Imágenes de página
PDF

tates that reduction, is an instance of arrangement so happily suited to the purposes of human industry, that it can hardly be considered as recurring unnecessarily to final causes, if we conceive that this distribution of the rude materials of the earth was determined with a view to the convenience of its inhabitants."

Let us briefly consider what is the effect of mineral fuel, on the actual condition of mankind. The mechanical power of coals is illustrated in a striking manner, in the following statement in Sir J. F. W. Herschel's admirable Discourse on the study of Natural Philosophy, 1831, p. 59.

"It is well known to modern engineers that there is virtue in a bushel of coals, properly consumed, to raise seventy millions of pounds weight a foot high. This is actually the average effect of an engine at this moment working in Cornwall.'

The ascent of Mont Blanc from Chamouni is considered, and with justice, as the most toilsome feat that a strong man can execute in two days. The cumbustion of two pounds of coal would place him on the summit."

The power which man derives from the use of mineral coal, may be estimated by the duty* done by a pound, or any other given weight of coal consumed in working a steam engine; since the quantity of water that the engine will raise to a given height, or the number of quarters of corn that it will grind, or, in short, the amount of any other description of work that it will do, is proportionate to that duty. As the principal working of mineral veins can only be continued by descending deeper every year, the difficulty of extracting metals is continually on the increase, and can only be overcome by those enlarged powers of drainover matter has been increased seventeen fold since the first invention of these engines; and increased nearly threefold within twenty years.

* The number of pounds raised, multiplied by the number of feet through which they arc lifted, and divided by the number of bushels of coal (each weighing eighty-four pounds) burnt in raising them, gives what is termed the duty of a steam engine, and is the criterion of its power. (See an important paper on improvements of the steam engine, by Davis Gilbert, Esq. Phil. Trans. 1830, p. 121.)

It is stated by Mr. J. Taylor, in his paper on the duty of steam engines, published in his valuable Records of Mining, 1829, that the power of the steam engine has within the last few years been so advanced by a series of rapid improvements, that whereas, in early times, the duty of an atmospheric engine was that of 5,000,000 pounds of water, lifted one foot high by a bushel of coal, the duty of an engine lately erected at Wheal Towan in Cornwall, has amounted to 87,000,000 pounds; or, in other words, that a series of improvements has enabled us to extract as much power from one bushel, as originally could be done from seventeen bushels of coal. Thus, through the instrumentality of coal as applied in the steam engine, the power of man

There is now an engine at the mines called the Fowey Consols in Cornwall, of which Mr. Taylor considers the average duty, under ordinary circumstances, to be above 9,000,000; and which has been made to lift 97,000,000 lbs. of water one foot high, with one bushel of coals.

The effect of these improvements on the operations of mines, in facilitating their drainage, has been of inestimable importance in extracting metals from depths which otherwise could never have been reached. Mines which had been stopped from want of power, have been reopened, others have been materially deepened, and a mass of mineral treasure has been rendered available, which without these engines must have been for ever inaccessible.

It results from these rapid advances in the application of coal to the production of power, and consequently of wealth, that mining operations of vast importance, have been conducted in Cornwall at depths till lately without example, e. g. in Wheal Abraham, at 242 fathoms, at Dolcoath at 235 fathoms, and in the Consolidated Mines in Gwcnnap at 290 fathoms, the latter mines giving daily employment to no less than 2,500 persons.

In the Consolidated Mines, the power of nine steam engines, four of which arc the largest ever made, having cylinders ninety inches in diameter, lifts from thirty to fifty hogsheads of water per minute, (varying according to the season) from an average depth of 230 fathoms. The produce of these mines has lately amounted to more than 20,000 tons of ore per annum, yielding about 2,000 tons of fine copper, being more than one-seventh of the whole quantity raised in Britain. The levels or galleries in these mines extend in horizontal distance a length of about 43 miles. (See J. Taylor's account of the depths of mines, third report of British Association, 1833, p. 428.)

Mr. J. Taylor farther states, (Lond.- Edin. Phil. Mag. Jan. 1836, p. 67) that the steam engines now at work in draining the mines in Cornwall, are equal in power to at least 44,000 horses, one-sixteenth part of a bushel of coals performing the work of a horse.

ing which Coal, and the steam engine, alone supply. It would be quite impossible to procure the fuel necessary for these engines, from any other source than mineral coal.

The importance of Coal should be estimated, not only by the pecuniary value of the metals thus produced, but by their farther and more important value when applied to the infinitely varied operations and productions of machinery and of the arts.

It has been calculated that in this country about 15,000 steam engines are daily at work; one of those in Cornwall is said to have the power of a thousand horses,* the power of each horse, according to Mr. Watt, being equal to that of five and a half men; supposing the average power of each steam engine to be that of twenty-five horses, we have a total amount of steam power equal to that of about two millions of men. When we consider, that a large proportion of this pqwer is applied to move machinery, and that the amount of work now done by machinery in England, has been supposed to be equivalent to that of between three and four hundred millions of men by direct labour, we are almost astounded at the influence of Coal and Iron, and Steam, upon the fate and fortunes of the human race. "It is on the rivers," (says Mr. Webster,) "and the boatman may repose on his oars; it is in highways, and begins to exert itself along the courses of land conveyances; it is at the bottom of mines, a thousand (he might have said, 1800) feet below the earth's surface; it is in the mill, and in the workshops of the trades. It rows, it pumps, it excavates, it carries, it draws, it lifts, it hammers, it spins, it weaves, it prints."*

* When Engineers speak of a 25 horse Engine, they mean one which would do the work of that number of horses constantly acting, but supposing that the same horses could work only 8 hours in every 24, there must be 75 horses kept at least to produce the effect of such an Engine,

The largest Engine in Cornwall may, if worked to the full extent, be equal to from a 300 to 350 horse power, and would therefore require 1000 horses to be kept to produce the same constant effect. In this way it has been said than an Engine was of 1000 horse power, but this is not according to the usual computation.

