« AnteriorContinuar »
that means or reason be better than his, who main-1 and EF G and HG F the angles made by the tains, that it is advantageous to the growth of corn covings and the back to break its roots, to deprive it of food-to make! In constructing this fire-place, the angles EFG it sick-to close its mouths—to starve it?
and HGF made by the covings and back, should I give you these views in conformity with the be 130°, the fire-place six inches deep from front promise I made you, and regret that I have not to back, in small rooms; and from eight to twelve time to give them with more system, and in better inches in large rooms. It is thought by some, that dress. But such as they are, I am willing for an inch to every foot of the room in breadth is them to undergo the ordeal of rigid scrutiny. If best--thus, if the room be twenty feet square, the they be erroneous, I shall be benefited by the cor-fire-place will be twenty inches deep, measuring rection-if they are true, others will be by their from front to back, along the place where the fire publication.
is made. The vent for the smoke four inches
wide generally; varying, however, with the size JOHN ROBERT WALLACE.
of the opening or mouth of the fire-place. The back should be built erect (and not started in
clining inward as is common) as high as the orON THE CONSTRUCTION OF FIRE PLACES.
dinary height of the wood when the fire-place is To the Editor of the Farmers' Register.
full; ihen projecting inward, and run in that posiThere might be a great saving of fuel among
tion to within four inches of a line drawn perpenus, (for this is a subject that certainly merits at
dicularly from the lower edge of the mantle or tention,) by a proper management of our fire
iron bar to the back, then abruptly sloping back
this is the height of the back, and the point at places, and especially those of our cabins. These are generally so large, burning almost a cart load
which it begins to form the throat, or hollow place of wood at a time, that nearly all the heat escapes
above the vent. When the back begins to slope up the chimney. If they were made smaller, and
inward from the bottom or foundation, it not only on the same principle as those of our dwelling
reflects the heat down against the floor, but it also houses, half the wood would answer the purpose;
obstructs the ascending smoke. and of course, half the labor be diminished in get
A fire-place of the above construction, consists ting it. But even here, although the general form
of the following parts, (which we shall here enuand principle (which appears to be all that is
merate, in order that the following remarks on the aimed at) is obtained, yet even these are not con
nature of the alteration and improvement of the structed according to the just proportions and di- |
old fire-place, may be more clearly understood)mensions of the improved fire-places of Count
the hearth, the opening in front or mouth, the Rumford and Dr. Franklin; as it will appear from
jambs or covings, the back, the mantle supported
by the iron bar, the vent (sometimes confounded the following figures, which illustrate the differ
with the throat) through which the smoke enters ence between the old and the improved fire-places.
the throat, the throat itself above the vent, the
fiue or funnel, through which the smoke ascends Fig. 1.
into the air, and finally the shaft, or what is commonly called the chimney itself. The principal improvement made on the fire-place, was an alteration in the covings; first, in regard to their depth; and secondly, the direction in which they were run-by running them shallower the back of course was brought forward, and consequently, the burning fuel was brought more into the room, and thus the benefit of the heat obtained. And by running them at an oblique angle with the back of 130°, instead of 90° a right angle, the covings were converted into a reflecting surface, by which the heat which lodged in the corners of the old fire-places, and thence escaped up the
chimney, was reflected into the room. The vent Fig. 2.
next was diminished, by which more heat was retained in the fire-place, and the draught strengthened, (or the chimney made to draw better as it is commonly said) and consequently less liable to smoke.
All these different parts of a fire-place and chimney should be well constructed, and in due proportion; for the heat and smoke is affected by all of them. Thus if the mouth is too large, too
much air is admitted for the fire, which has the H same effect in putting it out or cooling it as too
little; and by cooling the fire, of course weakens A B (fig. 1) is the opening in front, BC the the draught, and causes the chimney to smoke. back of the old fire-place, AB and C D the cov- If the covings are perpendicular to the back, ings, and A B C and D C B the angles made by the heat, instead of being reflected in the room, the covings and the back.
