state in the islands of the Northern Ocean, appears almost inexplicable; and it must be either admitted that some catastrophe, such as an universal deluge, removed them from their natural sphere; or that there has taken place a radical change in the temperature of certain countries. It is well known that the internal temperature of the earth, has often much more caloric than the exterior atmosphere; and this might undoubtedly tend to produce changes in its climate. The presence of fish crustacea in the hardest rock, and remote from the ocean, cannot be fully accounted for by the Mosaic deluge. The most probable supposition is, therefore, that there have been great and universal revolutions in animated nature; and in these have been formed, it would seem, as many distinct creations, each one testifying to the skill and omnipotence of its creator. We are thus led to suppose that man is comparatively a recent inhabitant of earth; that ages before his appearance the world was peopled by vast numbers of living creatures, and that the stagnant ocean teemed with life!

Before the creation of man, there seems to have existed a species of monsters whose very figures appear to us so contrary to nature's laws as to make us regard them with that abhorrence with which we view the dreams of a disordered mind; and, indeed, it is quite incredible to suppose that man could have lived in happiness among creatures of such hideous formation as those of which remains have been discovered in the strata of our globe. What would have been our sensations, when the very air we breathed was the element which was made the vehicle of their transmission? When every grove that adorned the face of the earth might form the resort of creatures, the most terrible and voracious, against whose attacks the arms and ingenuity of man would be comparatively unavailing. Can we suppose that the all-wise Creator would have placed the noblest monument of his beneficence and power in a position of so much pain and discomfort? The darkness and devastation which covered the universe before the creation of the sources of light and heat, was a fit period for the production of this class of animals; but when man appeared, it was expedient that they should be banished from creation, so that harmony and beauty should be everywhere present. And it may here be observed, that these specuculations are not opposed to the Mosaic narrative. We are told that, "In the beginning God created the heaven and the earth;" but it is not told us what this beginning signifies. The veil of mystery thrown over the science of Geology, would induce some to shrink from its consideration; but the inquirer after truth may examine any theory, and any fact, without fear of injury to the cause either of sound religion or of true science.

When we meet with some massive piece of architecture in the recesses of the earth, we admire the genius and the perseverance of those by whom it was framed. The researches made by geologists have revealed some examples of power and skill of which we had previously no conception, and we should acknowledge the hand of their Almighty framer. Each successive era of our world seems to have witnessed the produc

tion of creatures of more symmetrical and perfect natures than before, and the mind of man finds here so ample a field for the exercise of his powers, that after a long life of well-regulated study, we think he would have to confess that the great facts of the natural history of the globe were yet unknown, and that all his research, after establishing a few truths, terminated at last in the labyrinth of doubt and speculation.

REMARKS ON ILLUMINATION.-No. I.

So varied and novel are the improvements daily being made in every method of Illumination, that a brief consideration of some of the more important ones, together with an inquiry into their principles and relative merits, may, perhaps, prove not altogether unacceptable.

All luminous flame mainly depends on two ingredients, viz., gaseous, usually hydrogen gas; and solid, in all ordinary lamps, carbon. On applying fire to these materials, the hydrogen gas, being the more inflammable, begins to combine with the oxygen of the atmosphere, and assumes the well-known form of flame, springing from the place whence it issues and gradually diminishing to a point; a very small luminosity is the result, attended, however, with considerable heat. The solid, that is, the carbon, now performs its part; in the flame of the burning hydrogen, in which it is floating in minute particles, it is brought to a bright red or nearly white heat; and it is to these highly-ignited particles that the flame owes by far the greater part of its brightness. At the high temperature to which these carbonic atoms have been raised, they are capable of uniting with the oxygen obtained from the air; and in this manner they pass out at the summit of the flame, in the form of an invisible gas called carbonic-acid. It will then be apparent, that to obtain a good light, a material must be used containing a sufficiency of carbon to fill the flame with luminous particles, and that a quantity of air must be supplied capable of yielding oxygen plentiful enough to unite with all the hydrogen and carbon, otherwise the flame will throw off small unconsumed portions of carbon-in plain language, our lamp will smoke. It is possible, on the other hand, to supply too much air,—a point of great importance, and one, as we shall see hereafter, that has been almost universally overlooked. The desirable end is, to keep each particle of carbon as long as possible in the flame, so that it may travel at a white heat from the bottom to the top, before it is converted into carbonic-acid gas; and if the air be supplied too freely, the carbon is removed from the flame, and in lieu of a brilliant light, there is the bluish flame of burning hydrogen.

