BOOKS.

UNDER THE EARTH.*

THE civilization of a country, it has been said, may be measured by the amount of sulphuric acid or by the amount of coal which it produces. Looking at the statistics of British ,trade in these products, and in the materials manufactured by their aid, English- men may well be satisfied, for the present, with this statement. But in a country like our own, the treasures of the earth do not remain long concealed, and when once they have been discovered, all the ingenuity and the energy of an indomitable race is devoted to their development. Thus the time will arrive sooner or later, some say before three hundred years, when the increasing in- accessibility, paucity, and poorness of the native materials of our manufactures will combine to offer a serious obstacle to our further material progress. The vast coalfields and mineral stores of other lands will meanwhile be worked with more perfect appliances, and on a scale of greater magnitude, and in consequence the present chief industries of England will change their character or gradually forsake her shores. Yet this day, though it may be approaching faster than economists generally anticipate, is probably by no means so close as some alarmists seem to fear. But whatever be the probability of the rapid exhaustion of our fossil fuel, it will not prove an uninteresting or unprofitable task to notice some of the chief incidents connected with the winning of coal from the earth, and to glance also at the closely allied subject of the raising and working of various metallic ores.

A handsome volume, by M. Louis Simonin, on alines and iliners has been recently prepared for English readers by Mr. H. IV. Bristow. The French author has collected together with much assiduity a crowd of varied tales about mines and miners ; and he has illustrated his narratives by maps of mining districts, by drawings of mining apparatus and tools, by representations of the plants of the coal measures, by coloured pictures of minerals, and by sensational and imaginary designs portraying the terrible disasters incident to work under the earth. Of these various components of M. Simonin's book we cannot speak with equal praise. All the tales are interesting, most of them, doubtless, true ; the figures of coal plants are beautifully drawn ; the sketches and illustrations of mining methods, appliances, and tools are intelligible, instructive, and generally correct ; but the chromo- lithographs of minerals and ores are distinct failures, while the melodramatic pictures of accidents, possible and impossible, might have been omitted with advantage, for surely a subject like mining may be made picturesque without being made horrible. The majority of people think little and know little of underground life save through its disasters. A fatal explosion of firedamp, or the breaking of a beam, or an irruption of water occurs, then we are forced to take an interest in some great colliery, of which, though its coal may have warmed us, we never heard before. We wait with anxious hearts for tidings of rescue, or we realize the scene of bereavement at the pit's mouth when rescue has proved impossible or too late. We pity and help the living ; we draw a veil over the fate of the dead, and have no wish to discover the sad secrets of their grave. What but a morbid taste could imagine and present in a concrete form the horrors of such a scene ? But in M. Simonin's book to each kind of calamity a separate picture is dedicated. Figure 67 is a fatal ignition of a blasting charge, figure 69 is a still more deadly explosion of fire-damp ; while in figures 92, 93, 95, and 96 we have collisions, and falls, and terribly "critical situations" in the shaft. But the acme of horror is reached in figure 86. The mine falls in, and with its weight of rock, and *. Underground Life; or, Mines and Miners. By L. Simonin. Translated andedited by H. W. BriAtow, F.A.S. Illustrated. London: Chapman and Hall. 1869.

strain of timber, crushes a busy gang of workers into a ghastly confmion of agony and despair, stereotyped by instant death. Or, turn to figure 87; the water floods the workings, and we see the floating corpses of the men caught amongst the dead bodies of horses, or drifting down the timbered levels and dim galleries of the mine. In this, as through the other catastrophes delineated in this book, a miner's lamp burns steadily, convenient to illu- minate artistically the scene, but increasing, to those who know something of mine accidents, and of French designs of this type, the unreal character of representation.