will be reflected from one coving against the other. When altered, E H (fig. 2) the opening in Thus if a ray of heat thrown from the centre of front, F G the back, E F and G the covings, the back of the old fire-place at i, impinges on the
coving A B at k, it will be reflected against the ed, accompanied with a great roaring, and the opposite coving C D at n; and of course a person combustion goes on rapidly. sitting in front of the fire, loses the benefit of it, ! Again, if the flue is too large, the draught is unless he be sitting in the corner somewhat facing weakened, and a quantity of soot is formed; for the coving. But if a ray of heat thrown from a in this case the flue contains so much cold air, it point in the centre of the back of the new fire- weakens the draught, and hence not being suffiplace F G at s, in the same direction as in the cient to drive out the soot, it lets it fall on the sides former case, and falls upon the coving G H at o, ) of the flue. The same takes place in the chanit will rebound in the direction towards x, in front nel of a stream, (which has been made use of to -for the angle of reflection is always equal to the illustrate the draught in a chimney.) The stream angle of incidence. A person sitting, therefore, is always swiftest where the channel is narrowest, before the fire, will enjoy the benefit of a ray sol (the volume of water being the same,) hence it is reflected. If the covings be made of a substance able to carry the sand along: but if it suddenly that absorbs more than it reflects, a great deal of sprcads into a large channel by which the stream the heat is lost. They should be made of a ma- is weakened, it drops the sand on the sides of the terial that reflects more than it absorbs, and if channel, or in the deep holes. The stream is alpossible, of one which does not absorb at all. ways swiftest in the middle, and fiequently runs Dutch tiles, fire-stone, marble, and porcelain are backwards at the sides, and hence the sand is left used—common brick and mortar, if it was suffi- there, where the current is weakest. It is on this ciently durable, is the best material; which should principle that soot is formed in a flue, of any conbe smoothly plastered, and kept white-washed, struction. The draught or current of air and smoke for black absorbs too much heat. The best cov-being stronger in the middle of the flue, it drops ing for a fire-place, is that material which is most the soot on the sides where it is weakest. On the durable, least liable to crumble, the least absorber, other hand, when the flue is small, it is heated all and the greatest reflector, and that which is sus- the way up, and the air in it; and thus the draught ceptible of the highest polishi, for the more it is is made to ascend, by the heat rarifying and raispolished the more heat it reflects. Any one may ing the air. be convinced of this, if they will place the bottom If the throat is too large the soot collects in it, of a polished plate of tin (or the bottom of a cof-for the same reason mentioned above. This, howtee-pot) by the side of the face, while standing ever, is an advantage; for if a deep recess be before the fire, so that the ray of reflection may made above the vent, (or a deep throat) nearly strike the face after it is reflected from the tin: а all the soot formed may be collected, when it may higher degree of heat will be sensibly felt. When be swept out. Upon this principle furnaces have the image of the fire is seen on the tin, then the been constructed so ingeniously as to clear the ray strikes the face. A tin plate would be a good fue of soot almost entirely. Any one may notice thing to regulate the position of the covings. The how soot is collected in holes in the back of a fire mantle also affects the heat and smoke. If this place, above the fire, where a brick happens to be too high, the draught is weakened, and the tumble out: for this reason, the throat, vent, flue, smoke puffs out into the room before it reaches the and rough places in the back, should be made vent: if too rugged in the inner-side, it obstructs the smooth. Finally, if the shaft is too long or high, smoke: it should be smoothly and soundly plaster- the chimney is apt to smoke, for then the flue beed, that the smoke may curl around it on the ing too long to be heated all the way, the cold air inner-side.
