given to any one supposed to possess a sound judgment, and whose practice has been sufficiently extensive to have enabled him to form his conclusions from a very large number of accurately observed facts. Such an individual is naturally supposed to be in the most advantageous position to arrive at a correct opinion as to what measures are likely to prove really efficient. With reference, however, merely to the preservation of health, there exists no such difficulty. Health is nothing more than the natural, spontaneous, harmonious action of all the organs and functions of the body. These actions being, under similar circumstances, the same in all, can much more readily be submitted to the test of observation and experiment. Let, then, the existence of a physiological law be once arrived at by legitimate deduction from a sufficient number of ascertained facts-according to the established method in any other branch of physical inquiry-and we may be assured that health will follow all measures in accordance with that law, and disease be the consequence of deviation from it, with just as much certainty as we may calculate upon the conclusions derivable from given data, in any one whatever of the fixed sciences. So far, then, as physiological laws are satisfactorily made out, that department of knowledge, which has for its object to ascertain the manner in which the largest amount of health can be insured, may take its rank amongst those sciences. And to whatever extent regulations founded upon them are carried into effect, may a sound condition of the body be so far confidently looked for. Regularity and perseverance are, it is true, in every case essential requisites. Many will still tell us that they can violate these laws with impunity, and others will affirm that they have observed them without any benefit; and we may give both credit for sincerity. In the one case, the inherent power which the system possesses to repel and repair injury, has hitherto availed in a very vigorous constitution to counteract the danger. In the other, we need not institute any very searching inquiry to discover that a mere temporary and superficial observance has been yielded to measures which ought to have constituted daily habits. No wonder, then, that failure should have ensued.

A vast amount of suffering, it is to be feared, is still inflicted by causes susceptible of removal, but left in operation

either from ignorance or neglect of facts already fully established, or for want of a sufficient number of accurate experiments as data for fresh generalizations. Yet it is satisfactory to observe how much has been already effected, and to how great an extent diminution in sickness and mortality has been, as it ever must be, the necessary effect. This, as we have already hinted, has been amply proved by the best conducted statistical researches. Let any one compare the best and most popular works of the present day on the subject of "health" with those of Cheyne and others, which obtained an equal or greater celebrity about a century since, and he will readily see that the practical directions offered, rest altogether upon a different basis. In the one, we find abundance of crude theory-confident assertions, perhaps didactic injunctions from very partially observed facts— and the whole involved in an air of mysticism, if not designed to conceal a felt want of information, at least admirably adapted for that purpose. In the other, we have a systematic rejection, for the most part, of all preconceived theoryadmonitions and rules founded on the intelligible and unassailable basis of well conducted experiment and acknowledged fact; and if there be doubt and uncertainty, they are at least acknowledged and traced to their right source, and we are bid to wait till fresh discoveries shall have removed the obscurity under which the subject still rests.*

It is, therefore, to be hoped that increasing attention will now be directed to this most important subject, for such it undoubtedly is. Health is a blessing which, like many others, we know not how fully to appreciate, so long as it is an every day enjoyment. We need, for the most part, severe discipline to elicit any suitable feeling of gratitude for the longsuffering goodness of the great Author of our being, who, notwithstanding the curse entailed upon us, has permitted our organs and functions to be so admirably constructed and nicely balanced, that if they suffer not from self-inflicted injury, health is the natural result-disorder and disease events of comparatively but rare occurrence. "Who is he," says an old

* The writer would especially recommend to the attention of any one desirous of farther prosecuting this subject, the works, already referred to, of Dr. Andrew Combe, of Edinburgh-"The Principles of Physiology applied to the Preservation of Health," "The Physiology of Digestion," and "A Treatise on the Physiological Management of Infancy."

nary degree of concentration: the most nutritious food, if taken in excess, will oppress and derange, instead of nourishing the system. But, more especially that bodily and mental exercise, so healthful to man as an individual, so useful and essential to him as a social being, cannot with impunity be pushed in the least beyond the limit which is fixed by the very structure and powers of his corporeal organization. And finally, the period arrives to the most healthy and vigorous, when failure commences-when waste exceeds nutrition-when the powers of the system become less and less equal to the demands made on it, till at last they refuse altogether the very supply which can alone sustain and renovate them. "Man wasteth away: yea, man giveth up the ghost, and where is he?" Job xiv. 10. Yes-where then is he? for this is the one all-important, absorbing question, except as connected with which, all others are really valueless-Where is he? For, circumscribed as he was, he had hopes and fears, and desires and mental realizations too, which refused to be confined by any such limit; an inward consciousness that dissolution would form no boundary to his actual being, but rather would introduce him to a far higher, and more important, and, in all probability, a retributive state of existence. Where is he? In vain do we search the dictates of reason and the discoveries of science, to trace any correspondence between them and that mental constitution which God has given us. But faith does reveal the wondrous secret, and in the disclosures of the book of God we do trace likewise this final and most important analogy of all. The very life and immortality after which man has naturally such irrepressible throbbings of anticipation, has penetrated our other wise unbroken night, and been fully brought to light by the gospel. There we read, not merely in the lightning of Sinai, but in the combined radiance of all the Divine attributes, which emanates from the cross, that "the wages of sin is death; but the gift of God is eternal life, through Jesus Christ our Lord," Rom. vi. 23. There, too, faith points, even through the gloomy portals of the tomb, to a wondrous pathway, where no mortal vision can follow; which "the vulture's eye hath not seen," but the Forerunner hath passed over it, and it entereth into that within the veil. "Thou wilt show me the path of life."

