exposed, might be very advantageous, since the labor of exploring is simple and expensive, nor does the water present any obstacle to the openings required for obtaining the coal. Nevertheless, when the covering strata contain in their lower portion impermeable stratifications like the dieves, especially when they are not too thick or carry too much water, the difficulties of sinking are largely compensated by the advantage that the miner is protected from a large portion of the water at the base of the chalk series, during all the period of this operation, however long that may be.

39. Of the waters in the coal strata.

The miner has no reason to apprehend in the coal strata any abundant springs, like those in the chalk formation. The beds of schist and the seams of coal furnish some rare infiltrations, which appear under the form of little streams or droppings escaping from the pores of the rock. But the sandstone, usually much fractured, and the clefts of which are very open, offers a passage to the water, very difficult to restrain and costly to drain. În general, the rule, or nature, of springs seems to be subject to one or the other of the following conditions; sometimes they dry up, after having been reduced by drainage, and do not appear again, or at least they do not show themselves again, except in very small quantity and at periods noted for heavy rains; sometimes they continue to discharge water with great uniformity; when such is the case, it is caused by some fissure operating as a canal from a great reservoir to the shaft, and furnishing the constant supply. In short, the waters of mines are generally more abundant the nearer the working approaches the surface, because the nearer they are to their source, so much less are the obstacles encountered by them in passing through the fissures of the strata.*

To be continued.

A series of chapters more immediately follows in the works of Ponson which are devoted to descriptions of the coal basins of Belgium, France, England, and Germany. As these are particulars not of immediate interest to the practical miner in this country, we propose to pass over them for the present, and commence next with "The method of searching for coal."-ED.

COALS AND COLLIERIES.

ANTHRACITE COAL TRADE FOR 1856.

Shipments by Reading Railroad to August 21st,

Schuylkill Canal,

The Scranton coal trade east towards New York, for July and to August 23d, will exceed 25,000 tons.

CUMBERLAND COAL TRADE.

Total shipped by each company from Januaray 1st to August 23d.

The increase of anthracite thrown into the market for the last five years reached 3,196,443, tons; 5 divided into this, would give the annual increase 630,286 tons. During two of these five years, the markets were completely cleaned out of coal, and prices ruled very high. For the last five years the increase of bituminous and semi-anthracite, including the foreign importations, destined for the Atlantic markets, reached 601,538 tons, which divided by 5 gives the annual increase at 188,307 tons.-Pottsville Jour.

COAL WHARVES AT TRENTON, N. J.

The method of unloading cars of coal by shutes into vessels is adopted in many places, varying only in such details as arise from local peculiarities. Those of our readers who have never witnessed this operation, will find the following sketch of the wharves at Trenton, of interest.

The Belvidere, Delaware Railroad crosses the Delaware and Raritan Canal, in the outskirts of the city of Trenton by a drawbridge, and curving towards New York, reaches the coal wharves with three tracks in about half a mile.

A basin is dug or obtained by widening on the berne side of the canal. This basin is now 1,200 feet long, is well wharfed in front, and wide enough for a light schooner to turn around clear of one that may be loading at the time.

The landing to receive the loaded coal cars consists of a heavy and well braced trestling parallel with the canal, and carrying mainly three tracks of rails-the deck of the landing being elevated 17 feet above water line, which being in a canal level, has the advantage of being invariable.

The play of the landing is the continuous packet system (with some stretches of flat floor dumping ground). The trestles, are 12 feet apart centres, and between each pair is a sloping pocket crossing three tracks, and open to dumpage from each. All these pockets terminate below in a schute with a wrought iron apron, managed by a winch on deck, and proceeded by a cast-iron screen, exactly like the Navigation Landings at Port Carbon, in the dirt-separating arrangement. From these pockets, the coal flows by gravity, into vessels.

Each pocket is estimated to contain about 50 tons of coal (or 400 tons

per 100 feet lineal of wharf), and in their ordinary work 200 tons per hour are loaded from them.

The aggregate wharf expenses are estimated at 4 to 5 cents per ton loaded, and the whole of the sinall screenings thus far, commands $1 50 per ton at the wharves, for a New York market.

The loaded cars are placed on the elevated deck of the landing by the following operation:-Up to within a quarter mile of the wharves, the tracks are level with the canal bank, then this quarter mile ascends by a single track on an incline (chiefly on trestling) at 1 in 50 or thereabouts, and the locomotive pushers employed, come up to this incline under headway gained on the level track, and with their cars before them, rush up the ascent, and place their loaded cars upon the deck tracks rapidly and without difficulty. The pusher working to-day, handled with ease 7 loaded cars, containing 35 tons of coal, at once, and she only had the adhesion of one pair of drivers. The large engines push up 100 tons of coal at once.

The depth of available draught water in the canal, is 6 feet. At present, barges load at these wharves with 300 tons of coal, and schooners for Providence and Boston, load with 200 tons.

All the coal handled here at present is Lehigh Coal, costing for transportation from Mauch Chunk and delivery on the wharves $2 00 per ton.