in it will cool and weaken the draught, and being If the vent is too large, too much heat escapes, heavier too, will press the ascending smoke down and the draught is also weakened-if too small, the chimney in the room: if too short the wind is the smoke is obstructed: if the fire-place is too apt to blow down it. The size of the shaft should large for the vent, it takes in more air than can be generally to that of the flue as 4 to 1. pass up the chimney; as an animal can take in These remarks may serve to show, how the its mouth more than it can swallow: the mouth heat and smoke of a fire-place and chimney, are should ever be in proportion to the vent. It is an affected by the construction of their component established rule in the construction of stoves, and parts. furnaces with grates, that the area of the vent | But the great secret in managing a fire-place, should be equal to the sums of the area of the so as to obtain the greatest degree of heat from open spaces between the bars of the grate through the smallest quantity of fuel, and to prevent smowhich the air is admitted to the fire: but the ob- king, is the management of the draught. This is ject here is more to increase the heat within the easily affected by every part of the fire-place, as furnace by a rapid combustion, which is always in well as by other external causes, as the air, winds, proportion to the strength of the draft, which is at groves of trees, buildings, &c. its smallness and swiftness, (hence the powerful To understand the nature of thc draught-it is heat produced by the mouth of the bellows,) and a current of heated air, produced in the fire-place, therefore cannot strictly apply to an open fire place, as soon as a shovel of coals or a chunk of fire is where the object is not confined heat, but reflect- introduced: which ascends the flue of the chimney, ed. If the mouth was made as small as the vent, carrying along with it the smoke, soot, and other very little heat would be reflected in the room, matter of the Tuel: and is formed on the principle of though the combustion would be more rapid. the expansion and rarification of that element This is well known to those who have been in the The heat of coals rarifying the air just around habit of kindling a fire made of coal, by placing them, divides it in into minuter particles, and conthe kindler before the mouth, so that a small space sequently becoming lighter, they ascend through is left for the admittance of the air, or oxygen. the denser air up the chimney: this produces a The same may be seen by placing a blanket be- partial vacuum (for there is no real vacuum in fore the fire, when the draught is suddenly increas- i nature, though one can be made by art,) around the fuel, into which, the fresh air rushes out of the Although air is so necessary to the fire, too room: this being again rarified as the former por much air, like water, weakens combustion, and contion, ascends and thus a constant current is kept sequently the draught, and renders the chimney up as long as the combustion goes on. As soon as liable to smoke. latent heat becomes sensible, by the collision of These facts suggest some means for the curing fint and steel, and the compression of the air be- of smoky chimneys. Thus, when all the apertween them, or in other words, as soon as a spark tures of a room are closed, too little air is admitted of fire is born into the world, and kept alive by -this weakening the combustion, and that the combustible matter, this current is formed around draught, the latter is not sufficient to drive the it, by rarifying the air. On the same principle the smoke up the flue; the consequence of this is, the heat of the sun produces the winds, (according to weight of the external atmosphere presses the the theory of Dr. Halley, now generally received.) smoke down the chimney into the room, especially This is the case with the great east wind which if the wind blows, in which case the current of blows continually from east to west, in the direc-wind being stronger than the draught, it puffs the tion of the apparent diurnal motion of the sun, smoke into the room. The remedy is to open the and prevails in all the extensive oceans. The heat doors, &c., and admit the air: the same happens of this luminary, warming the air under it, (or when too much air is admitted, which cools, and rather it should be said, warming the earth, and of course weakens the draught, and not being sufthat warms the air by reflected heat-for the ficient to propel the smoke, it is pressed back by rays of the sun have no effect on that medium the external air in the apartment: in this case through which they pass,) rarifies it, and a fresh the doors must be shut. The weakness of the portion rushes in the partial vacuum, in the direc- draught is the most frequent cause of smoky chimtion of the motion of the sun, and thus the cur- neys. This is produced in a variety of ways. rent is kept up. This is also the cause of the Very often a weak fire causes the chimney to north and south winds which blow towards the smoke; för, as the heat and combustion depend on equator: the heat of the sun being hottest there, the draught, so the latter depends upon the forthe air rushes in from those points to supply the mer: so that when the fire is low, the smoke curls consequent vacuum. But to return, the current weakly up the chimney. The remedy suggests or draught thus produced by the heat of the fire- itself-kindle up a brisk fire. place, is supplied by fresh air from out of the There is another way in which the draught is room, which if it were made air-tight, would soon weakened, or rather overcome: for the want of produce a vacuum, in which no animal could long ventilation in the upper part of the room. There exist. But when the air of the room is exhausted, are always two sorts of air in a room where fire