We may also, before proceeding further, remark, that an object of the first consideration should be to obtain as much light as possible with the smallest quantity of combustible material; the importance of which will appear when we consider that it must be the quantity of fuel used, quite irrespective of the cost. The burning material consumes a considerable part of the respirable portion of the atmosphere, and always in proportion to the quantity of combustible burnt; the result of this con

sumption is the formation of deadly carbonic-acid gas: and on account of the abstraction of the oxygen, the remaining constituent of the atmosphere, nitrogen gas, is left to produce its deleterious effects; all these evils resulting in proportion to the quantity of inflammable matter employed, it is obvious how necessary it becomes to reduce, as far as possible, the amount we use.

If we examine the flame of an ordinary oil lamp, viz. a simple bunch of cotton threads, with one end of them in a vessel of oil, and giving a flame very similar to that of a candle, we may observe somewhat of the several states to which we have just referred. The flame is threefold; the external portion, which of course has the largest supply of air, is scarcely at all luminous, on account of the too rapid consumption of the carbon; the internal portion, or that next the wick, where there is gas in an unburnt state, owing to its having little or no air; and a middle, most luminous portion, in which the carbon is in a high state of ignition, but has a less supply of air. In general we find such a lamp as this smokes: to remedy this defect, the present Argand burner was introduced, in which, as is well known, a stream of air is admitted in the centre of the wick, by placing it between two concentric metal tubes, by which means the thickness of the body of the flame is much decreased, and the interior body of unburned gas very nearly disposed of; the perfection of the light from such a lamp, depends in a great measure on the fuel employed; fine sperm oil is by far the best, and indeed is the only combustible which should be used in these lamps, as in it the hydrogen and carbon are in such proportion, that a moderate supply of air is sufficient for the consumption of the latter. When this oil is used, a common Argand lamp may be looked upon as one of the most perfect with which we are acquainted; but as the price of sperm oil is too great to render the use of it generally economical, it became necessary to contrive lamps capable of burning the commoner varieties of oil. These, for the most part, contain a much larger proportion of carbon than sperm oil, and if we attempt to burn them in an ordinary Argand lamp, we obtain a very smoky flame for want of a larger quantity of air; the cotton also usually employed is too thin to admit of the passage of such thick matter as these highlycarbonized oils. To overcome this difficulty, what are called Solar lamps have been introduced. These consist mainly of an Argand burner and lamp, made with the tubes which supply the oil and the place for the cotton about twice the usual size, the cotton being also unusually thick to allow the passage of the viscid oil. To supply a sufficiency of air for the larger amount of carbon contained in the oil, the apparatus figured in section was adapted to it. a a represent the tubes for conveying the oil, bb the cotton, ce the outer tube of the burner, dd the inner, e e a ledge going round the outside of the tube cc, on which rests the metal cap ff, which reaches about half an inch above the bottom, and is there contracted to the size of the inner tube of the burner, being furnished with openings at the bottom for the admission of air. The chimney G is secured in its place by a screw ring fitting on to the cap f, which overlaps a flange at the bottom of G. By means of this

apparatus, the flame takes the figure shown at H. The action of this cap in assisting the consumption of carbon will be easily understood. The air entering by the holes

in f, is brought by the contraction at the top into the very midst of the mass of flame, instead of simply passing outside it, as in an ordinary lamp, thus coming into much more direct contact with the particles of carbon. The cap becoming hot, by means of the flames, raises the temperature of the air, and makes it act somewhat on the principle of a hot blast, as at a high temperature it much more readily serves to consume the carbon: Another action of the cap is to contract the flame, and thus bring the same number of particles of carbon into a smaller space, so that the brightness and density of the flame is much increased. This part of the principle has been applied to lamps for burning a

H

description of oil that does not require an oxidator, by simply having a contraction in the chimney, at a short distance above the flame.

In both the lamps we have considered, the principles of due oxidation have been well attended to. In our next, we shall resume the subject, and point out how it has been since overdone.

REVIEW OF BOOKS.

Memoirs of DAVID NASMITH: his Labours and Travels in Great Britain, France, the United States, and Canada. By John Campbell, D.D., Author of the "Martyr of Erromanga," "Jethro," "Maritime Discovery," &c. royal 12mo. pp. 476. SNOW, London. It must be allowed that through the unparalleled triumphs of Missionary Enterprise in foreign climes, there has been awakened in the minds of Christians at home, a feeling of deep commiseration for the debased and ignorant of this country. The frequent announcements of the conversion to Christianity of whole multitudes; of the destruction of the idols of the heathen; of the reformation in their social and moral condition; were the means of directing the attention of the Christian public to the state of the heathen at home, and to the establishment of Societies for the promotion of Gospel truth amongst their own countrymen; and foremost among the noble band of men who stood forward to accomplish this end, was DAVID NASMITH.

