222

HEAT.

Above 320° the liquid sulphur again thickens, so that the evil would be increased.In use, the low temperature at which sulphur will inflame indicates the necessity ofgreat precaution in preventing the substances or machines with which it is broughtin contact from being over-heated.— Editors.

The subsequent Proof and Practice of Gunpowder appertains especially to theArtillery Service. In the ordinary process of manufacturing gunpowder abovedescribed, the practical results are f L. G. (large-grained) and £ F. G. (fine-grained);and this proportion fortuitously proved to be that of the average consumption in thelate wars England has been engaged in.*

The Construction of the Buildings of a Gunpowder Manufactory has hitherto beenprincipally of wood; but, besides that this material, when dry and seasoned, is ofitself combustible, experience has shewn that its pores, as well as the connection ofthe framing of the building, become so impregnated with the dust, and liable to thelodgement of particles of powder, as to be highly inflammable and explosive: andtherefore each building of wood is not only extremely liable to accident of thatnature, but the ignited materials of an exploded building extend the danger to allparts of the establishment.

To remedy such a dangerous mode of construction is a subject of much interest tothe Engineer Department; and it is suggested that the buildings be slight sheds ofthe best bricks, built with cement, having brick piers at the angles or jambs andto support the roof, which should be flat, with sides forming a shallow cistern, sothat any ignited matter falling on it would be extinguished. Some establishmentshave also small cisterns immediately over the powder undergoing the differentprocesses of manipulation, so that on any alarm the quantity in operation may beimmediately immersed by the person attending it. The building should be linedwith painted floor-cloth, a surface easily kept clean, and strong enough to preventaccidental damage from a blow, and less liable to degradation than plastering.

The buildings should be amply furnished with lightning conductors, and should heseparated as much as possible by earthen and chalk traverses, formed at an easyslope, and planted; and the manufactory grounds should he intersected by rows ofpoplars, or other trees, so as to afford natural impediments to the extension ofmischief from any partial explosion.—E. F.

H.

HEAT.f —Heat, in the ordinary application of the word, signifies, or rather impliesthe sensation experienced upon touching a body hotter, or of a higher temperature,than the part or parts which we bring into contact with it: in another sense, it isused to express the cause of that sensation. To avoid any ambiguity that may arisefrom this double use of the same expression, it is usual and proper to employ the word

t Compiled by Lieut.-Colonel Portlock.

See note by Editors.