Popular books of this class have often the great merits of being entertaining in matter and readable in style; but the method of their production generally limits very seriously their solid value. Men of real attainments in natural science, even if they have the inclination, can seldom afford the time necessary for the tedious work of selection and compilation. Thus this task is resigned to those who may possess leisure and imagination, but, in too many cases, neither accurate knowledge nor sound judgment. In the book before us, though the French author is not always a sure guide, the English editor has done a good deal to correct the defects and enhance the merits of the original work ; he might perhaps have done more. For instance, we think that he should have brought down, to a more recent date, the fossil botany of M. Simonin ; he would not then have made two genera, asterophyllites and calamites, out of one species. Thhnks to the researches of Carruthers, the former plant (p. 23) is now known to be merely the foliage of the latter. Then we have (p.290) thallium glass called re- fractory (in the fire), when refractive power (of light) is meant ; we read araucanian instead of araucarian, foramenifora for foraminifora, and so on, here and there, throughout the volume. But these and other blemishes can be easily removed in a second edition, and so we must be content for the present with the very considerable improvement which Mr. Bristow has without doubt effected in the material submitted to his revision. We have to thank him for much work now amalgamated with the original text, for many corrections and notes, and especially for some excellent maps, among which we may particularly name that of the mineral regions of Chile and those of the several British coal-fields.

We must now endeavour by a few extracts and references to give our readers some notion of that treatment of his subject of underground life which M. Simonin adopts. To coal, metals, and precious stones the three parts of the present work are respectively assigned, but coal occupies, as it ought, more than half the book. The strange history of its formation, the com- paratively recent discovery of its numerous uses, its still grow- ing employment, the dangers of its extraction, and its probable exhaustion are here duly depicted. We learn something of the life animal and vegetable of the coal periods, and how successive forests with dense undergrowths must have lived and died to form it. We learn that coal varies greatly in character, much of it being, as it were, imperfect or immature, or else loaded with earthy impurities. Some of it is so contaminated with sulphur in several forms of combination that it cannot be used for smelting purposes. Indeed, many attempts were made before coal was successfully employed at all in the manufacture of iron, some- where about the middle of the seventeenth century, though its use for fires had become extensive 400 years earlier. The national importance of coal is illustrated (p. 51) by the flourishing condition of Belgium, due chiefly to her singularly rich coalfield. An instance of the political aspect of a coalfield is given by M. Simonin. He says (p. 80) that when the Allies in 1815 revised the French frontiers, they endeavoured, under the guidance of a Prussian engineer, so to define her borders as to exclude her from any share in the workable coal measures of Saarbriick ; it seems, however, that available coal has since been found in this part of the French territory. Does coal exist under London? a question discussed by M. Simonin, will not lead, we trust, to the borings which he suggests should be undertaken at the public expense in order to answer it. Into the details of shafts, pits, levels, and pumps we cannot, of course, here enter, though we must refer, in passing, to the ingenious apparatus of Triger (really the invention of Brunel), for sinking shafts under water by means of a chambered cylinder, in the lowest division of which the excavator works under a pressure of air equal to three or four atmospheres. This pressure serves to keep all water out of the cylinder as long as the depth does not exceed about forty yards. M. Simonin relates (p. 97) that under these conditions the deaf recover their hearing tempo- rarily, but that the power to whistle is lost ! Another use of com- pressed air is fully described by our author (p. 176). When a collier or miner has been rendered insensible by afterdamp or other irre- spirable gases, succour can only reach him if those who are sent on

this mission carry with them a reservoir of pure air. The appara- tus of Ronquayrol, constructed on a familiar principle, was devised for this purpose. Into an iron cylinder air is pumped until a pressure of 25 to 40 atmospheres is reached. The volume of air thus forced in is ennugh, when expanded on a rush, to last the explorer some time, and may also be made to feed his lamp with the necessary medium of combustion. Where this apparatus is not at hand, the simpler contrivance of M. Galibut,—a large goat- skin inflated with air by means of a pair of bellows,—answers the same purpose.