He was born in the city of Glasgow in the year 1799, of respectable parents, eminently pious, and by them designed for the ministry; but owing to his unfitness for entering the University, (for at the grammar-school to which he was sent, "he learned absolutely nothing; he had not become master even of the. rudiments of the Latin tongue;") he was bound apprentice to a manufacturer of that city, in

which employ he remained until his eighteenth year. At the age of sixteen, he was admitted into the church assembling at Nile Street, under the pastoral care of the Rev. Greville Ewing. The following is the testimony to his character by his biographer when about this age :

"In this first stage of David's course, we everywhere see prudence regulating zeal, and zeal animating prudence. Seldom in a breast so young has so much ardour been so wholly free from the alloy of rashness. We nowhere meet with the slightest symptom of pride, conceit, or self-sufficiency. In his spirit, projects, and labours, heat and light uniformly appear in happy combination. He presents a lovely pattern to young men, whom the imitation of his example will not fail to conduct to happiness, usefulDess, and honour. This excellency in David was chiefly to be attributed to his deep acquaintance with the word of God, which was the subject of his habitual and intense study and meditation." p. 16.

His labours consisted chiefly in forming institutions for the development of young men's talents, and societies for visiting the dark and benighted portions of his land. He also for the same purpose proceeded to Ireland, and traversed that country, forming missions and other societies, too numerous to mention; from thence to the United States and Canada, planting missions at New York, Boston, New Orleans, Montreal, and at other places. On his return to Europe, he visited Paris, and succeeded there also in establishing a mission; and having (after a short stay in the French capital) arrived in London, we find his attention directed to the formation of a society since called, "The London City Mission:"-a society, the sterling value of which, in every point of view, no one can fully estimate, and which none but persons deeply embued with the self-denying and sympathizing Spirit of Christianity could ever continue in operation. The following the result of the Society's labours for two recent years, will give us some idea of its importance :-"763 persons of proficate character had been reclaimed and reformed, 179 persons who had made a profession of religion and had lapsed into an irreligious state were restored; 5,414 children had been sent to day and Sunday-schools; 1,422 persons had died upon the districts occupied by the missionaries, and not one of whom was visited by any religious instructor, except the missionary; 363 persons who died, had, in the judgment of charity, embraced the gospel, and departed in the possession of its consolations; 347 persons avowed that they had become decided characters, and were determined, by Divine grace, to lead a holy life, who had not then joined the Christian Church: and, in addition to the above, 244 persons made a public profession of religion, and became members and communicants of Christian churches. During the two years, 654,293 visits and calls were made upon the poor, of which 49,234 were to the sick and dying; 15,183 meetings were held for praying and expounding the Scriptures; and 715,440 tracts were given away." Well may the Author exclaim, "Who can estimate the importance, spiritual, moral, and political, of an institution of which such things can be reported? who can determine the claims of the memory of the man from whom that institution derived its existence? Is it saying too much to affirm that the arrival in London of David Nasmith was, in relation to eternity, an event of greater importance than that of all the ambassadors and statesmen, philosophers and kings who have appeared in it for centuries?"

To sum up the character of David Nasmith in a few words; we find the noble enterprize and manly courage of Williams, and the persevering zeal of Moffat, united with the philanthropy of Howard; pity and sympathy, for those around him were means by which his soul was aroused to action-but love to a Saviour, who had first loved him even to death, was the grand lever by which his spirit was stirred-the source from whence his noblest ideas were derived ;--for Him he desired to live, and in possession of His grace he calmly died.

Convinced fully that such a career is the only one that can afford that peace and joy" which passeth all understanding," we recommend most sincerely every young man to obtain a perusal of this book. Facts like these, speak with a terrible earnestness, and are far more calculated to fasten deep impressions upon the mind, than the most overpowering eloquence; decision of character and manly religious zeal, tempered with calm prudence, could never be so advantageously dwelt on or recommended, by minds of the highest order, as they are by the life and example of this eminent Christian. May each one be induced to make David Nasmith his model, and to devote himself, as he did, to the cause of humanity and religion.