is fresh portions are adınitted through the doors, kept-a light and heavy. The former occupies the windows, and crevices of the room: if all these upper part of the room, where, if it has no vent, apertures are closed, the combustion ceases, and it rushes down the wall to the mouth of the firethe fire goes out. Air is no less important to keep place, and curling round the inner side of the manup a flame, than it is to support animal life. The ile, forces its way up, and by its superior strength principle of the air or atmosphere which feeds the drives back the smoke, especially if the draught fire or supports combustion, is oxygen, one of the happens to be weak. There are always two curtwo gases of which the atmosphere is composed: rents passing through the mouth of the fire-place the other is azote. If the air is deprived of oxy- if the room is not ventilated above, as well as gen, it will no longer support combustion for if a through the door; this may be seen, by holding lighted taper be put into a vial of such air, it will two teathers—one at the top, and the other at be extinguished; but if a bit of wire be dipped in the bottom of the mouth of the fire-place-they sulphur and lighted, and then put into a vial of vill be drawn inward: but in the case of the door, pure oxygen gas, it will be rapidly and brilliantly one of the currents is going out at the top, (the consumed, and the melted iron will sink through lighter) while the other (the heavier) is coming the bottom of the vial. The absolute necessity in at the bottom, which may be seen by holding of oxygen or the atmosphere to promote combus- two candles, one in the lower and the other in tion is forcibly presented: if a pipe be admitted the upper part of the door. The upper one will to the fire along the floor, having a communica- be blown outward, while the under one will be tion with the external atmosphere, a current is blown inward. The draught is affected, when suddenly formed, which rushes violently with a several vents open into the same funnel; for the noise from the mouth of the pipe through the fire fresh air rushing in through these-vents out of adup the chimney. This shows what a powerfulde- jacent rooms, puff out the smoke: this ceases, when mand the fire has for air, which increases the heat a draught is formed in every vent by kindling fire and combustion in proportion to the rapidity of a in the different rooms at once. Straight funnels succession of particles of air introduced to fire; affect the draught, because the wind is more easihence, the powerful intensity of heat produced by ly admitted down the chimney to the fire. Large a blow-pipe or bellows. The combustion, and fire-places with small vents affect the draught, and consequent heat, seems to be also in proportion to likewise the contrary. The want of ventilation the smallness of the aperture through which the affects the draught, and of course, the smoke. air is admitted; but this may be still owing to the When the draught is weakened in this way, a pipe rapidity of the current, for this depends upon its admitted to the fire, terminating at the hearth or smallness. From this it well appears, how much within the fire-place, having an external commuthe management of the draught depends upon the nication with the air, will prevent smoking. The air; and as the combustion, and consequently the pipe may be either conducted on, or under the heat, depends upon the draught, and also the smoke Hoor. The draught is sometimes affected by haywhich is driven by the draught, the great picety ing the ventilators for letting out the foul air of a in managing the draught will likewise appear. room, too low down above the fire place, (which
by the by is a very good contrivance for getting second number of the Tennessee Farmer, just received. rid of foul air,)-the light air just spoken of, rush- The first is introductory to the insertion of an article ing through the ventilator, is apt to push out the which formerly appeared in our work, (“Another way smoke into the room, overcoming the draught. Be- of fattening hogs.") From these remarks it may be sides, fresh air too, often rushes in there, (it being inferred, that the economy of our customary way of so low down,) and obstructs the smoke. These raising and keeping hogs, is at least doubtful in a new ventilators would answer remarkably well at the country like Tennessee, where the disadvantage of the top of the wall, where the light foul air is always
plan must be much less than in Eastern Virginia. lodged. (I think it a question however, whether a ventilator for foul air, should be connected with
From the Tennessee Farmer. the chimney, on account of its affecting the draught.) A fire-place often smokes at the kind
ON HOGS RANGING AT LARGE. ling--this is because the draught is not formed,
We invite the attention of our readers, to the which carries up the smoke: this is prevented
article in this number, from that valuable work by using very combustible matterin kindling-such
the Farmers' Register, on the raising and fattenas light-wood, very dry wood, &c. In cabin chim
ing of hogs. It will be found to contain some huneys the shortness and largeness of the funnel
morous sarcasms, on the absurd mode adopted in when the vent is too large (equal in fact to the
Virginia, and with little alteration, too generally chimney itsell,) affects the draught, and smoke
practiced in this country, of rearing this valuable make the vent smaller: this will prevent the wind
animal-a mode which though adopted for its supalso from having too powerful effect on the fire.
posed economy, is in truth, perhaps the most Sometimes one flue and room is filled with the
wasteful, the most extravagant, and the most unsmoke of another flue,-closing the communica
| profitable ever yet devised. The actual loss antion between the two will prevent the evil.
