The principal of these lines are the following: 1. The Schuylkill canal, which extends from Philadelphia to the vicinity of the mines about the head of the Schuylkill. Its length from Philadelphia to Port Carbon, is 108 miles; it cost, inclusive of the double locks, 3,000,000 dollars, or 28,000 dollars a mile, and yields a net income of 20 to 25 per cent.; 400,000 tons of coal are annually brought down upon it. 2. The Lehigh canal runs from the Delaware to the mines near the heads of the Lehigh; it is 46 miles long, and cost 1,560,000 dollars, or 34,000 dollars a mile. 3. The lateral canal along the Delaware starts from Easton, at the mouth of the Lehigh, and ends at Bristol, the head of navigation for sea-vessels. It transports to Philadelphia, the coal that is brought down the Lehigh canal; it is 60 miles long, and cost 1,238,000 dollars, or 20,600 dollars a mile. This work was executed by the State of Pennsylvania, and has been before enumerated among the State works. 4. The Morris canal starts from Easton, and ends at Jersey City, opposite New York. It serves to supply the New York market with coal. The change of level is here for the most part effected, not by locks, but by inclined planes, the operation of which is very simple; the length of this work is 102 miles, cost 2,650,000 dollars, or 25,000 dollars a mile. 5. The Delaware and Hudson canal extends from the Roundout creek on the Hudson, near Kingston, 90 miles above New York, to the anthracite mines near the upper Delaware. The coal is brought down to the canal, at Honesdale, from the mountains, at Carbondale, on a railroad 16 miles in length; the canal is 109 miles long, and cost 2,250,000 dollars or 20,000 dollars a mile; the railroad cost 300,000 dollars or 17,500 dollars a mile. 6. The Pottsville and Sunbury railroad is designed to bring down to the Schuylkill the products of the mines lying in the heart of the mountains between the Susquehanna and the heads of the Schuylkill. It is remarkable for the boldness of the inclined planes, some of which have an inclination of 25 and 33 per cent., and which are worked by very ingenious and economical contrivances. It is 45 miles in length, and cost 1,120,000 dollars, or 25,000 dollars a mile. 7. The Philadelphia and Reading railroad, now in progress, will enter into competition with the Schuylkill canal; it is 56 miles in length, and cost, including the necessary apparatus, 26,300 dollars a mile. It is proposed to continue it to Pottsville, 35 miles from Reading; there would then be a continuous railroad from Philadelphia to the centre of the Susquehanna valley.