Monkwearmouth, Sunderland, is the deepest coal-mine in all England; the coal being won at nearly two miles’ distance from the shaft, and upwards of 1900 feet, or more than five times the height of St. Paul’s, below the surface of the green fields and trees above. The pit employs nearly 300 hands, and yields between 500 and 600 tons of domestic coal per day; every few seconds, the tall cage shoots up out of the gloom of the shaft, and the tubs, like miniature railway-waggons, holding nearly half a ton each, are brought to the bank, and wheeled away in different directions. Not for a single instant does the work stop: it is coal—coal everywhere beneath and around; the very atmosphere is made gloomy with its fine particles; and all this, seen amid clanking of chains, roaring of steam, and the rapid activity and whirl of hurried business, make it one of the most curious and interesting scenes imaginable.

The dangers of the working are thus detailed. The boys in charge of the trams carry the “Davy,” the wire-gauze of which is far less liable to injury than the glass shade of the “Geordie,” or Stephenson lamp; and with these the lads may safely pass the “goafs” or worked-out seams, in which, though built up as far as possible, gas always lurks, though the invisible enemy around them is so thick that the gas will light inside their lamps and burn with a ghastly blue flame. Beyond this steep incline or bank there is still nearly a mile to be traversed to the “in-bye”—the face of the working, the spot from which the coals are actually won: where, too, the gas has its head-quarters, and has to be watched and guarded against every hour and minute of the day and night, for the work of a mine never stops, and day and night are meaningless terms in such eternal gloom and silence. The heat at the bottom of the bank, indeed in all parts of the mine, is very great in the extreme depths of Monkwearmouth. It is seldom less than 84 or 85 deg., and at the workings often over 90 deg. So great is the heat, in fact, that the men nearly always work almost naked, and in some cases absolutely so. The heat certainly does not arise from want of proper ventilation, which seems ample. Not much bratticing is used to convey the air through the workings, and it is almost entirely confined to the places where the coal is won. In fact, as far as human ingenuity, skill, or experience can go, the pit is made safe from gas at least. Its only risk seems to be from shaft accidents or inundation, to both of which more or less all colleries in this district and near to the sea are, to say the least, equally exposed and equally protected against, as far as it is possible to do it.

Iron as a Building Material.

Iron has been cited in Deuteronomy as the essential and last fruit of the promised land. Our interiors, as halls and churches, will assume new development and grandeur by iron, since we have seen 200 feet span at Birmingham without abutment, and 150 feet at Paris in still more enduring structure. The Pantheon of Rome, Sta. Sophia, St. Peter’s, the Baths, and the great Riding-house at Moscow, will hide their glories; and iron will henceforward dispense with pillars and clerestory, flying buttresses and abutments, and roof our churches in bold and single spans. With all due reverence for antiquity and precedent, we ought to open our eyes to the reconciliation of this new material and its peculiar faculties with the laws of proportion and taste; and this is a problem worthy of the best spirits, both as to the form of roofs or ceilings, and the form of supports, which, in iron, with 1-40th part of substance of stone, will give equal strength of support.

Iron may be termed the osteology of building. Hitherto the architectural system has proceeded on statics and equipoise of molecules, as if the human frame were built without bones. Now our buildings will have bones, giving unity and strength which never before existed. The nervures of the Gothic will now be in uniform and single arcs, erected at once: the library at St. Généviève, by Mons. Arbruste, exhibits an experiment in this way.

Concrete, not new.

Sheathing Ships with Copper.

From an old pamphlet we learn that:—“Mr. Pepys, a scientific man, in the reign of Charles the Second, suggested the great importance of Sheathing Ships with Copper, and urged the advantages with sound and persuasive arguments; and says, in some despair, ‘I wish it were tried on one ship.’ But this experiment was delayed for nearly a century; and when it was tried, although it answered beyond expectation, yet the prejudice against innovation was so strong, that in Admiral Keppel’s fleet, 1778, there was only one coppered ship.”

Copper-smelting.

Antiquity of Brass.

Brilliancy of the Diamond.

