[196] The general dimensions of these celebrated steamers were: length of keel, 277 feet; length on main deck, 282 feet; depth from the maindeck, 24 feet; depth under the spar deck, 32 feet; breadth of beam, 45 feet. They had rounded sterns, three masts with suitable spars; a lower deck, main deck, and spar deck, as well as an orlop deck extending from the engine-room forward and aft. The area of transverse section of the _Arctic_, for instance, was 772 square feet. Launching draught aft, 10 feet; average displacement per inch, from launching to load line, 20½ tons; area of load line, 9369·10 square feet; whole displacement to its circumscribing parallelopipedon, 601 per cent.; weight of hull, 1525 tons; weight of spars and rigging, 34 tons; ordinary load line aft, 20 feet; ordinary load line forward, 19½ feet. [197] I have not room for these very valuable historical documents, so much wanted in our own merchant navy, but the reader interested will find them _in extenso_ in note, Appendix O, in Mr. C. B. Stuart’s work, “On Naval and Mail Steamers;” U.S., published in New York, 1853. [198] A description in detail of these boilers is given in the note, Appendix O, already mentioned. [199] The respective diameters of wheels in these steamers from outside to outside of floats, were as follows, viz., _Arctic_, 35 feet 6 inches; _Baltic_, 36 feet; _Atlantic_, 35 feet; and _Pacific_, 35 feet. Those of the _Arctic_ and _Atlantic_ had thirty-six floats; the _Baltic_, thirty-two; and the _Pacific_, twenty-eight. The average performances of the engines of the _Arctic_ were as follows: pressure, 16·9 pounds; revolutions, 15·8 per minute with an average consumption of 83 tons of anthracite coals per day of twenty-four hours, giving an average speed of 316·4 knots per day. Her maximum pressure was 17·5 pounds; revolutions, 16·7 per minute; consumption, 87 tons, and speed 320 knots per day. The consumption of coal per day in the _Asia_ (Cunard line) was, on an average, 76 tons, and her speed with this consumption 303 knots per day. [200] The plates of this splendid engine will be found in the second volume of Tredgold’s “Steam-Engine,” and well deserve the attention of professional readers. Mr. Victor Beaumont’s account of the ship and engine will be found in the same volume. [201] See Reports of Proceedings in Congress. [202] The comparative cost of driving a steamer on the average of 7 knots up to an average of 9 knots is very small compared to what it would be to increase the speed from 9 to 11 knots an hour, and it becomes enormous when that rate is increased (as the resistance increases with the square of the velocity), but my readers must take the very large sum mentioned as the extra cost of one extra day’s saving of time with _very considerable qualifications_, as the statement was made in Congress with the object of obtaining for the Collins line further assistance either in the shape of a vote of money or an enhanced annual subsidy.