Letter from J. Taylor, Esq. to Dr. Buckland.

* As there is no reproduction of Coal in this country, since no natural causes are now in operation to form other bods of ft; whilst, owing to the regular increase of our population, and the new purposes to which the steam engine is continually applied, its consumption is advancing at a rapid accelerating rate; it is of most portentous interest to a nation, that has so large a portion of its inhabitants dependant for existence on machinery, kept in action only by the use of Coal, to economize this precious fuel. 1 cannot, therefore, conclude this interesting subject without making some remarks upon a practice which can only be viewed in the light of a national calamity, demanding the attention of the legislature.

We have, during many years witnessed the disgraceful and almost incredible fact, that more than a million chaldrons per annum, being nearly onethird part of the best coals produced by the mines near Newcastle, have been condemned to wanton waste, on a fiery heap perpetually blazing near the mouth of almost every coal-pit in that district.

This destruction Originated mainly in certain legislative enactments, providing that Coal in London should be sold, and the duty upon it be rated, by measure, and not by weight. The smaller coal is broken, the greater the space it fills; it became, therefore, the interest of every dealer in Coal, to buy it of as large a size, and to sell it of as small a size as he was able. This compelled the Proprietors of the Coal-mines to send the large Coal only to market, and to consign the small coal to destruction.

In the year 1830, the attention of Parliament was called to these evils; and pursuant to the Report of a Committee, the duty on Coal was repealed, and Coal directed to be sold by weight instead of measure. The effect of this cnange has been, that a considerable quantity of Coal is now shipped for the London Market, in the state in which it comes from the pit; that after landing the cargo, the small coal is separated by screening from the rest, and answers as fuel for various ordinary purposes, as well as much of the Coal which was sold in London before tho alteration of the law.

The destruction of Coals on the fiery heaps near Newcastle, although diminished, still goes on, however, to a frightful extent, that ought not to be permitted; since the inevitable consequence of this practice, if allowed to continue, must be, in no long space of time, to consume all the beds nearest to the surface, and readiest of access to the coast; and thus enhance the price of Coal in those parts of England which depend upon the Coal-field of Newcastle for their supply; and finally to exhaust this Coal-field, at a period; nearer by at least one-third, than that to which it would last, if wisely ccoi

[graphic]

We need no farther evidence to show that the presence of coal is, in an especial degree, the foundation of increasing

nomizcd. (See Report of the Select Committee of the House of Commons, on the state of the Coal Trade, 1830, page 242, and Bakewell's Introduction to Geology, 1833, page 183 and 543.)

We are all fully aware of the impolicy of needless legislative interference; but a broad line has been drawn by nature between commodities annually or periodically reproduced by the Soil on its surface, and that subterranean treasure, and sustaining foundation of Industry, which is laid by Nature in strata of mineral Coal, whose amount is limited, and which, when once exhausted, is gone for ever. As the Law most justly interferes to prevent the wanton destruction of life and property, it should seem also to be its duty to prevent all needless waste of mineral fuel; since the exhaustion of this fuel would irrecoverably paralyze the industry of millions. The tenant of the soil may neglect, or cultivate his lands, and dispose of his produce, as caprice or interest may dictate; the surface of his fields is not consumed, but remains susceptible of tillage by his successor; had he the physical power to annihilate the Land, and thereby reflect an irremediable injury upon posterity, the legislature would justly interfere to prevent such destruction of the future resources of the nation. This highly favoured Country, has been enriched with mineral treasures in her strata of Coal, incomparably more precious than mines of silver or of gold. From these sustaining sources of industry and wealth let us help ourselves abundantly, and liberally enjoy these precious gifts of the Creator; but let us not abuse them, or by wilful neglect and wanton waste, destroy the foundations of the Industry of future Generations.

Might not an easy remedy for this evil be found in a Legislative enactment, that all Coals from the Ports of Northumberland and Durham, should be shipped in the state in which they come from the Pit, and forbidding by high penalties the screening of any Sea-borne Coals before thoy leave the port at which they are embarked. A law of this kind would at once terminate that ruinous competition among the Coal owners, which has urged them to vie with each other in the wasteful destruction of small Coal, in order to increase the Profits of the Coal Merchants, and gratify the preference for large Coals on the part of rich consumers; and would also afford the Public with a supply of Coals of every price and quality, which the use of the screen would enable him to accommodate to the demands of the various Classes of the Community.

A farther consideration of national Policy should prompt us to consider, how far the duty of supporting our commercial interest, and of husbanding the resources of posterity should permit us to allow any extensive exportation of Coal, from a densely peopled manufacturing country like dtui own; a large proportion of whose present wealth is founded on ma

« AnteriorContinuar »