The cause of the wonderful Brilliancy of the Diamond is not popularly known. It has no inherent luminous power; it is simply transparent, like common glass, and yet, if the latter were cut into the form of a brilliant, it could no more be mistaken for a real one than for a sapphire or an emerald. The secret, therefore, of the brilliancy of the diamond must lie in something other than its clearness or its transparency. It is owing to its great refractive power. When rays of white light pass through transparent substances they are refracted, or bent out of their former course, and under certain circumstances are separated into their constituent elements, and dispersed in the form of the well-known prismatic colours. The cut drops of glass chandeliers show a familiar example of these properties. Now, the degree in which this effect is produced by any substance depends on the refractive power it possesses, and it so happens that the diamond has this power in an extraordinarily high degree, its index of refraction being 2·47, while that of glass, or rock crystal, is only about 1·6, and of water 1·3. The effect of this great refractive capability, particularly when aided by judicious cutting, is, instead of allowing the light to pass through, to throw it about, backwards and forwards in the body of the stone, and ultimately to dart it out again in all sorts of directions, and in the most brilliant array of mingled colours; and this is the marvellous effect that meets the eye. Sir David Brewster has shown that the play of colours is enhanced by the small dispersive power of the diamond, in comparison with its refractive properties.

The general value of diamonds has been rising of late years; for, though the production is not scanty, the demand, owing to general prosperity, and the extension of ornament to wider classes in society, is largely on the increase.—Mr. Pole; Macmillan’s Magazine.

Philosophy of Gunpowder.

New Pear-flavouring.

The new Pear-flavouring is derived from an alcoholic solution of pure acetate of amyloxide, considerable quantities of which are manufactured by some distillers, and sold to confectioners, who employ it chiefly in making Pear-drops, which are merely barley-sugar, flavoured with this oil. There is, also, an Apple-oil, which, according to analysis, is nothing but valerianate of amyloxide.

Methylated Spirit.

What is Phosphate of Lime?

What is Wood?

How long will Wood last?

Cedar-wood will last 1000 years. The oil of cedar-wood, mixed with oil of creosote and forced into timber by means of a pump, will be found highly preservative of all timber for shipbuilding and breakwaters. In very old buildings, the timbers where they have been whitewashed, are often found in the highest state of preservation. In olden days they cut the timber in the winter season, when the sap was most out of it; but now, for the use of tanners, it is felled in summer; the result of which is, that it shrinks, chaps, and decays, sooner than it otherwise would. The wood of the walnut-tree is very durable, and so is that of the horse-chesnut-tree. Many very ancient barns about Gravesend are built entirely of the last. In preparing wood for shipbuilding, &c., it is best to lay it in a “running stream” for a few days only, to extract the sap that remains in it, and then dry it in the sun or air, by which it neither chaps, casts, nor cleaves. The use of linseed-oil, tar, or such oleaginous matter, tends much to the preservation of wood. Hesiod prescribes “smoking” timber in order to preserve it:—

“Temonem in fumo poneres.”

Virgil advised the same method:—

“Et suspensa focis exploret Robora fumus.”

Others have advised the oil of smoke! [pyroligneous acid?] The solid stems of trees most subject to decay, are commonly found in the Irish “peat-bogs,” in such excellent preservation, that they are esteemed equal to any timber for substantial buildings; the peat being highly antiseptic and preservative. Larix (which can be procured in blocks of any size from Dantzig) is the best kind of wood for breakwaters, harbours, &c. It is capable of resisting the weather for a length of time in those situations.—Correspondent of the Builder.

The Safety Match.

In the first of these instances the sacrifice of life and wholesale destruction of property were traced principally to the fact of children inserting lucifer matches into various nooks and crevices, where an accidental concussion had produced their ignition. The next in the series of casualties are accidents resulting from the sudden ignition of boxes or bundles of phosphorized matches. The necessity as well as the possibility of removing the fatal cause of these accidents has long been felt; and by the following contrivance such occurrences, which hitherto have led to so many terrible disasters, may be completely obviated. This invention, which has reached us from France, consists of a match which cannot ignite by friction with ordinary substances, but which bursts into flame when struck upon a chemically-prepared substance, owing to the peculiar action occurring between the two bodies which are thus brought into contact. Without the prepared strip, the matches may be struck or trodden upon without the possibility of ignition. The advantage of having these articles tipped with a material which is not inflammable per se is sufficiently obvious, not only to careful housewives, but to the owners of large establishments where the ordinary “lucifers” are now used, and, we are afraid, often left carelessly about.

