adapted to mining purposes, which include pumping, winding, stamping, and crushing, they would be likely to render great service to the mining interest of this county. Referring to a paper of mine on the rise and progress of the Cornish steamengine, which was published in the Mining Journal of 1st July last, I there noticed the great danger of working the long-stroke single cylinder pumping-engines highly expansive, at least, as they are now generally constructed. Since that time a very destructive accident has occurred to one of the first-rate singlepower engines of 12 feet stroke, in which the expansion principle of steam power has been carried to a greater extent than was ever before attempted in this county in a single-cylinder engine, and in which the economy of fuel by working on that principle has been fully proved, by the duty of the engine being much above any other engine which has appeared on the monthly report. But although the economy of fuel has been so great, there has been a sad contrast in the economy of material, plainly showing that it is by no means safe to work so highly expansive with the present general construction of the steam pumping-engine. In this accident to which I have referred the piston-rod first broke, or rather was pulled asunder, and at the same instant broke the cylinder, steam-case, piston, and cylinder bottom. Of course the working of the engine was suspended for many days, and the loss to the mine was immense. I think this accident alone (although it is only one of a great many which have come under my notice) is quite enough to show that if the economy of mining is to be assisted by working such powerful engines so highly expansive, the construction of the engine should be more suitable to that mode of working. The direct-acting engine is, I think, rather better as regards safety; but there is an objection to it, in consequence of the cylinder being fixed over the shaft, which causes it to incommode the necessary operations. The inverted engine is, I think, much better. This engine has the main beam below the cylinder, therefore the effect of working expansive on the piston-rod and main connection is reversed thereby rendering the engine safe so far as regards these things if working at the highest rate of expansion. The economy of this engine may be otherwise reckoned as follows: 1st, in price from the manufacturer; 2nd, in the saving of masonry and carpentry work; 3rd, in time and cost of erection; and 4th, in the very much less liability to accident. Judging from the engines that are at work on this plan, I am quite satisfied that this mode of working the Cornish single-cylinder pumping-engine is highly important in point of economy, and I would therefore particularly beg to call the attention of engineers and others to the fact.

Respecting all rotatory engines for winding, stamping, &c., I would recommend their being horizontal; they are equally efficient as regards power and duty, and of course the economy

of laying them down in this way must be very evident. I have paid particular attention to those that are working in this way, and I have not yet been able to discover a single objection to them. For stamping-engines, where a great number of heads are required, say one hundred, I recommend having two engines instead of one as now used. The reasons for this arrangement are obvious, with two engines there is little chance of there being more than one half the heads idle at a time, but with one engine the slightest accident will cause the whole to be idle.

Small portable engines for the purpose of examining lodes to a limited depth would, I think, add considerably to the economy of mining. It has been a practice which, I believe, began with the commencement of mining in this county,-namely, that of bringing forth an adit level to the lode from some considerable distance, where the surface is much below the surface of where the lode is discovered, probably varying in depth from 5 to 50 fathoms; some are completed in a few months, others take years to accomplish, and at an immense cost. I have known £5,000 spent in such thing, and after all the time and expense, the lode (as many others) turned out to be worth nothing. Instead of all this, if a small portable engine were employed, the lode could be seen equally deep if necessary, and in a time and at an expense bearing no comparison to that of the adit or level. The engine (provided the fode turned out well) might be substituted by a much larger one if necessary, and the small engine applied for winding or stamping; if, on the contrary, the lode should not turn out productive, the engine would no doubt be soon disposed of for a like purpose, whereas the expensive adit would be by no means saleable. I would remark, that if the lode should turn out well, then it might be found to be the interest of the proprietors to make an adit; but I do think that the continuation of this plan of ancient mining, before knowing whether or not it would be useful, and in the face of the great economy of steam power, is a considerable drawback from the great credit attached to the Cornish miner. Respecting the supply of materials to the mines, I believe competition has reduced them as regards price to almost the lowest point of economy; but judging from the very inferior quality I have observed in some of the articles, it would be much to the interest of the adventurers that at every meeting there should be a written report of their quality furnished by the storekeeper, stating the price, from whom received, &c.

In the article grease for pistons and stuffing-boxes of steamengines, the best tallow is cheapest, as there is frequently in the low-priced grease some very destructive quality, probably some acid, which, if not soon detected, injures the cylinders and pistonrods very rapidly. It first shows itself by decomposition of the softer parts of the piston-rod, and which is seen by a whiteness of the parts affected, and being rough to the touch, almost as if

filed; the cylinder also becomes rough on the inside, destroys the packing, admits the steam through, which adds to the destruction of the cylinder, until at length, as I have seen in two or three instances, the inefficiency of the engine to perform her work is effected. The best means I have known to restore the engine to her original state is to put in some very rough sand, or rather gravel, with the packing of piston, and with a small portion of black lead, together with some best tallow. The gravel scours the cylinder; the black lead, assisted by the tallow, fills up all little crevices, and together soon restore the cylinder to a proper working state. For the rod, some fine sand with the packing is best. In some cases, before the thing became so well known, the loss to some of the mines, by means of the water being in the bottom levels, by the frequent stoppage of the engine to pack the piston and stuffing-box, together with the loss of fuel, hemp, &c., has been immense.

