The ventilation of coal mines was found to be a subject of considerable difficulty, until the invention of the safety lamp by Sir Humphrey Davy, tended, in a great measure, to prevent the danger springing from subterranean explosions. It seems to be admitted that the moral condition of the mining population of our country, who are employed in the coal trade, is good, and, as a class, they enjoy health. They are principally from England and Wales, with a few Irish and Scotchmen. Each miner, in the subterranean darkness of the mines, carries a lamp hooked to his cap. They wear heavy coarse shoes, covered with tacks, and while pursuing their labors, their rude clothes become saturated with coal-dust, and are made damp by the moisture of the mines, the floors of which are commonly covered with coal, mud, and water. Their wages, since the year 1831, have generally averaged a dollar each day, and, as a class, they may be deemed comparatively prosperous, and much attached to their mode of life.

We subjoin the following table, showing the prices of coal in the principal cities, from 1838 to 1848:→

AVERAGE PRICES OF ANTHRACITE IN NEW YORK, BOSTON, AND PHILADELPHIA.

The system of canals and railroads connected with the anthracite mines, is of some interest, as exhibiting the avenues through which these products are conveyed to market, and we accordingly subjoin the following table, exhibiting their number and extent:—

CANAL AND RAILROAD SYSTEM IN RELATION TO THE ANTHRACITE DISTRICTS OF PENNSYLVANIA, Canals. Railroads, Total cost. Mites. Miles,

Names of railroad and canals.

Lehigh Navigation ....

Lehigh and Susquehanna Railroad.

Mauch Chunk and Summit Railroads.

Delaware Division of the Pennsylvania Canal

Beaver Meadow Railroad

Hazleton Railroad

Buck Mountain Railroad..

Summit Railroal.....

Delaware and Hudson Canal-partly in New Jersey,

108

1,350,000

831,684 1,734,958

360,000

10

120,000

4

40,000

20,000

16

3,250,000

Morris Coal Canal, in New Jersey..

The Schuylkill Navigation....

The Reading and Pottsville Railroad..

Little Schuylkill and Tamaqua Railroad..

Mine Hill and Schuylkill Haven, and extension to Swatara.

CANAL AND RAILROAD SYSTEM-CONTINUED.

Name of railroads and canals.

Canals. Railroads. Total cost.
Miles. Miles.

A

There are many private railroads constructed since the above was drawn up. The whole may be estimated at more than forty millions of dollars. The northern region of the anthracite coal field of Pennsylvania, embracing the districts of Lackawana and Wyoming, is one of picturesque beauty, which has been portrayed in the fictions of poetry, and painted in glowing colors upon the canvass. It is a region of mountains and valleys, of crags, precipices, rivers, forests, and waterfalls. The Susquehanna winds its way through fertile plains, and sweeps the bases of mountains, which, although in some parts barren, repose like blue clouds upon the distant horizon. It moreover abounds in most valuable beds of coal, which have been but partially developed, but which are situated favorably for the exportation of their products to convenient markets. The principal avenue for the exportation of coal from the Lackawana anthracite region in the northern coal field, is by a railroad running eighteen miles, and the Delaware and Hudson Canal, extending one hundred and eight miles, to Rondout, upon the Hudson River. A navigation of ninety-one miles upon this river, reaches from that point to the city of New York. Carbondale constitutes the principal working point in the Lackawana region, where there was but one solitary house in 1829, but which contained in 1840 a population of two thousand three hundred and ninety-eight persons, who were mainly employed by the company in the enterprise of the coal trade.