The reputed inventor of the Lucifer Match died in 1859, in Stockton, aged seventy-eight. The Gateshead Observer adds to this announcement:—“In the year 1852 (August), correcting the history of ‘matches’ in the ‘Jurors’ Reports’ (Great Exhibition), we stated, says our authority, that ‘A quarter of a century ago, Mr. John Walker, of Stockton-upon-Tees, then (as now) carrying on the business of chemist and druggist in that town, was preparing some lighting mixture for his own use. By the accidental friction on the hearth of a match dipped in the mixture, a light was obtained. The hint was not thrown away. Mr. Walker commenced the sale of friction-matches: this was in April, 1827.’ Dr. Faraday, it is said, first brought the discovery into general notice.”

Pottery.—Wedgwood.

Where there is coal there is generally iron, and iron works and earthenware manufactories naturally and unavoidably engender smoke; but although the inhabitants of the Potteries have refused to accept any compulsory measure, which, if recklessly carried out, might completely annihilate their trade and deprive of employment the vast number of the inhabitants of the district, yet there is no place where greater efforts have been made by private individuals voluntarily to adopt measures for the suppression of what they admit to be an evil, not in any degree to the extent set forth.

The first use of flint in pottery has been thus explained. A potter named Astbury, travelling to London, perceived something amiss with one of his horse’s eyes, when an ostler at Dunstable said he could cure him, and for that purpose put a common black flint into the fire. The potter observing it when taken out to be of a fine white, immediately conceived the idea of improving his ware by the addition of this material to the clay.

Imposing Mechanical Effects.

Mechanical force, when exerted even as a motive-power, can be employed by man on many a grand scale. The movements of massive pieces of machinery, even though moving aimlessly, still more when working for a purpose, always awaken in us the idea of power; and often also create emotions of awe and sublimity akin to those which are begotten by the spectacle of great natural phenomena. The sweep of a railway train across the country, and the dash of a war-steamer against the waves with which it measures its strength, never become paltry pageants, even though we are ignorant of the errands on which these swift coursers are bound. Still more striking are those actions of machinery which involve not only swift irresistible motion, but also transformation of the materials on which the moving force is exerted. Take, for example, a cotton-mill, which some never tire of representing as dreary and prosaic. In the basement story revolves an immense steam-engine, unresting and unhasting as a star, in its stately, orderly movements. It stretches its strong iron arms in every direction throughout the building; and into whatever chamber you enter, as you climb stair after stair, you find its million hands in motion, and its fingers, which are as skilful as they are nimble, busy at work. They pick cotton and cleanse it, card it, rove it, twist it, spin it, dye it, and weave it. They will work any pattern you select, and in as many colours as you choose; and do all with such celerity, dexterity, unexhausted energy, and skill, that you begin to see what was prefigured in the legend of Michael Scott, and his “sabbathless” demons (as Charles Lamb would have called them), to whom the most hateful of all things was rest, and ropemaking, though it were of sand, more welcome than idleness. For our own part, we gaze with untiring wonder and admiration on the steam Agathodæmons of a cotton-mill, the embodiments, all of them, of a few very simple statical and dynamical laws; and yet able, with the speed of race-horses, to transform a raw material, originally as cheap as thistle-down, into endless useful and beautiful fabrics. Michael Scott, had he lived to see them, would have dismissed his demons and broken his wand.—Prof. George Wilson.[15]

Horse-power.

The First Practical Steam-boat.