I have certainly spun this epistle to a greater length than I intended, but as there are some important matters mentioned here, however imperfect my suggestions may be respecting them, if any part of these suggestions should in any way benefit the present position of the poor starving miner, and at the same time in some measure economise the present system of mining, it will afford me very great pleasure. That there will be many objections to the mode in which I have proposed to employ the miner, instead of the present by contract, I fully anticipate; but I do say that the miner in the present day is not in a position to take contracts; and that the great evils attending these things are more than are generally thought of, there can be little doubt; amongst which I would name some of the most prominent :1st, the cutting-down system, as it is termed, i. e. taking a tutwork contract at a farthing per fathom, or a tribute contract at a farthing in the pound. Sometimes this arises from some misunderstanding amongst the miners, and is therefore done through revenge; or sometimes to get into a steady place to work, taking the chance of a loan from the mine to support them, or probably having credit from some shopkeeper, or having the means of support in their possession. Now I would ask what quantity of work can it be expected men will do when they get nothing for it, and are obliged to pay the cost of the tools they use? This, certainly, does not look like economy in mining. 2nd, the lending system to miners,—namely, granting them a loan from the mine, when they have little or nothing to receive for work done; the effect of this is, that some worthless men (who I am happy to say are not very numerous amongst Cornish miners) will scarcely do any work, and, after getting considerably in debt, they leave the mine and debt also behind them.

It may be urged that the present system gives every man a chance of having work ;-granted; but it does not give to every

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one the means of purchasing the necessaries of life. It certainly admits any man into the mine, no matter whether or not he be capable of performing his contract; and I would beg, therefore, to put it to the good sense of adventurers and agents of mines,— which would be most economical for the mining interest, to make choice of men, and give them fixed wages with overseers, as before suggested; or to carry on the present system of contracts, thereby admitting, very frequently, a worthless class of men to take a like portion in the earnings of (I have no hesitation in saying) the best class of working men that have ever come under my notice, namely, the steady, industrious, and generally wellconducted Cornish miner.

ON THE PRACTICAL APPLICATIONS AND GENERAL INTEREST OF GEOLOGICAL SCIENCE.

BY THOMAS

SOPWITH, ESQ., F.R.S., F.G.S., C.E.,

Of Newcastle-on-Tyne and Allenheads.

[The following extract from the concluding portion of a series of Lectures, illustrated by diagrams, models, &c., given on the completion of the restoration of Crosby Hall, by the gentleman whose name is prefixed, conveys an epitome of many of the subjects noticed, at the same time that it presents a useful view of the practical character of geological studies; while we avail ourselves of this opportunity of expressing our obligations for the assistance afforded by Mr. Sopwith in the compilation of the present work.]

WHETHER We contemplate the phenomena of nature or the commercial transactions and domestic comforts of mankind, we shall find them all more or less interwoven with and dependent on geological conditions. The elevation of land above the sea, and the formation of mountain-chains by subterranean convulsions, determine in most instances the limits of kingdoms. The air and climate of every country are greatly modified by geological structure-by the greater or less area and elevation of landby the facilities for natural drainage, and the direction of currents of air. The supply of water eminently depends on conditions of geological structure as regards the relative position of pervious or impervious strata; and upon the abundance and quality of rocks employed for building purposes depend the stability, comfort, and duration, alike of public buildings and private dwellings. The goodness of our streets and roads-the

ON THE APPLICATION OF GEOLOGICAL SCIENCE.

131 navigation of our rivers the safety of our harbours-the right cultivation of the soil-all have an immediate relation to the general geological structure of each district, and to the judicious application of mineral products to the several purposes for which they were destined; and still more obvious and more important is the bearing of geological researches on national economy and national wealth. "If this inquiry," says Dr. Buckland, "should be extended through the endless departments of art, industry, and commerce, which have their origin in the manufactures of metals and in the power of steam, derived exclusively from the application of coal, the vast national importance of mineral statistics and of models-maps and sections, on which alone their details can be effectually recorded-must be apparent to every one." The study of the practical applications of geology is more or less within the reach of every one, and every one is deeply interested in this department of knowledge. Great facilities exist even in the metropolis for such studies, which will often be found closely connected with other branches of philosophical research. The beautiful fossils by which different strata are characterized at once gratify the curiosity of youth and present still greater attractions to more matured observation. The notion which many persons entertain of geology being an abstruse and difficult study vanishes before a moderate share of reading and observation. On the contrary, it is a study always at hand, ever soliciting attention, and ever, when attended to, conferring that delight which God has bestowed as a rich reward for the study of His works, and for the peace of mind and true nobility of thought which such pursuits inevitably cherish. The lessons of economic geology meet us in the crowded streets of the town as well as in the lonely valley of the country. A pebble tells of past revolutions of the earth with eloquence as impressive as the boldest cliff or loftiest mountain. The very soil, as we travel across the kingdom, often pictures forth as clear an index to the rocks beneath as do the vivid tints of an artificial map. The landscape-painter, acquainted with the elements of geological structure, observes and delineates characteristic features which escape the untutored eye. The columnar basalt, for instance, is as different in its aspect from broad and massive sandstone strata as the tall columns of Gothic architecture vary from the severe breadth of the Grecian Doric. Guided by the kindred studies of chemistry and geology, the farmer adds new value by giving increased fertility to his land. The architect endues his works with the power of duration by the proper and scientific selection of materials. The sculptor rivals the classic artist in the hardness of material as well as in delicacy of execution; and guided by these useful aids, the miner enters with confident and untiring zeal upon the prudent explorations of those hidden treasures which form the solid foundations of our national wealth.