THE Room, in this Case, will soon become suffocating, in the manner of a _German_ Stove Room, and does exactly point out the Difference between that Stove and mine. WHEREAS, on the contrary, when the Doors of the Room are shut, and the Register gives a proper Vent to the Fire, the warm Air, in this Case, is at Liberty to act as before, by warming the circumambient Air in its Passage from the Mantle-Piece to the Cieling, where it mixes slowly and imperceptibly with the grosser Air of the Room, which, in its turn, flows towards the Stove and Fire; part whereof feeds the Fire, and passes off with the Smoke; and the other part, after being rarified by the Heat of the Stove and Fire, ascends by the Mantle-piece to the Cieling, as it did before; repeating the like Circulation as long as there is any Heat in the Stove. By which it appears, that the warm Air that comes from the hot Iron Canal of the heated Air-Box, is sufficient to support the Fire, and carry off the Smoke, without the Assistance of any Air from the Crevices of the Doors and Windows of the Room. BY this Means, the Air in the Room is continually changed, and an Advantage gained that could never be obtained by any former Contrivance of the Kind; that at all Times the Air in the Room is as wholesome as the external Air; and, in some Respects, more so: For it is apparent, that the Air issuing into the Room through a hot Canal of Iron, can never acquire any noxious Quality; and, on the contrary, in damp Weather, when the Air is replete with Moisture, and noxious Particles, it will be purified in its Passage, and the Moisture and Vapours will be condensed, fall, and stick upon the Sides of the hot Canal. UPON this, as well as other Accounts, this Stove will be extremely useful in Hospitals, and the Rooms of sick Persons, with great Advantage to the Patients: But this I submit to those who are better qualified to judge of such Matters. _Fourthly_, IN Common Stoves and Chimnies, the upright Heat (which has been computed to be Three Fourths of the whole) is intirely lost, as to the Purpose of warming the Room, or those that are in it. On the contrary, in this Stove-Grate, a very inconsiderable part of the Heat ascends with the Smoke, and all the rest is diffused gradually, and equally, over the whole Room. _Fifthly_, THIS Fire-Place, thus prepared, prevents Smoke so effectually, and so certainly, in all Degrees and Variations of Wind and Weather, that the Inventor is willing to give his Machine, _Gratis_, if ever the least Smoke is perceived in any Room where it is erected; unless it may happen at the first lighting of the Fire, before the Air in the Funnel is put in Motion; but I have never yet seen that happen. THERE is no Occasion for Chimney-Boards in Summer, for by turning the Register, the Air is shut out; so that both in Summer and Winter, the Furniture and Gilding, is preserved from Smoke and damp Air; which are the chief Causes of the one and the other’s being spoiled.