Mr. Macquorn Rankine, in supporting the opinion of Mr. Benet Woodcroft, that the title of the “first practical steamboat” is due to that vessel in which the double-acting cranked steam-engine—in short, Watt’s rotative engine—was first applied to drive the propeller,—proceeds on the principle, that to constitute a “practical” machine, that machine must be capable, not merely of working well during a series of experiments, but of continuing to work well for years, with ordinary care in its management and repairs. Such certainly never was, and never could have been the case, with any steam-boat in which the wheels were made to turn by means of chains and rachet-work—a sort of mechanism which may answer its purpose during an experiment, but which must rapidly wear itself out by shocks and rattling. Such an engine is not a “practical steam-engine;” and a vessel driven by it is not a “practical steam-boat.” Hence the importance which Mr. Rankine is disposed to ascribe to the first actual use of a permanently efficient rotative steam-engine to drive a vessel.

It may be true that as an original inventor, Symington ought to be ranked below his predecessors; because his steam-boat of 1801 was only a new combination of parts which had previously been invented separately by others—the paddle-wheel, by some unknown mechanic of remote antiquity; the application of steam to drive vessels, by a series of inventors, comprising Papin, Hulls, D. Bernouilli, Jouffroy, Miller, and Taylor; and the rotative steam-engine by Watt: still, the merit of having first used a “practical steam-engine” to drive a vessel is due to Symington.—Communicated to the Literary and Philosophical Society of Manchester, 1863.

Effect of Heavy Seas upon Large Vessels.

The Railway.

Meanwhile, the Railway is yet an incomplete invention; and it is contended that our passenger-trains are deficient in the requisite accommodation for the comfort and even health of the passengers, who are still exposed to an unnecessary vibration which, in the course of continual travelling, produces nervous diseases. Mr. Bridges Adams, the engineer, and therefore a practical authority upon the subject, maintains that the railway companies are so fettered in their operations as to be unable to make feasible improvements: were these restrictions removed, Mr. Adams contends the public would receive the advantage in many forms, in easier and cheaper transit, and in reciprocal relations of town and country, such as involve a revolution in our national economies. The same acute writer anticipates the time when our towns shall have their railway-streets, which may become a fact at no very distant future. London has already its subterranean railway; above, the air is grilled with the electric-wire railway; and the street-system is being commenced upon the banks of the Thames, and the stream is already bridged with viaducts.

Accidents on Railways.

The question of Railway Accidents involves the whole question of railway management in detail. Accidents may be called the weak points of the system, where imperfection is manifested, where failure crops out, and where the line of demarcation may be drawn between the practicable and the impracticable. “If the road is perfect,” says Captain Huish, “if the engine is perfect, if the carriages are perfect, and I will go on to say, if the signalman is perfect, and if everything about the railway is perfect, almost any amount of speed that can be got out of an engine may be done with safety. But we deal not with theoretical excellence, but with practical facts, and none of these things are perfect; and in a large machine like a railway they cannot always be kept perfect.”

Safety to life and limb is of course the most important consideration in the working of railway traffic. Yet the problem is substantially this:—There are upwards of one hundred and forty millions of passengers and seventy million tons of goods per annum conveyed over our railways; assumed that all these must be transported by railway, what is the best way to do it? It must at the best be by a species of compromise; there must be a limit to tentative measures, there must be a risk. “If you do not go at all,” says Mr. Seymour Clarke, “there is no risk of an accident; if you go one mile an hour it is more risky than if you stand still; it is a natural attendant upon all travelling, that there is a liability to accident of some sort.” And, again, Mr. Locke thinks “that where you have the certainty of inflicting an inconvenience on the public by a prospective advantage in the saving of an accident, you should be very careful how you entail perpetually recurring inconvenience for the sake of preventing an accident which may never arise.”

The Evidence adduced before the Select Committee of the House of Commons on railway accidents in 1858, from which the foregoing extracts have been made, has led the committee to the conclusion, that accidents on railways arise from three causes—inattention of servants; defective material, either in the works or the rolling stock; and excessive speed.

Railways and Invasions.

