Part 2
THE Doors, indeed, ought to be kept shut; because otherwise the warm Air will be wasted, as with common Fires; but there is no manner of Occasion for Skreens of any sort, because the Fire cannot hurt the Face; neither can the cold Air offend the Back, as in common Rooms, where there is a common Stove-Grate, and a large Draught up the Chimney.
_Thirdly_, TO be soon and agreeably warmed, is not the only Advantage we have from this Invention; but we are better warmed, at less than one Third of the usual Expence, at a moderate Computation. When the Mercury in my Thermometer, that was placed without Doors, stood the last Winter at Four Degrees below the Freezing Point, a Peck of Coals (_i. e._ the 144th Part of a Chaldron,) was sufficient to warm the Room for the whole Day, from Eight in the Morning to Eleven at Night. During all that Time the Mercury within the Room stood from 60 to 64 Degrees; much the same Degree of Heat with that of the 25th Day of last _June_, 1752, at Two o’Clock in the Afternoon; and, when that Observation was made, the Weather was as warm as usual at that Time of the Year.
BUT before I set up this Stove, which is one of the smallest, there was seldom spent, in the Room, less than a Bushel of Coals, and sometimes more, in one Day, according to the Degree of Cold; and then we were obliged to have a Skreen to keep off the cold Air from the Backs of those who sat near the Fire; and only that Part of the Room was warm which was nearest the Fire.
THE Air that enters the Room, through the Iron Canal of the Air-Box, is both fresh and warm; and computing the Swiftness of its Motion with the Area of its Passage, it will appear, that Ten Barrels, or near 60 Cubic Feet of Air is hourly introduced from the external Air, if the Door of the Room be shut.
THIS warm Air comes into the Room with such Rapidity from the hot Iron Canal, that it turns several Paper Wheels with great Velocity, which are placed near the Opening that lets it into the Room. But as soon as the Door of the Room is opened, all the Wheels stand still; which proves what has been said before, That much warm Air is wasted in opening the Door; because the warm, or rarified Air, rushes through the cold Air with great Force: And the cold Air that comes in at the Door, being an over-balance to the Air entering from the hot Iron Canal of the Stove, entirely stops it from coming into the Room while the Door is open.
IN like manner, if the Door of the Room be shut, and the Register that is fixed in the Smoke-Passage be turned so near as almost to shut it up, which may be done when the Coals upon the Fire are burnt to a Coke, then the whole Heat of the Fire will be forced into the Room, the warm Air will be stopt from coming through the hot Canal, and the Paper Wheels will stand still, as they did when the Door of the Room was open.
THIS may seem a little unaccountable, but, when considered, it is plain, that the warm Air from the hot Canal cannot come into the Room, which is already full of Air, and in a perfect State of Rest, because there is no Passage for it to go out at; the Register having closed up the Funnel, and the Doors and Windows of the Room being shut.
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.
_Sixthly_, IT will be obvious to every Person, who examines the Construction of this Machine, that the Chimney will not require sweeping in less than two or three Years; and that it is morally impossible the Chimney can ever take Fire.
_Seventhly_, IT has been already observed, that no part of the current of Air, that passes continually through the Fire, is supplied from the Doors, Windows, or Crevices of the Room: For the same Reason, the Candles, in all sorts of Weather, will burn clear; the Light will be pleasant, equal, and steady; and there will be a considerable Saving in that Article.
_Eighthly_, WHEN the Room is thoroughly warmed in the Day-time, it will cool but a few Degrees during the Night; and by shutting up the Fire-Place over Night, and excluding the external Air, the Fire will be found in the Morning without any sensible Diminution, ready to blaze out, by the Addition of a Stick of Wood, or a few Coals; which every body knows is an Advantage, that never could be obtained in common Chimnies, with a Coal Fire, without a great Expence, and much Danger.
THESE, and many other Advantages, that would be tedious to enumerate at present, will be found to result from this useful Invention. Several of the Stove-Grates are already set up; and Orders given for the erecting others in many Houses in _London_ and the Country.
SOME are of Cast Iron, in its plain, natural Colour; and others have a Case, richly ornamented, that is put on, and taken off, at Pleasure. The Inventor hopes he shall be permitted to publish the Names and Places of Abode, of those Noblemen and Gentlemen, who have encouraged this undertaking.
BY this Method it will be in the Power of those who incline to become Purchasers, to inform themselves of the Truth of every Particular, by Persons of undoubted Credit and Veracity; and to know, with Certainty, what they are to expect, without laying out their Money, upon what they might suppose, an unexperimented Project; the Success whereof might otherwise be uncertain.
THERE are Three Sizes of these Stove-Grates, adapted to the Dimensions of the Rooms where they are set up. They are all made of Cast Iron, which will endure longer, and come much cheaper, than if they were made of wrought Iron.
_Ft._ _In._ _Pts._ The smallest { High 2 3 0 } Size, Price { Broad in Front 1 5 0 } over all 7_l._ 7_s._ set up { Depth from Front to 1 0 0 } Back The Space that contains the Fire within this Stove, Broad in Front 1 3 0 Depth of the Bars 0 5 6 From Front to Back 0 5 6 Middle Size, { High 2 4 6 } Pr. 10_l._ 10_l._ { Broad in Front 1 9 0 } over all set up { Depth from Front to 1 0 0 } Back The Space that contains the Fire within this Stove, Broad in Front 1 7 6 Depth of the Bars 0 8 0 From Front to Back 0 8 0 Largest Size, { High 2 10 0 } Pr. 13_l._ 13_l._ { Broad in Front 0 2 4 } over all set up { Depth from Front to 1 4 6 } Back The Space that contains the Fire within this Stove, Broad in Front 2 3 0 Depth of the Bars 0 10 6 From Front to Back 1 0 0
I FIND, by my own Experience, that the smallest Size of these Stoves, will warm a Room of Twelve or Fourteen Foot Square, or the largest Dressing Closet. The Middle-sized Grate will warm a Room of 20 Feet + 26, and 12 or 14 Feet high. The largest Size will warm a Room of 50 Feet by 25, and about 20 or 22 Feet high.
AS I have not advanced any thing, but what I have proved from my own Experience, I shall omit what might be said from the Testimony of others, to Time, and the real Merit of the Machine; which, in all Respects, will answer for itself. For the Beginning of this Attempt was founded upon Theory and Mechanick Principles, supported by Observation and Experience of what had happened before.
BUT had not the same Observation and Experience, likewise confirmed the Use of this, and all the Advantages mentioned, I should not have offered it to the Publick.
_Jermyn-Street, March 22, 1753._
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_ADVERTISEMENT._
The Inventor of this Stove-Grate has contrived a Stove for a Laundry, which answers all the Ends desirable, without any other Fire, and at one Third part of the usual Expence that keeps a Fire in the common Way. It is moveable to any part of the Room; and stands on a boarded Floor with the greatest Safety. It likewise may be placed in a Room where there is no Chimney, and will serve for Airing large Rooms, far preferable to the common Braziers; it warms a Room sooner, with greater Safety, and much less Expence: For Half a Bushel of Coals will go farther than a Bushel of Charcoal in the common Way.
_FINIS._
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Transcriber’s Notes:
Punctuation has been made consistent.
Variations in spelling and hyphenation were retained as they appear in the original publication, except that obvious typographical errors have been corrected.