Again the constant supply of a sufficiency of water to the boiler is secured by an equally simple provision, namely, by a _float_ resting on the surface of the water which, as soon as it is carried down by the consumption of the water to a certain point opens a valve and admits more. And so on through all the different parts of the apparatus, the various wonders of which cannot be better summed up than in the forcible and graphic language of a recent writer:--“In the present perfect state of the engine it appears a thing almost endowed with intelligence. It regulates, with perfect accuracy and uniformity, the _number of its strokes_ in a given time, _counting_, or _recording_ them moreover, to tell how much work it has done, as a clock records the beats of its pendulum; it regulates the _quantity of steam_ admitted to work; the _briskness of the fire_; the _supply of water_ to the boiler; the _supply of coals_ to the fire; it _opens and shuts its valves_ with absolute precision as to time and manner; it _oils its joints_; it _takes out any air_ which may accidentally enter into parts which should be vacuous; and when any thing goes wrong, which it cannot of itself rectify, it _warns its attendants_ by ringing a bell; yet, with all these talents and qualities, and even when exerting the power of six hundred horses, it is obedient to the hand of a child; its aliment is coal, wood, charcoal, or other combustible--it consumes none when idle--it never tires, and wants no sleep; it is not subject to malady when originally well made, and only refuses to work when worn out with age; it is equally active in all climates, and will do work of any kind; it is a water-pumper, a miner, a sailor, a cotton-spinner, a weaver, a blacksmith, a miller, &c., &c.; and a small engine, in the character of a _steam pony_, may be seen dragging after it on a rail-road a hundred tons of merchandise, or a regiment of soldiers, with greater speed than that of the fleetest coaches. It is the king of machines, and a permanent realisation of the _Genii_ of Eastern fable, whose supernatural powers were occasionally at the command of man.”