Connected with the Brighton Railway system alone there are 145 locomotive engines, 1858 carriages or passenger vehicles, and 2588 waggons and trucks or merchandise vehicles, for working 240 miles: on the South-Eastern there are 179 engines, 972 carriages, and 2535 waggons, for 286 miles; and on the South-Western, 177 engines, 850 carriages, and 3488 trucks, for 444 miles. These numbers might be increased to any amount, if increase were required, at a day’s notice, by aid from the gigantic resources of the more extensive systems north of London. Excursion traffic is more difficult to manage in many respects than military traffic. A word from the commanding-officer procures an amount of order in the one case which barriers and policemen fail to do in the other. A hundred thousand men may at any time be conveyed without fatigue from London to Brighton in a single day, and they may further be transported along the coast from point to point, to Portsmouth and Weymouth on the west, and to Dover on the east, without break of gauge. They may also be brought from the north through London, and from the north, via Reading, without coming to London at all; and, indeed, the means of communication thus afforded are of so much importance to successful defence, that the railway system determines to a great extent in this country, as it has notably done in America, the strategic lines along which offensive operations must be carried on, and defensive movements effected.—Quarterly Review, No. 223.

What the English owe to naturalized Foreigners.

Our mechanical proficiency, however, has been a comparatively recent growth. Like many others of our national qualities, it has come out suddenly and unexpectedly. But, though late learners, we have been so apt that we have already outstripped our teachers; and there is scarcely a branch of manufacture in which we have not come up to, if indeed we have not surpassed, the most advanced continental nations.

The invention of the steam-engine, towards the end of last century, had the effect of giving an extraordinary impetus to improvement, particularly in various branches of iron manufacture; and we began to export machines, engines, and ironwork to France, Germany, and the Low Countries, whence we had before imported them. Although this great invention was perfected by Watt, much of the preliminary investigation in connexion with the subject had been conducted by eminent French refugees: as by Desaugliers, the author of the well-known Course of Experimental Philosophy, and by Denis Papin, for some time Curator of the Royal Society, whose many ingenious applications of steam-power prove him to have been a person of great and original ability. But the most remarkable of these early inventors was unquestionably Thomas Savery—also said to have been a French refugee, though very little is known of him personally—who is entitled to the distinguished merit of having invented and constructed the first working steam-engine. All these men paved the way for Watt, who placed the copestone on the work of which the distinguished Frenchmen had in a great measure laid the foundations.

Many other men of eminence, descendants of the refugees, might be named, who have from time to time added greatly to our scientific and productive resources. Amongst names which incidentally occur to us are those of Dollond the optician; and Fourdrinier, the inventor of the paper-making machine. Passing over these, many were the emigrés who flocked over to England at the outbreak of the great French Revolution of 1789, and who maintained themselves by teaching the practice of art, and by other industrial pursuits. Of these, perhaps, the most distinguished was Marc Isambard Brunel, who for the greater part of his life followed the profession of an engineer, leaving behind him a son as illustrious as himself,—Isambard Kingdom Brunel, the engineer of the Great Western and other railways, the designer of the Great Eastern steam-ship, and the architect of many important public works.—Abridged from the Quarterly Review, No. 223.

Geological Growth.

Geologists who are familiar with the idea of Geological phenomena worked out through periods of inconceivable duration will, perhaps, be able to appreciate Mr. E. B. Hunt’s argument on the growth and chronology of the great Florida reef. After stating the dimensions of the reef, Mr. Hunt proceeds: “Taking the rate at twenty-four years to the foot, we shall have for the total time 24 × 250 × 900, on the data, as stated; or we find the total period of 5,400,000 years as that required for the growth of the entire coral limestone formation of Florida.”

“Implements in the Drift.”

We have already, at page 59, referred to these important evidences, in connexion with the mode of life of the present inhabitants of Tierra del Fuego. The geological inference must, however, be drawn with extreme caution, which induces us to return to the subject.

The period of time long before history was, for convenience we designate the “Stone Age.” We gather from manifold evidence that during this period metals were unknown. Wherever their use was introduced, there the “Stone Age” virtually ended. The recent discovery of the flint instruments of the drift seems to carry the “Stone Age” back to a period of which, till very lately, we had no idea. The interval between the time when men fashioned these thousands of implements already found in the drift, and the earliest examples of the second “Stone Age” so to speak, as the Danish “kjökkenmödding,” or the oldest Swiss “pfahlbau,” must be long indeed.

