In the case of the public arsenals, however, the saving from the employment of coal gas is a consideration of far inferior importance to the _superior security_ attending it. On the preservation of the stores which they contain may depend in a time of war the whole chance of success against the enemy nor can any body who has lived in this country at such a time have forgot the feverish alarm with which the people have frequently seen this security endangered by accidents arising from the use of moveable lights. Were coal gas exclusively employed in such establishments, the fixed position which can be given to the burners, and the absence of all danger from sparks must give a degree of security to those places from fire, far beyond what they at present possess, even when superintended with the greatest possible caution and fidelity. The same remark is equally applicable to the government offices, public libraries, museums, in short, to all public establishments where the national value of the articles preserved is such that no _possible_ means of increasing their security from destruction should be neglected. We have now to turn our attention to another general point of view in which the introduction of lighting by gas is not less an object of interest to the public; we allude to the application of gas as a means of _heating_ as well as lighting. Mr. Maiben[1] was the first who directed the attention of the public to this subject; he ascertained that gas from coal gives nearly the same heat when put into combustion, which is yielded by a third part of the coal from which it is extracted. In other words, it has been found that a quantity of fuel giving a particular degree of heat, may be employed so as to produce at the same time another substance yielding nearly an equal degree of heat in a different and more manageable form; a form in which it can be preserved for any length of time, divided into any portions, distributed in any direction, consumed in an open fire-place, or in a stove concealed in any shape; a form in which the flame may issue equally well from iron or from stone-ware, be instantly lighted up and instantly extinguished, be made to burn as long or as short a time as may suit us, and in any degree of intensity between the most animating and brilliant blaze and its total extinction; be extinguished in one room, and the next moment lighted up in any other; in short such a form, that by one proper arrangement from the beginning, with the same portion of fuel, we may at any time have the command of a chearful fire, an adequate and comfortable warmth in any part of our dwelling to which we may have occasion to move, as manageable, and in this way as portable, as the taper by the touch of which it is kindled. To those who have been accustomed to see before them a solid mass of burning fuel, this gas flame may at first have the less satisfactory appearance of a fugitive blaze which we perceive nothing to support.