THE INDUSTRY OF ALL NATIONS.

crystallisations possess, however, far more interest for the chemist an mineralogistthan for the economist, who will see more hope of future returns to shareholdersin the lumps of solid galena, and the bars ofwhite silver, than in the brilliant facets of thegems before named.

The inexperienced in such matters will learnwith interest, however, that these flowers ofthe earth’s dark recesses have a high economi-cal value as indicating the existence of solidand enduring mineral wealth below. In thechemical and geological antagonism, whoseenergies sent up to the surface the mineralveins from the deep interior, the more volatileand easily exhaled compounds have sought theupper surface. The air and the atmosphericwaters also have penetrated to a certain depth,in the course of the veins, producing changesin their contents, the most remarkable of whichis the washing out and removal for the mostpart of the metallic substances. These veins,therefore, near the upper surface, present only adull mass of cellular quartz, whose cavities arefilled with yellow ochre, or dull black powdersof the oxyds of iron and manganese, with hereand there, perhaps, a metallic spangle, or stain.

The eye of the experienced miner rests withdelight on these ugly gozzam, as he calls them,in the provincial dialect of Cornwall—for heis sure of success in depth where the surfaceoffers such promise. Succeeding these dulland unattractive signs, of which Mr. Wheatley’scollection presents specimens, are found theelegant salts before mentioned, but lower downat the depth of some hundreds of feet, heavymasses of galena and of other sulphur com-pounds of the metals, fill the rich portions of

have it in our power to call public attention to this subject by so good an exampleof patient and skilful development at our own door. To give more distinctness to

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CONDENSING BEAM ENGINE, 24-INCJll CYLINDER, IN CSS AT CHARLESTON MINE.

the vein, and offer the safest assurance of continued wealth.

The geology of this metalliferous district of Pennsylvania, has been studiedlately by Prof. H. D. Rogers, who has made a special report to the proprietors upon

Hldl-PRESSURE PUMPING ENGINE, 24-INCn CYLINDER, IN USE AT BROOKDAI.E MINE.

it. Prom this report, and our personal knowledge of the district, we have drawnwhat has been said. The elaborate maps of the region, constructed upon the planof the ordnance sr; vey maps of Great Britain, will he observed, suspended in theExhibition, and upon them the metallic veins are traced in gold. We are happy to

88

the matter, we have caused some of the diagrams of the mining machinery,used at the Wheatley Mines, to be engraved for this article. Although suchdrawings may be of no special service to the experienced miner, they cannotfail to impress those who have had no previous knowledge of the subject withthe absurdity (not to say the criminal disregard of others’ interests), of those whorush ignorantly into the business of mining explorations, with no other idea thanthe creation of some temporary excitement, during which innocent persons are in-duced to subscribe shares, with the certainty of failure before them. In view ofthe unfortunate frequency of such examples, we hail with pleasure the exposi-tion of Mr. Wheatley as a tokens of some sure progress made in one of thegreat industrial and productive arts of this country.

The steam engines employed hitherto in this region are high-pressure en-gines, and they have been used alike for pumping and for raising the miningproducts to the surface. Hereafter as the resources of the region are more fullydeveloped, the much more economical Cornish engine will be employed. Onesuch machine is indeed already in motion at the Perkiomen Copper Mine withthe most satisfactory results. Below are given figures showing the construction,and position of the steam engines in use at the Wheatley, Brookdale andCharleston Mines. Also a tabular statement of the duty performed by each.

It will be observed that all these engines are automatic or intermittent intheir action, remaining inactive until a certain load of water has accumulatedthe pumps, when “ a float ” releases a lever communicating with the steam“ cut-off,” and a motion of the piston relieves the pumps of theirburden, and the machinery is again quiet until a fresh accumulation.The great economy of fuel, and of wear and tear in such an ar-rangement must he obvious, as compared with a regular continu-ous motion, having no regard to the work to be done.

This engine is situated on the same vein or lode as the “ Wheat-ley,” and is distant from it 2,076 feet in a southwesterly direction.It will be observed that this engine works upon the dip or “ under-lie ” of the vein, which is here about eighteen inches in a fathom.Between those two engines, at a point nearly midway, and on thesame vein, a very large shaft is now in process of being sunk, overwhich is to be placed a first-class Cornish engine, with the design ofdraining the entire lode. When this is accomplished, the enginesbefore described will be used only to raise the products of the mineto the surface. The proposed Cornish pumping engine is to have adiameter of cylinder of 80 inches, and a stroke of 12 feet.

About half a mile westward of the Wheatley and Brookdale Mines, whose engineshave just been described, exists another powerful silver-lead lode strictly parallelto the first named. This is called the Charleston vein. It has as.yet been ex-