The above observations were communicated to the Times, April 30, 1863: it is but a glimpse of a great subject, but is so suggestive as to be entitled to attention.

The Earth and Man compared.

Why the Earth is presumed to be solid.

Besides the confirmation of some of the most material points of the theory of gravitation which results from the experiment of “Weighing the Earth,”[16] it furnishes a presumption of the strongest kind that the earth is solid to the centre, and not, as many have supposed in every age, a hollow shell. The mean density, 5⅔, is very much greater than that of the substances which abound at the surface. All common rocks are under 3, and nothing under the ores of the heaviest metals comes up to 5⅔. The earth is as massive as if it were all composed of silver ore, from the centre to the circumference, so that there must be an increase of density towards the centre. If those who think the earth to be a shell were to presume that its solidity ceased at 500 miles below the surface, they would then be compelled to give to the terrestrial matter, one part with another, a density greater than that of mercury, in order that the whole shell, the hollow part included, might have the mean density which is found by this experiment.—Penny Cyclopædia.

The Centre of the Earth.

Lt.-Col. Sir Henry James writes to the Athenæum as follows:—In verifying on a globe the interesting fact stated by Sir John Herschel, in his Outlines of Astronomy, and by Sir Charles Lyell, in his Principles of Geology, that the central point of the hemisphere which contains the maximum of land, falls very nearly upon London, or more exactly upon Falmouth, our most western port of departure for all parts of the habitable globe, it occurred to me to inquire what would be the central point of that portion of the globe which should include the whole of Europe, Asia, Africa, and America; and I found that the point lies in lat. 23° 3´ on northern tropical line, and in 15° E. long., near a place called Ghad in Africa, about 700 miles south of Tripoli. But the portion of the globe which, from this point as a centre, includes the so-called four quarters of the world is as near as possible two-thirds of the surface of the sphere; and I found that by projecting this portion of the sphere upon a plane drawn parallel to the great circle of which the above defined centre was in the pole and at 20° from it, and from a point in the prolongation of the axis of this great circle distant one-half of the radius from the surface of the sphere, that the whole of the four quarters of the globe could be represented on one strictly geometrical projection. I have had this projection made by Mr. J. O’Farrell, one of the highly intelligent assistants of the Ordnance Survey. I believe this is the first time that two-thirds of a sphere has been presented to the eye at one view.

The Cooling of the Earth.

Our author, moreover, in the course of his arguments, meets with difficulties, the importance of which does not seem to have escaped him, since he endeavours to remove them by some rather doubtful assertions. To those, for instance, who would object to the supposition that any natural action could possibly produce at one instant, and maintain for ever after, a 7000 degrees’ lowering of the surface temperature of the earth, he replies:—“I answer by saying, what I think cannot be denied, that a large mass of rock exposed freely to our air and sky will, after it once becomes crusted over, present in a few hours, or a few days, or at the most a few weeks, a surface so cool that it can be walked over with impunity.” Now we do confess ourselves very much inclined to deny such a proposition. What kind of mass does our author mean? Is it a small mass? then he need but visit a gun foundry, where he will find pieces of ordnance still hot though cast several days before. Or is it a large mass, like a mountain? The nearest approach to it would be lava, which remains hot for weeks after the eruption, and for any larger mass there is no evidence either in existence or possible. But the immense difficulty of the subject may be inferred from the fact, that Professor Thomson himself further down makes an admission which is fatal to his own view, viz., that “if at any time the earth were in the condition of a thin solid shell of, suppose, 50 or 100 feet thick of granite, enclosing a continuous melted mass of 20 per cent. less specific gravity in its upper parts, where the pressure is small, this condition cannot have lasted many minutes, since the rigidity of a solid shell of superficial extent so vast in comparison with its thickness must be as nothing, and the slightest disturbance would cause some part to bend down, crack, and allow the liquid to run out over the solid.” What then, we may ask, becomes of the liquid theory altogether?—Galignani’s Messenger.

