58

FORM OF THE RETORTS FOR

longer fit for use than those of a cylindrical shape,an assertion of which subsequent trials, conductedin the manner just stated, lias clearly shown thefallacy. Enough has been done at the different gasworks in the capital to settle this point, and thereis now but one opinion amongst those who arebest qualified to judge of the subject. Every bodywho has made the trial on a large scale, is con-vinced as already stated, that the best form of theretort for manufacturing coal gas where the processis conducted on the plan of decomposing coal inmasses or layers of from four to eight inchesin thickness, is a cylinder six and a half feet long,and one foot in diameter, and accordingly retortsof this shape and dimensions are now used in allthe best regulated gas establishments in the me-tropolis.

A cylindrical retort of the description beforenamed, weighs about nine and a half to ten hun-dred weight. These and all other shaped retortsare furnished with a moveable lid or cover havinga conical edge to fit the mouth-piece ; the coveris rendered air-tight, not as formerly by grinding,