nually sustained in Tennessee, from the manner The draught is not only affected by the construc
in which hogs are generally reared and fattened is tion of the chimney and fire-place, but by other
immense; and would, could it be ascertained with causes--as the wind, &c. This has called in use
precision, astonish those by whom it is resorted to the construction of arches over the top of the fun
under the erroneous impression, that it is recomnel. When a chimney smokes from the wind u
mended by its economy. We should hazard little blowing down the funnel, where there are two funnels in the same shaft, they must be separated
by asserting, that by a more humane and judicious
mode of rearing hogs, double the quantity of pork at top by arches. When a chimney smokes from
could be annually raised from the food now exa particular direction of the wind-as N. W. for instance and is obstructed by any obstacle on the far superior quality.
pended in raising the half-and that pork too, of
To raise hogs with profit, opposite side of the chimney, as higher buildings,
except in a few situations, possessing peculiar adtrees, &c., a funnel of tin swung over the top of
vantages, situations now rarely to be met with, two the chimney to move with the wind, will prove a,
i rules must be observed. First-to feed the sows remedy—the wind claps one part of the funnel;
in such a manner as to enable them to keep the close to the top of the chimney in that direction in which it blows this prevents it from going down
pigs fat until weaned. Secondly, never to suffer
them to become poor after they are weaned. By the chimney, while it turns the funnel (or cap) uploha
P observing these rules, especially with the aid of in the opposite direction, to open a passage for the smoke. The manner in which groves of trees,
clover, it will be easy to make a hog at from twelve
lover; $, to eighteen months weigh double, if not thrice as
or higher buildings, hills, &c. affect the draught is, I mu by obstructing and reflecting the winds in various
19. much, as many now do at two and three years old, directions,
and with no greater quantity of grain than is
now often expended in rearing and fattening the NICHOLAS E, READ.
latter. The suggestions of the writer of the artiCharlotte County.
cle alluded to, are well worthy the attention of all
who wish to convert their corn into pork with proTHE TENNESSEE FARMER.
fit. The absurd selfish notion, that whatever a
hog picks up in the woods, or in his neighbors The publication of a new agricultural paper has fields, is so much clear gain to his owner, ought lately been commenced in Tennessee, edited by | long since to have been banished, by the notorious Thomas Emmerson, Esq., of Jonesborough. Though fact, that many hogs thus raised, after being fatappearing in size and form somewhat suited to its low ted, will not at a reasonable price, sell for as much price of $1 a year, it exhibits such evidence of edi- as the corn cost,consumed by them. Whereas, one torial ability, as promises a valuable work. There is judiciously raised, will sell for double the price of abundant room for the labors of Mr. Emmerson, and the grain expended in rearing and laiting him. If we heartily wish success to his exertions. We may any one doubts the truth of this assertion we only not be altogether disinterested in this wish-for it ask
| ask him to make the experiment on two litters of would operate directly and greatly for the advantage
U pigs, keeping an accurate account of the food of the Farmers' Register, if our brother editor can
consumed, and of the price of the pork yielded by convince the tillers of new and fertile lands of the
"each, and his doubts will be speedily removed.
To keep stock of any description, in a state of south-west, of their mistake in the opinion so very I almost constant starvation, is cruel and immoral, generally entertained, that they have no need for ag- and it will, on a fair experiment, be found, that in ricultural journals--a fertile soil alone being deemed this instance, as well as in every other, Providence sufficient to supply every defect of economical man- has so connected the duty and interest of man, agement, and of agricultural information.