Identity of Heat and Motion.

George Stephenson’s remark, that the sun is the agent that drives our locomotives, has attained a wider and more definite meaning from modern investigations. It is now known, not only that heat and motion are mysteriously related, but that they are the same thing. From the researches of Mayer and Joule, Thomson and Rankine, it is ascertained that so much heat can be converted into so much motion, and the motion reconverted into the original quantity of heat. Sir William Armstrong says that a degree of Fahrenheit in a pound of water is the same thing as the force required to lift 772 pounds a foot high, thus testifying to the final and exact establishment of the largest generalization which modern science has made; and among the many fruits which cannot but flow from the discovery, one of the earliest is its application, by Sir William Armstrong himself, to test the waste of power in artillery practice, by observing the heat called forth in the shot. Every degree of temperature added to the projectile is part of the force intended to destroy the target; and if it is asked what material makes the most effective cannon-ball, it is only necessary to ascertain what substance will keep coolest when it strikes the mark. It is observable that the convertibility of heat and motion opens up a new light into the ultimate constitution of matter. The marvellous experiments of Professor Tyndall on the power of the minutest films of gas and vapour to absorb heat, as a dark glass stops light, are equally interesting as valuable contributions to meteorology, and as a new mode of probing the molecular condition of the gases themselves. The laws of the variation of atmospheric temperature were unfathomable until it was discovered that the habitable quality of the earth depends on the floating vapour which clothes it, and which keeps it warm in exactly the same way as the coverings by which we protect our bodies from the inclemency of the weather; but the significance of these experiments goes far beyond the limits of a single branch of science, and again we seem to be hovering on the verge of large revelations as to the ultimate arrangement of the particles of matter.

It is in the development of new powers of testing the infinitesimal, and carrying research immeasurably beyond the coarse limits of microscopic vision, that the strength of recent effort has been displayed. The most startling result of this form of investigation is the insight which has been gained into the materials and the condition of the luminous atmosphere of the sun. It could scarcely have been anticipated that the nature of a body separated from us by millions of miles should have been discovered by experiments which deal with qualities hidden in the inconceivably minute dimensions which express the form and distances of what, for want of better knowledge, may still be termed the ultimate atoms of material substances; and yet it was by testing the light-stopping power of thin films of different vapours, that philosophers have felt themselves entitled to say that some of the same substances which we are familiar with on earth have contributed to the atmosphere of the sun.—Saturday Review.

Universal Source of Heat.

Dr. Percy, in his very able Treatise on Metallurgy, gives an explanation of the principle that the sun is really the source of the heat-producing power of all fuel; and we are inevitably reminded of the question with which George Stephenson puzzled Buckland. “Now, Buckland,” said Stephenson, as they were looking at a train in motion, “can you tell me what is the power that is driving that train?” “Well,” said the other, “I suppose it is one of your big engines.” “But what drives the engine?” “Oh! very likely a canny Newcastle driver.” “What do you say to the light of the sun?” “How can that be?” asked the Doctor. “It is nothing else,” said the engineer: “it is light bottled up in the earth for tens of thousands of years; light, absorbed by plants and vegetables, being necessary for the condensation of carbon during the process of their growth, if it be not carbon in another form,—and now, after being buried in the earth for long ages in fields of coal, that latent light is again brought forth and liberated, made to work, as in that locomotive, for great human purposes.” Dr. Percy explains the process by which this light or heat is stored, and discusses the question of fuel in all its forms and branches. We find under this head, inter multa alia, an account of the manufacture of the peat-bricks in South Bavaria, which have for some years past been used for the boilers of locomotives; again, an explanation of the failure of Mr. Vignoles’s process of manufacturing iron in Ireland by means of peat charcoal, in consequence of the value of the raw material so much exceeding his estimate; besides an elaborate discussion on that litigated question so differently judged by different tribunals, and still undecided—“What is or is not coal?”

Inequalities of the Earth’s Surface.