The valley of the Schuylkill now constitutes, however, the main theatre of the anthracite coal trade, and the works connected with the Schuylkill navigation are of great importance. The Reading Railroad constitutes the principal outlet of this part of the anthracite coal region, and it is composed of two continuous tracks, extending ninety-three miles, from Mount Carbon, near Pottsville, to Port Richmond, upon the Delaware River, with a diverging track to the principal business street of Philadelphia, for the supply of the city. Richmond, however, constitutes the principal terminus of the road, and here are erected the most extensive works of the company for the deposit and shipment of coal. This place is situated upon the borders of Philadelphia, and about three miles from the center of the city. The wharves and works of the company occupy about forty-nine acres, and, as we are informed, are probably the most extensive and commodious in the world, being accessible to vessels of 700 tons burthen. The shipping arrangements are composed of seventeen wharves, which extend into the river, and furnished with chutes, through which coal is slid into the vessel lying near the wharf from the bottom of the coal-car in which it left the mine. Capacious docks likewise extend in shore, between each pair of wharves, and ninety-seven vessels can be here laden at the same time. The elevation of the tracks above the flooring of the piers, affords sufficient room for stowing 195,000 tons of coal. We are enabled to judge the amount of transportation upon this railroad, when we learn that the running machinery employed upon it is constituted of seventy-one locomotive engines, three thousand and twenty iron cars, fifteen hundred and thirty-nine wooden coal cars, which sometimes

appear upon the railroad in trains of a hundred, four hundred and eightytwo cars for merchandise, and use of wood, and seventeen cars for passengers. There is here also an engine house erected, the front supported by clustered pillars of cast iron, capable of containing twenty engines and their tenders; and, adjoining to this, a spacious machine and work shops have been constructed. Having exhibited the prominent facts connected with the of the anthracite coal trade, we subjoin the following table, showing its advance in the amount sent from the several districts, from the commencement of the trade in 1820, down to the close of the year 1848:

progress

TABLE SHOWING THE QUANTITY OF COAL SENT TO MARKET ANNUALLY, FROM ITS COMMENCEMENT, IN 1820, TO 1848, INCLUSIVE-PREPARED FROM OFFICIAL DOCUMENTS.

Pine

Lyken's

Years.

Tons.

Tons.

Tons. Tons.

Total Inc'se & Lehigh. Schuylkill. Lackaw'na. Grove. Valley. Sh'mokin. Wyom'g. supply. decrease. Tons. Tons. Tons.

Tons.

Tons.

Total.. 5,505,327 11,859,150 3,392,572 384,625 36,905 124,856 1,113,565 22,417,000

Of the coal brought from the Schuylkill Mines, the following quantities have been brought down on the railroad, the balance, of course, by the Schuylkill Canal:

The total supplies sent from the Schuylkill region, on the railroad and canal, in 1848, have been :

Pottsville..

Port Carbon....

Schuylkill Haven..

Port Clinton...

Total......

By Railroad.

By Canal. 257,706.19

Total supply.

Amount of coal left on the line of the canal above Philadelphia, in 1848... by the railroad, short of Richmond.....

66

........

70,525 178,610

Total tons

249,135

• Decrease.

+ Great freshet which injured the canal.

Less Shamokin mines.

From the above statement, it will be seen that the total quantity of coal sent to market from the commencement of the trade, has been 22,417,000 tons. Of this quantity the Schuylkill region has furnished 11,859,150 tons; the Lehigh, 5,050,327 tons; the Lackawana, 3,392,572 tons; the Wyoming, 1,113,565 tons; the Pine Grove, 384,625 tons; the Shamokin, (less 1848,) 124,856 tons; the Lyken's Valley, 36,905 tons.

The importation of foreign coal into the United States has been, moreover, considerable. The duty, within the last two years, has been one dollar and seventy-five cents a ton, and it has been customary, quite lately, since the trade in breadstuffs between our own country and Europe has been increased, to substitute coal as ballast, upon their route home. Subjoined is a table, showing the importations of foreign coal into the United States in tons, of twenty-eight bushels each, from the 30th of June, 1821, to the same period in 1847, which has been obtained from public documents in the city of Washington:

The following table shows the imports of foreign coal into the United States annually, from 1821, to the 1st July, 1848. The duty on foreign coal, under the present tariff, is 30 to 45 cents per ton, on board:

In July, 1789, a law was passed laying a duty of 2 cents per Lushel on imported coal. In 1790, the duty was increased to 3 cents. In 1792, the duty was increased to 4 cents; and in 1794, to 5 cents per bushel. This duty was continued until 1816, when it was changed to 5 cents per heaped bushel. In 1824, the duty was increased to $1 50 per ton. In 1832, the duty was raised to $1 75 per ton, which was continued until the present tariff, in 1846, reduced it to from 30 to 45 cents per ton.

