern discovery renders it not only useless, but destructive, to the progress of the Natural Philosopher to endeavour to explore the beginnings of his science. While he gropes about, seeking the source, his contemporaries are borne, with ever-increasing swiftness, along the broadening and deepening current of the river, to the "great ocean of truth which lies unexplored before them." In the physical world we are cognisant of but four elementary or primordial ideas besides the inevitable Time and Space. They are Matter, Force, Position, and Motion. Of these, motion is simple change of position; and force is recognised as the agent in every change of motion. Till we know what the ultimate nature of matter is, it will be premature to speculate as to the ultimate nature of force; though we have reason to believe that it depends upon the diffusion of highly attenuated matter throughout space. But, keeping to the four elementary ideas above, it is evident that to one or other of these every distinct physical conception must be referred. To which does Heat belong? The old notions of heat were that it was Matter; or, according to some philosophers, Force. It is only within about a century that proofs have been gradually arrived at that sensible, or thermometric, heat consists of Motion; while the so-called "Latent Heat" of Black may possibly not be heat at all, but may consist of Position. These are startling statements, as we have made them, but they will be fully explained, and to some extent developed, in the course of the Article. Thus it appears, that of the four available hypotheses as to the nature of Heat the two necessarily erroneous ones have, till lately, been almost universally adopted. So much for the trustworthiness of the metaphysical treatment of a physical question! Such a lesson should never be lost sight of; so deserved and so complete a refutation of the sophistical nonsense of the schoolmen, and so valuable a warning to the Natural Philosopher who is disposed to à priori argument as more dignified and less laborious than experiment, can scarcely occur again. Even the despised perpetual-motionist has more reason on his side than the metaphysical pretender to discovery of the laws of nature; he, to his cost-but to his credit also appeals to experiment to test the validity of his principle; but the mighty intellect of his rival scorns such peddling with apparatus, to it all truth is intuitive; nay more, what it cannot comprehend cannot be truth. But the days of its authority have nearly expired-luckily for human progress. When heat was considered to be matter, under the name of Caloric, it was regarded of course as uncreatable and indestructible by any process at the command of man. And we cheerfully allow that many very plausible explanations of curious physical phenomena were arrived at by the labour and ingenuity of the partisans of this theory. Thus it was natural to suppose, that when caloric entered a body, or rather combined with it, the body. should in general expand; and even when heating produced contraction there were analogies, quite sufficient to bear out the theory, supplied by such mixtures or alloys as alcohol and water, or copper and tin; where the bulk of the compound is considerably less than the sum of the bulks of the components. Conduction of heat, or transference of caloric from one body to another, or from part to part of the same body, also presented no difficulty. So it was with the experiments which led to what was called (from the principles of this theory) the specific heat of bodies; it had merely to be assumed that different bodies required different proportions of caloric to be mixed with them to produce equal effects in the form of change of temperature. Thus, the specific heat of water being called 1, that of mercury is 033, i.e., a pound of water requires 30 times more caloric to be mixed with it to produce a given change of temperature (measured by the thermometer), than a pound of mercury. The fact that in heating ice no rise of temperature is observed, however much heat may have been applied, until the whole of the ice is melted-and similar phenomena observed in every case of melting or liquefaction, as well as in boiling or vaporization-led Black to propound the doctrine of Latent Heat. The fundamental ideas of this doctrine, that water differs from ice at the same temperature simply by the admixture of a definite equivalent of caloric; that the steam which escapes from boiling water, though showing the same temperature to the thermometer, contains a vastly greater amount of caloric; and similar ideas. for all similar cases, were thus easily and directly reduced to the caloric theory. The additional quantity of caloric in such cases was supposed simply to change the molecular state of the body, without altering its temperature: hence the name. In all this there need be no hesitation, so far as we can see, in pronouncing the explanations given by the material theory of heat quite satisfactory, although in many cases they are certainly cumbrous, and difficult of application. But another class of common phenomena afforded no such easy application of the theory, namely, the development of heat by friction or concussion; and it must be allowed that many of the warmest supporters of the caloric hypothesis frankly admitted that their explanations of these effects were not quite satisfactory. The general tendency of these explanations was towards assuming a change in the capacity for caloric to be produced by the disintegration caused by friction or by the compression caused by impact-though it was excessively diffi |