that he cannot violate the former but at the exThe two following editorial articles are from the pense of the latter. Were this great truth wel! understood and well considered, it would produce Force of traction is another expression requiring many valuable improvements in agriculture, it explanation; but here we must enter into miore dewould save the innocent and helpless domestic an- tail, and shall give at once a practical illustration imals from a dreadtul mass of suffering, and it of our meaning. would save the earth, from that empoverishment, A force is most conveniently measured by the by which posterity are subjected to oppressive la- weight which it would be capable of raising; but bors and hardships for its renovation, which an it is not therefore necessarily applied vertically, in enlightened regard to their own true interests, on which direction weight or gravity acts. the part of their ancestors, would have rendered. If a weight of 100 lbs. be suspended to a rope, wholly unnecessary. As the rearing of hogs ought it is clearly exerting upon this rope a force of 100 probably, in the present state of East Tennessee, Ibs.; but if the rope be passed over a pully void of to form a prominent item, of her agricultural pur-triction, and continued horizontally, or in any suits, we propose from time to time, presenting to other direction, and then attached to some fixed our readers the most valuable articles on the sub-point, the weight still acts upon all parts of this ject, which may be within our reach, and we ear- rope, and consequently upon the point to which it nestly request those who may have made any val- is fixed, with a force equal to 100 lbs. and so inuable experiments, to furnish us with a detailed ac-versely, if a horse be pulling at a rope with a count of them, and of their results. Our own ex- force which if the rope were passed over a pully, perience authorises us confidently to assure our would raise 100 lbs., the force of traction of the readers, that regular salting is no less beneficial horse is in this case 100 lbs. Spring steelyards beto hogs than to other stock, and that to spread the ing now commonly in use, we may be permitted salt on ashes in the salt trough, is a mode well cal- to refer to them as affording another clear exemculated to preserve the health of the animals. plification of our meaning. In pulling at a steel
yard of this description, whether the force be ex
erted horizontally or vertically, the index will of From the Tennessee Farmer.
course, show the same amount; and, consequentON BURNING GYPSUM.
Ily, if the strength of the horse be measured by atA subscriber propounds to us the following ques
taching the traces to one of these steelyards, the
number of pounds indicated on the dial will be tions: lst, Will the burning of plaster answer in lieu
the exact measure of the strain the horse exerts,
and the amount of strain is called his 'force of of grinding?
traction.' 2nd. If so, how should the process be conduc
Having fixed as nearly as possible the meaning ted? We should be glad to receive replies to the above
of these terms, which will frequently occur in the inquiries from any of those who have made the
course of our progress, we shall proceed to the
division of the subject. experiment. In the mean time we would advise
It is evident that there are three distinct agents our correspondent to make an experiment on a
and points of consideration in the operation of emall scale. We have heard of burnt plaster being used with advantage near Abingdon, Virgi
| draught, which are quite independent of each nia. We once endeavored to make an experiment
other. They are—first, the moving power and but found it difficult to burn the plaster on a log
the mode of applying it; secondly, the vehicle for heap so as that it would slack. The practice of
conveying the weight to be moved; thirdly, the
canal, road, or railway, or what may be generally burning, nay even of kiln drying to facilitate the la grinding, is condemned by others as very injurious !
termed the channel of conveyance. to the plaster-we should therefore be loth to try it
i All these individually influence the amount of
draught, and require separate consideration; but on a large scale.
the mode of combining these different agents has
also a material effect upon the result: consequently, From the Farmers' Series of the Library of Uscful Knowledge. they must be considered in relation to each other; ON DRAUGHT.
and to obtain the maximum useful effect, with the
greatest economy, in the employment of any It will be necessary first, to explain and define given power, it is evidently necessary that these clearly sume terms which will occur frequently in different agents should not only each be the best the course of this paper, and especially the word adapted to its purpose, and perfect to the greatest draught,' which is the title itself of the treatise. possible degree, but also that they should all be
This word is used in such a very general and combined to the greatest advantage. vague sense, that it would be difficult, if not im- ' We shall proceed at once, then, to examine the possible, to give an explanation which should ap- different agents now employed, the modes of apply equally to all its different meanings.
plying them, and the proportionate effects proIn the expression draught by animal power, it duced. would seem to mean the action itself of drawing, And, first, with regard to the species of moving while, on the other hand, it is frequently used to power;signify the amount of power employed, also the This may be of two kinds, animal and mechandegree of resistance, as when we say the draught ical. of a horse, or the draught of a carriage. Draught By animal power we mean the direct applicapower is also an expression used. We shall, tion of the strength of any animal to dragging or however, in the course of this treatise, confine our pulling, as in the simple case of a horse dragging use of the word to the two meanings-draught, la cart. By mechanical, the application of any the action of dragging-and draught, the resist-power through the intervention of machinery; the ance to the power employed to drag any given source of power in this latter case may, however, tveight.