Oh, how unlike the frail, uncertain, unsatisfying, dying existence, through which we are now passing. No deleterious agency can enter there; "the inhabitant shall not say I am sick;" no casualty can ever more risk a health which shall bloom on in immortal vigour, and never know a change; no danger will there then be of exhausted energies, or of toil protracted beyond a prescribed limit. "They serve Him day and night in his temple," but it is with a glow of activity subject to no weariness, nor any more demanding intervals of repose. A far other and higher instrumentality shall be employed for the renovation and continuance of that hidden, but eternal life, than any now made use of; nor shall a flaming sword ever again prohibit access to it. Eden's tree was soon forfeited, but "to him that overcometh will I give to eat of the tree of life, which is in the midst of the paradise of God." "In thy presence is fulness of joy; at thy right hand there are pleasures for evermore," Psa. xvi. 11.

D. W.

MANUFACTURE OF MOSAIC AT ROME.

LEAVING St. Peter's, we walked to see the manufacture of mosaic. It differs from the pietra-dura in this, that while stones are employed in the Florentine mosaic, the material used in the Roman is a composition of lead, tin, and glass, smelted and mixed with colours; of these there are said to be eighteen thousand shades. We walked through a long room lined with cases, in which these are arranged, to the workshops. Here we watched the progress of the mosaic manufacture for some time. In an iron frame is placed a stone, the size of the intended picture; and on it is spread, inch by inch, a kind of mastic, which, when dry, becomes as hard as flint. While yet soft, the workman inserts in it the small pieces of which the mosaic is formed, cut and ground with the utmost nicety to the shape required. The time necessary for the completion of these pictures is, of course, great, and the expense proportionate, some costing nearly five thousand pounds.

When the copyist has faithfully executed his task, there is still much to be done: the mosaic is laid on a table, and the interstices are filled with a peculiar sort of wax, prepared for this purpose; the surface is then ground perfectly smooth, and the whole polished. The subjects generally chosen are the finest

pictures of the old masters; and it is wonderful to see the beautiful copies produced by such mechanical means.-Letter from Italy.

CAPE PIGEONS.

As the wind died away, and the ocean smoothed her bosom, in latitude about thirty-two degrees south, our companions, the cape pigeons, no longer aided in their flight by the gale, settled upon the water, and swam about like ducks in a pond, and with quite as much familiarity. This afforded a fine occasion for our boys, who baited hooks, and caught them as so many fish, while the rest of the crew lined the ship's side, and became pleased spectators of the sport. Many of these birds were caught and put into the hencoops, where they remained till the following morn, when they were turned adrift, to stagger in awkward paces upon the slippery deck; for they cannot take to the wing, unless they have the opportunity of starting from some point of vantage, or the edge of the heaving wave. They bore captivity with resignation, and a "philosophic composure; and they might pass for sophs in this way, did they not quarrel and fight so perpetually when associated in confinement.

Among the birds which follow the ships that plough the southern ocean, there are none that display so much of the social feeling as the cape pigeon: the albatross wheels in silent flight, at a distance; the black petrel, with its keen eye, darts now and then across the stern; and the stormy petrel flutters over the ship's wake, beyond the reach of gun-shot: but the cape pigeon seems to delight in the neighbourhood of man, and it is a violation of the feelings of hospitality, when we kill or torture it for mere pastime. This propensity in the bird is not without its curiosity, as it exhibits a point of connection in habit with the duck and the goose, which are easy of domestication : to these it is related in form and proportions. One of these captives was dissected by the writer on the following day, amidst that stir and turmoil of the ocean which are so common in these stormy latitudes. The notes and sketches are now before him; but the whole of them would not present much entertainment to those who have not given their attention to the study of comparative anatomy. It may, however, be mentioned, that the stomach is long and capable of great distension. Its out

side is marked with lines, which are the divisions of the muscular layers. It contained a piece of potato, which had been thrown out of the ship. It seems by this, that they are omnivorous, or will feed indifferently upon flesh or vegetables. The gizzard was very small, but had a leathery or coriaceous lining, which is the characteristic of that organ. It easily separated from the outer parts, and came away like a little bag, just as it happens in one of our domestic fowls. The gizzard contained a few small stones, which seemed very remarkable, as the bird was many hundred miles from land, and spends its time chiefly at sea. It shows that the gizzard has the power of retaining such bodies, to assist it in the process of reducing the harder substances to a pulp for the purpose of nutrition.

The powers of flight with which the Creator has endowed this bird, are of no ordinary kind. When the ship is going at the rate of two hundred miles a day, it will fly round it, sheer off, or approach it, soar aloft, or descend, as if it were stationary. One that had lost a leg, and so was easily recognised, followed the vessel for two or three days while progressing at this rate. It was computed that it traversed in its evolutions at least five times the distance run by the ship, which would give it a journey of a thousand miles each day. They fly with little effort, as the strong wind bears them aloft, and aids their wings to resist the action of gravity. Their flight seems to be a series of manœuvres, and shows how nature has taught them the practical application of the theorem, called the resolution of motion. This is most pleasingly illustrated when they fly against the wind, in which case they always ascend, so that a part of its force is employed in carrying them on high, and so interferes not with their advance. The remaining part is easily resisted by the oary sweep of the wings. When they fly before the wind, they usually descend, so that the exertion to keep above the water must be very small. When they would stop suddenly in rapid flight, they whirl round several times like a hawk, to exhaust the momentum of their speed by parting it between a centripetal and centrifugal force.

LAW AND GRACE.

L.

THE law prepares the heart by conviction and humiliation; but it is only grace that writes the law in it.-Henry.