30 



ANNUAL OF SCIENTIFIC DISCOVERY. 



ment of the progress of railwa}'S in the United States, from 1830 to 

 1851, which, with a correction or two, we here subjoin : 



Years. 



1830 

 1831 



1832 

 1833 

 1834 

 1835 

 1836 

 1837 



Miles. 



. 3,518 

 . 3,885 

 . 4,369 

 . 4,574 

 . 5,583 

 . 6,783 

 .11,471 



The Baltimore and Ohio Railway was opened a distance of thirteen 

 miles December 28, 1829 ; the South Carolina Railway, a distance of 

 six miles, November 1, 1830; the Lake Ponchartrain, April 16; the 

 Carnden and Amboy, a distance of seven miles, July 1st ; and the 

 Mohawk and Hudson, throughout, September 24th, 1831. 



It is difficult to prepare a table, which, when published, will give the 

 precise number of miles of railways in operation, as every day adds to 

 the number, and swells the grand total of miles completed or in operation. 



NAVIGATION AND SHIP-BUILDING IN THE UNITED STATES. 



THE following statistics of the foreign and inland commerce of the 

 United States, are derived from the report of the Secretary of the 

 Treasury, for 1850. In 1815 the tonnage of foreign shipping was 

 854,254 tons; of inland navigation tonnage, 513,813 tons. In 1850 

 the foreign tonnage had arisen to 1,585,711 tons, and the inland ton- 

 nage to 1,949,743. In 1815 the foreign tonnage exceeded the inland 

 60 per cent. Now the inland exceeds the foreign 25 per cent ! The 

 " registered tonnage " has increased 700,000 tons ; but the " enrolled 

 and licensed " tonnage has increased 1,400,000 tons. The whole in- 

 crease from 1820 to 1850, (a period of thirty years,) is 175 per cent. 

 Now the growth of population in that period is 130 per cent., proving 

 the growth of commerce and navigation to be faster than that of the 

 people. Among the most obvious causes of this fact is the introduc- 

 tion of steam navigation on the western rivers. The steam tonnage on 

 all the western rivers exceeds 300,000 tons ; but this had no existence 

 in 1815, the period of comparison in the above table. 



THE "WAVE" PRINCIPLE OF MARINE ARCHITECTURE. 



THE term " wave principle," often used, is little understood, except 

 by those Avho have studied naval architecture as a science, although 

 all the fastest ships, whether propelled by sails or steam, have adopted 

 the principle. According to the old principle, it was considered that 

 vessels should be built with the water line nearly straight, the run of 

 the vessel a fine line, and that there never should be a hollow line, 

 except a little in the run of the ship, and that there should on no 

 account be any hollow line in the bow, but that the water lines should 

 be either straight, or rather convex. Some years ago, at the request of 

 the British Association for the Promotion of Science, Mr. Scott Russell 