The coal trade for 1849 will show a considerable increase over that of 1848. A satisfactory arrangement has been entered into between the railroad company and the Schuylkill Canal, in reference to the charges for toll on coal, which will prove advantageous to all those who have made investments in the stock of these companies.

It has been our design to exhibit the prominent facts connected with the enterprise which is employed in the coal trade of the United States. The mines of coal and iron have been one of the principal sources of wealth and power of Great Britain-a power which now girdles the globe, and unfurls its red banner upon the waves of every sea. Of the present extent, and growing importance of the trade, we are enabled to judge, as well from the actual returns, as from the vast amount which is consumed in the eastern cities for domestic purposes, and in the numerous boats which ply upon the waters of the country. It is supposed that our twenty millions of people

consume annually about five millions of tons of coal. There is now scarcely a depot of business that does not contain deposits of this mineral, which are employed either for manufacturing purposes, or in the carrying trade. There will, moreover, doubtless be an increased consumption, both of the anthracite and bituminous species, in the numerous iron works which exist in various parts of the land, in the enterprises of ocean steam navigation, as well as in the general progress of settlement and trade. This consumption will be, doubtless, augmented both at the East and West, in proportion as the value of this mineral is known, and the forests become exhausted.

Art. III.-THE HELIX: CONSIDERED AS A PROPELLER OF STEAM VESSELS.

FUNDAMENTAL QUESTION OF OCEAN STEAM NAVIGATION-REMARKS ON THE SCREW PROPELLERS— THEORY OF THE HELIX-CASE OF A HELIX EMPLOYED AS A PROPELLER-PRACTICAL REMARKSDIFFERENCE BETWEEN A HELIX AND A PADDLE-WHEEL PROPELLER-CONCLUSION.

OCEAN steam navigation requires vessels equally tremendous by their tonnage, steam-power, consumption of fuel, and, above all, by their costs. Altogether, these vessels, besides their own enormous weight, and stock of coal, transport nothing, being almost unfit for carrying anything else but the mere trifles of a mail and passengers' packet.

The whole destiny of this new mode of maritime intercourse is, then, still depending upon the means by which more suitable proportions might be introduced between the size and expenses required on one hand by, and the services and receipts expected on the other from, a steamship.

The huge and entirely disproportionate vessels actually in use, are imposed by a necessity which experience has rendered more irresistible, from day to day. The laws of this necessity must show the remedy to an increase which most probably has not yet, even in the largest ocean steamers, attained to its natural and dreadful bounds.

The matter will continually call attention to the common law of motion for a vertical plane, advancing by the line of its perpendicular axis, through an indefinite mass of water, which law, one second being the unit of time, A the area, V the speed, and the resistance of the medium, gives

V2 64,2882

quantity of motion of the plane.

A X V3
64,2882

FUNDAMENTAL QUESTION OF OCEAN STEAM NAVIGATION.

for the

Long sea voyages, which are to be performed by means of steam-vessels, present a question, which arises seldom or never with steam navigation applied only to short coasting travels, rivers, lakes, or inland waters in general. Each steam vessel must carry on board a certain provision of fuel. If this provision has to be large enough for providing, during a certain number of days, to the consumption of the steam-engine, it rises, naturally, to an amount which may require that the tonnage necessary for such a stock of fuel, the engines and their boilers shall be first taken into consideration. The whole tonnage of the vessel having to be equal at least to this, and to that of the stores for the crew and passengers. Hence arises the following fundamental question:-

What is the minimum of tonnage required in a steamship, so that the