The cost of beginning and working is sometimes enormous, especially where water-bearing strata have to be pierced ; in one instance, no less a sum than £100,000 was expended on a single shaft in a Durham colliery. When the shaft has been completed, it may be the scene of the most varied calamities, but it is in the workings themselves that the collier finds his most deadly and numerous enemies. Fire-damp burns, or, mixed with air, explodes ; choke-damp suffocates ; water drowns ; falls of roof overwhelm ; the coal itself ignites (pp. 106, 145, 179). M. Simonin describes in detail all these catastrophes, and many others, noticing their causes and their prevention, as well as the attempts to retrieve these disasters. He gives us, too, the premonitory symptoms which indicate them, "such as a tendency of the floor and roof of a level or working to unite, by a movement called a crush or creep, or, Scottic, a sit." Some pathetic tales of rescue from mining acci- dents are told by M. Simonin. Thirty years ago, in a colliery of the Loire, the men were driving the levels carelessly, and the accumulated waters of an old working rushed in. They rushed up an inclined gallery, but it had no outlet. How could it be known above-ground where the poor fellows had sought refuge ? The plans of the mines were studied, their place of working and their probable retreat partly ascertained, partly guessed. A gallery was driven in the right direction, the signal blows of the pick received no answer. But at length a faint suspicion of reply was heard ; then the sounds became more distinct, the miners were living. They were spoken to ; a hole was bored into their place of retreat. Into this hole a tin tube was now fitted, and broth was poured down it for the men who were still between deliverance and death. Then, at length, after a little more desperate work with the pick, they were set free (p. 188).

Another story. In October, 1862, the mine of Lalle, near Bessdges, in the Gard, was inundated, owing to an extraordinary storm of rain. Some of the miners escaped up" a shaft, closely pursued by the rising water. Others were imprisoned in the workings, and were considered beyond hope. Twenty-four hours afterwards a young rolly boy entered a gallery of the mine. He knocked on the walls, and thought he heard answering knocks. The engineers were told, the experiment was repeated, there was doubt about the fact. To their signals the miners' signal was re- turned ; sixty feet of rock intervened, it would take a month to cut through it at the usual rate, but they worked with tenfold speed. In two days they talked through the rock with the cap- tives, who said, "We are three." In another day they were reached, one, the youngest, sobbing, another in a high fever, the third dead (p. 192). In this inundation at Lalle 105 meu perished, three besides those mentioned above were saved, but only after they had remained in the heading of a gallery for thirteen days. One of these last miners was a child ; he swam about in the dark waters to find if possible a way of escape, but returned, after a fruitless search, exhausted and chilled, to his two comrades, who lay close to him to warm him, and then covered him with small coal, in which position he was found by his rescuers.

But we must leave these sad though most interesting narra- tives to glance for a moment at some of the points in coal-mining not yet noticed. M. Simonin devotes some space and many illus- trations to the subject of lamps. Of safety lamps of various kinds, those which depend upon electricity (p. 169) as the source of illuminating power, though costly in working, are the safest in use, and have in special instances been found very useful. As to the depth of coal-mines, we are told (p. 111) that the deepest in Great Britain is at Dukinfield, near Manchester ; it is 2,151 feet deep, and the temperature at the bottom is constant at 75° Fahrenheit. As to the areas of coal-fields, cost of raising coal, and a hundred other kinds of technical information, we must refer our readers to the pages of M. Simonin, where the reader will find a profusion of various and minute details and figures. For instance, he will learn (p. 108) that saw-cut wood rots in a mine very rapidly, that axe-cut wood lasts much longer ; that 101 millions of tons of coal were raised from 3,192 mines in Great Britain in 1866; that one life is lost for every 68,484 tons raised ; that the coal-miners in Great Britain number 320,663; that falls of roofs, &c., cause nearly three times as many accidents as explosions of fire-damp, &c.

We have no space to speak with adequate fullness of mining for metals and precious stones. To metals pages 275 to 486 are given, and it would be impossible to do justice to M. Simonin's attractive treatment of this subject in a few lines. We content ourselves with a few references to some of the most interesting topics of his chapters. The stone period of the human race was

followed in seine countries (Denmark, Peru, &c.) by a period when instruments of native copper were introduced ; then bronze, a

mixed metal containing copper and tin, displaced the pure copper ; and lastly, iron, still more difficult of extraction than tin, has received in later historic times an enormous extension of produc- tive usefulness. Iron in turn is beginning to give way in part at least, to steel, a metal which chemically differs from pure iron by one or two hundredths of carbon, but which in physical characters is as distinct as if it were another element altogether.

