Without increase of cost, then, we shall obtain a power which will insure a rapidity of internal communication far beyond the utmost speed of horses in draught; and although the performance of these carriages may not have hitherto attained this point, when once it has been established, that at equal speed we can use steam more cheaply in draught than horses, we may fairly anticipate that every day’s increased experience in the management of the engines, will induce greater skill, greater confidence, and greater speed.

The cheapness of the conveyance will probably be, for some time, a secondary consideration.  If, at present, it can be used as cheaply as horse power, the competition with the former modes of conveyance will first take place as to speed.  When once the superiority of steam-carriages shall have been fully established, competition will induce economy in the cost of working them.  The evidence, however, of Mr Macneill, shewing the greater efficiency, with diminished expenditure of fuel, by locomotive engines on railwavs, convinces the committee, that experience will soon teach a better construction of the engines, and a less costly mode of generating the requisite supply of steam.

Nor are the advantages of steam-power confined to the greater velocitv attained, or to its greater cheapness than horse-draught.  In the latter, danger is increased, in as large a proportion as expense, by greater speed.  In steam-power, on the contrary, ’there is no danger of being run away with, and that of being overturned is greatly diminished.  It is difficult to control four such horses as can draw a heavy carriage ten miles per hour, in case they are frightened, or choose to run away; and for quick travelling they must be kept in that state of courage, that they are always inclined for running away, particularly down hills, and at sharp turns of the road.  In steam, however, there is little corresponding danger, being perfectly controllable, and capable of exerting its power in reverse in going down hills., Every witness examined has given the fullest and most satisfactory evidence of the perfect control which the conductor has over the movement of the carriage.  With the slightest exertion it can be stopped or turned, under circumstances where horses would be totally unmanageable.

338.  Another instance may be mentioned in which the object to be obtained is so important, that although it might be rarely wanted, yet machinery for that purpose would justify considerable expense.  A vessel to contain men, and to be navigated at some distance below the surface of the sea, would, in many circumstances, be almost invaluable.  Such a vessel, evidently, could not be propelled by any engine requiring the aid of fire.  If, however, by condensing air into a liquid, and carrying it in that state, a propelling power could be procured sufficient for moving the vessel through a considerable space, the expense would scarcely render its occasional employment impossible.(3*)