No difficulty whatever arises from the coal cars having wide treads upon the wheels, and working over both gauges of 4 feet 8 inches and of 4 feet 15 inches.

They are now shipping at their wharves about 2,500 tons a week, though this is very far within their capacity.

Boats and schooners loading here have about 25 cents a ton advantage in tolls over Richmond. The wharves admit of indefinite extension, and Trenton cannot fail to become a great coal mart, which can only be reached from Schuylkill County by the Allentown Railroad.

The general plan of these wharves and their continuous pockets, are almost a precise duplication of the Dauphin Coal wharves, designed and built by the late Mr. Morton, Civil Engineer, about ten years ago, at Dauphin, on the Susquehanna River.

The switches of the railroad, about here, have the fixed cast-iron guard of the Reading Railroad attached to the movable rail, so as to secure a train from leaving the track, in all positions of the switch rail.

The frogs are short, movable rails thrown by a switch lever.

Some of the tracks have " Trimble's wooden splice" outside of the joint, well secured to sills and rails, but they do not appear to be very successful, though properly applied.

MAN MACHINES.

This is the name given, in some parts of Europe, to the machinery which is used to raise the miners from the pits, in order to avoid the tedious ascent by ladders. The improvements in the various methods used for ascending and descending shafts, especially in coal mines, was very completely illustrated at the late French Exhibition. This information is too valuable to be lost, and we have collected it from some graphic letters of a correspondent of the Pottsville Journal, who was in Paris during the Exhibition. The latest improvements in use in European collieries are therein described:

In machinery connected with this department France leads off; following close upon her is Belgium. The praises and prizes with which imperial societies, in the first country, reward any successful inventions whose object is to render human life more safe, to prevent accidents, to ward off bodily injury from those poor (but not, in France, uncared for) classes, whose every

day business would seem to expose them to a risk equal to that encountered by the soldier who enlists for battle-have stimulated, to a wonderful extent, ingenuity having this for its object. Accordingly, we find no less than three machines for preventing that most fertile source of accident, the fall of the cages in the pits, from the breaking of the rope or chain by which they are raised and lowered.

The fall of the cages (with the workmen in them) is prevented by a most ingenious contrivance, which, like the safety-lamp and other great humanitarian inventions, is as remarkable for its simplicity as its efficacy. Whoever it be to whom the credit of this idea is to be given (I believe it is M. Machecourt, mining engineer at Decize collieries), he certainly deserves honor, second only to that of Sir Humphrey Davy, for the origination of so benevolent and effectual a plan for removing the terrors from this portion of the miner's daily risks, and rendering a ride up and down the shaft of a colliery as sure and pleasant as an ordinary one in a stage coach or a "Hansom Safety," above ground.

Accidents from the rupture of a chain, the breaking of a ring, an irregular winding upon the "drum," a careless oversight of the engineer in managing his wonderful but delicate power-all these have been occurring weekly if not daily in the collieries of Belgium, France, and England, with the loss of, now a single miner, now a cage-load, until humanity was aroused and cried out loudly for an amendment. As long ago as 1845, it would seem that M. Machecourt had introduced a contrivance which he styled a "Parachute" into his mines at Decize, by which, though the rope broke, the cage was suspended in the pit, and its load, if it happened to consist of flesh and bones, instead of coal, saved from certain death.

Though M. Machecourt took out no patent for this invention, and gave, as it appears, liberal publicity to it, very little notice seems to have been taken of it, and England, at least, has been going on in the old way of economy and butchery, for ten years, without the invention being regarded or even perhaps known of.

The principle of this "Parachute," for which M. Machecourt has been rewarded with medals by the "French Institute," is as much like that of one form I have seen of the ordinary "steam-engine governor," as can be. Without going into a particular description, which would take up more space than I have to devote to the subject, if your readers, the next time they see an engine, will just look at the "steam governor," and will imagine the balls on the ends of the two arms to be replaced by iron claws that resemble forks; and the rod that runs up from the top, instead of being used to open and shut valves for the admission or exclusion of steam from the boiler to the piston, to be fastened to the rope used in raising and lowering loads in a pit; and the whole concern to be attached to the cage in which the complement of coal or colliers is being dragged, by the power of steam, to the surface; they will be prepared to comprehend fully the action of the "Parachute."

Extending from top to bottom of the pit, on each side, is a wooden guide, always used in pits of any depth, to prevent the cage from swaying to and fro in its ascent or descent. Up these the cage slides, as the piston rod of an engine would glide along its guides. Arrived at a certain point, a terrible number of yards to look down from the top to the bottom, suppose the rope to break-perhaps the wind has blown the winds off the drum at the top, and a sudden jerk has snapped asunder the frail threads; or a pulley wheel has given way, contrary to everybody's expectations, and to the proprietor's deep regret;" or, to the endless surprise of the individual whose duty it is to look after it, and who never, under any consideration, neglects that duty, the iron ring which fastens the rope to the cage is suddenly ruptured; or, because it is more economical to use the old rope which has had the advantage of enjoying enough years of experience to grow rusty in the service, a month or two longer, rather than replace its threadbare fifty or a hundred or two