Much space is devoted to gold, silver, and platinum, the noble metals, or "princes of the mineral kingdom." We are here reminded of the great gold discoveries of the present day.

California's riches were detected by a labourer, James W. Marshall, in January, 1818, and in May the rush of gold-seekers to the valley of the Sacramento had fairly set in. The gold of North Carolina (p. 369) was discovered by three children in 1799. Their father kept the yellow pebble for four years, using it to keep the door of his hut closed or open. He sold it to a jeweller, in a neighbouring town, for 3f dollars ; it was a nugget of solid gold weighing 151b., and worth nearly £900! It appears (p.371) that the gold of New South Wales was first detected in 1839 and rediscovered in that and other Australian colonies from time to time for some years. Not till 1851 did it attract definite attention, then the usual rush from all quarters of the globe set in with extraordinary vehemence.

The riches in silver of some of the Chilian and Bolivian work- ings is very great. Potosi furnished to Spain during two centuries not less than £240,000,000 worth of solid silver. The silver not only occurs in several forms of combination, such as horn-silver, a compound of silver and chlorine, translucent and sectile ; but a large quantity of the unmixed metal is also found. Sometimes a

stratum of magnesian lime-stone is met with, as at Tres Puntas, in the great sandy desert of Atacama, and in this rock the silver is

disseminated in moss-like forms. When the earthy parts are eaten away by an acid, the silver is left, retaining the form of the frag- ment, and constituting a metallic sponge. It is to be regretted that the mines of Mexico, of the Central American Republics, and of Peru are in a great measure abandoned (p. 335), chiefly owing to the unhappy political condition of those countries.

We wish we could refer more particularly to other metals, such as the platinum of Rupsia, the quicksilver of Spain and California, and the tin of Cornwall. We merely note that M. Simonin has gathered about his descriptions of the workings and mines of these and other important minerals many features of antiquarian, artistic, and romantic interest. One story, of a copper-mine at Fahlum, Sweden, is given on page 429. In 1719 the body of a miner was recovered. It was completely preserved by the blue vitriol of the mine water. An old woman recognized the face and form of her long-lost lover, Gustave. She was 80, he had been vitriolized at 20. The stone celt from an ancient tin-stream work (p. 430), the ffint implements from the tomb of an Indian gold-seeker, of Chiriqui, Panama, and numerous lamps, tools, &c., from various ancient workings all over the world, confer a special historic interest on the latter part of M. Simonin's volume.

The account of precious stones, though generally accurate from a scientific point of view, is not given in so entertaining a manner as we expected. A few words, for instance, might have been added about the tricks by which buyers may be hoaxed, and would have proved at once useful and amusing. All the black and white onyxes of the shops are coloured artificially by being boiled with sugar or oil, and then with sulphuric acid ; orange topazes are " pinked " by heating them red hot ; bad turquoises are improved by a solution of copper; chrysoprases are boiled in sulphate of nickel; and blemished diamonds even may be sometimes improved by treat- ment with chlorine ; opals, too, may be warmed before being shown, by which means their fire is often notably increased; and poor stones may be backed with paint, or foil, or coloured glass. But there is another trick, which, though rarely practised, is very ingenious.

A murky greenish gem from India and Ceylon, called the zircon, or jargoon, is the subject of the experiment. These stones are occasionally found capable of being decolourized by heat. A suitable cut specimen is selected and placed in a crucible full of sand, then it is heated to full redness for some time. The stone when cold is found to have lost its colour and its cloudiness, and then approaches in lustre, hardness, and play of colours, or "fire," to the diamond itself. It is set in a massive ring of good gold and pawned for several times the value of the metal. The ignorant pawnbroker has mistaken the stone for an inferior but large dia- mond. Of course, as the jargoon has little commercial value, though of high scientific interest, the ring is never redeemed.