Harrow, an implement of agriculture, -commonly used, for the purpose of covering seed with earth. There is, however, another object of equal importance, to which it may beapplied, namely, to pulverize the soil previously to its receiving the seed.
Common harrows are of different forms. The first we shall notice, has two bulls, four feet in length, and eighteen inches apart, each of which is furnished with four wooden teeth. The second has three bulls, provided with twelve similar teeth: a third has four bulls, and twenty teeth, composed generally of iron, which are ten, eleven, or twelve inches apart. The last mentioned implement is preferable to either of the former ; as, on account of its iron teeth, it is better calculated for covering the seed ; but it is still very imperfect, and the use of it attended with many inconveniencies. Hence different harrows have been invented at various periods, the principal of which we shall describe in the order of time.
The earliest that merits notice is the Harrow-plough, invent' d in. the year 1/03, by a Mr. Wood, of Chelmsford, Essex : a full account of which appears in the 2d vol. of the Museum Rusticum et Commerciale. It consists of a common harrow-frame, 7 feet in length, and 4 in breadth, to which are fitted 14 iron shares, of the form of a heart, with a rounded point, being hollowed underneath, and convex on theup-per surface: the edges of the rounded point, and two sides of these shares, are sharpened in the same manner as a common hoe ; and the shares are disposed in the following order ; the letter A representing the front, and B the back of the frame.
The design of this implement is to clear turnips from weeds, etc. Each share is about 14 inches distant, and, when the harrow-plough moves forward, the shares marked 1, 4, 7, are the first, each of which cuts the plants or weeds in its way. These are succeeded by others marked 2, 3, 5, and (5, which together form seven shares. The seven remaining behind are intended to complete the work commenced by the first row. Thus each share clears about 8 inches of land in width, and leaves the space of 6 inches untouched. This method of eeding turnips has been found much cheaper and more effectual than the common practice : for the shares cut deeper, and move the ground better than labourers will stir it with their hand-hoes. Besides, the harrow-plough, it is affirmed, will also bring land to an excellent state of improvement, after it has been three or four times ploughed.
In the year 1795, a harrow upon a new construction was invented by Mr. Edward Knight, of Great Bardficld, Essex, for which the Society for the Encouragement of Arts, etc. in 1796, conferred on him a premium of 15 guineas. The purpose of his contrivance is to obviate the irregular motions, sudden and incessant checks, and various other in-conveniencies attending the use of the common harrows. Hence Mr. Knight has contrived two joints, A, A, in the axle-tree, one of which in the subjoined cut is covered, in the same manner as when the harrows are at work: the other is uncovered, to show the construction of the joint. There are also two joints, a, a, in the front of the bar, by means of which, from the pliability, both of the tree and of the bar, the course of the wheels is facilitated ; they are thus kept in their proper direction in the furrow ; and as they occupy a very small space of ground, the implement is more easily and conveniently turned.
As the breadth of the furrows frequently varies, Mr. Knight has, for contracting the harrow, so constructed his implement, that part of the bar B, which is fastened by two pins, b b, can be taken off, as often as may be found necessary. Part of the axle-tree, and of the hind bar C, both of which are secured by the iron bolt D, may also be removed; the exterior parts, that still remain, may be joined and fastened by one of the two pins in thebar, and by a shorter bolt d, intended for the axle-tree and hind-
If farmers work the harrow with two horses of unequal height, the horizontal direction or evenness of the joints is apt to be considerably changed. To remedy this inequality in the size of cattle, the inventor has added a whipple-tree E, that may be raised or lowered at pleasure, by means of notches, c, to which it is connected by a ring.
In light, barley lands, when the harrow is adapted to the draught of one horse, by contracting it in the manner already directed, there are two strings conveyed by an equal number of rings from the axle-tree, through two loops f, f, beneath the front-bar. The hind-bar is supported by the wheel F, which is delineated both in the first cut, and in the second, on a larger scale : by the aid of this wheel, the implement is conveyed to the field on the axle-tree bar, serving as a substitute for a sledge. There are a'so two wooden pegs g, g, by which the harrows are secured, when turned upon the carriage.
In case it should be objected, that the harrow must be expensive on account of the iron, the inventor states, that an axle-tree and joints maybe readily constru6ted of wood, upon the same principles as exhibited in the last cut, at the letter G; though he prefers iron to any other material : and, if the wheel under the hind-bars should not be adopted.. Mr. Knight has placed a slider, H, that works with a pin, and, when not in use, is fastened under the axle-tree. He observes, that his harrow may be easily raised or lowered, according to the surface of the land, by fixing an iron with notches (similar to those on the fore-bar, which support the whipple-trees), on the hind-bar, instead of the hooks; and by putting the latter on those irons. He computes the price of his harrows, if new iron be employed, at 41. 13s.
In the "Letters and Papers of the Bath and West of England So-ciety," is an account of an implement, invented by the Hon. Mr. R. Sandilands, and denominated by him a Chain and Screw Harrow, of which we have annexed the following representation:
If the ridges be high, and require to be harrowed through their whole length, that object will be effected by Mr. Sandilands' implement : as by lengthening the chain (which is commanded by the screw), the harrow, when drawn along, will form an angle down-wards, and thus pass over every part of the curve of the ridge in proportion to its extent; which, according to his statement, may be nine feet, the distance from A to B; whereas the whole extent from C to D, is said to be only about five feet and a half. When the crowns of the ridges have been sufficiently harrowed lengthways, the chain may be shortened by the screw, which forms an angle upwards : the harrow is then drawn by horses, one on each side of the furrow, which will be completely reduced as well as the sides of the ridges, if 18 feet in breadth.
If the harrow is to be drawn across even ground, or high ridges, in such cases, it may, by the aid of the screw, be made horizontal, so as to work in the manner of a solid harrow without a joint. The teeth of Mr. Sandilands' implement are square, and fixed in the usual way, being nine or ten inches below the wood, ' and of such strength as the land may require. They cut or tear the ground regularly every four inches, without clogging, Unless at the extreme angles, where the teeth are necessarily put somewhat closely together : they may, however, be cleared with the utmost facility, by raising them a little from the ground. The figures 1, 2,3, 4, etc. point out where the twelve teeth on each side of the harrow are placed.
Mr. Sandilands observes, that where a strong brake-harrow is not necessary, by making the teeth shorter or lighter, 48 tines may be obtained, which will tear the ground at every two inches, cover the seed well, and make a fine mould. He farther recommends to construct harrows for every purpose, and of every size, on the principle above stated ; as, in such, case, no tooth can follow the track of another, and all are kept in constant a6tion.
The same gentleman has also invented another implement, called a Wrack-harrow, from the speedy manner in which it collects the wrack, or roots of couch-grass., and other noxious weeds. Of this contrivance the annexed figures represent the plan and profile:
It is composed of a plank of tim. ber, six feet long, nine inches broad, and two inches thick, in which are fixed two rows of teeth, viz. twelve in the front, and thirteen behind : each row is about four inches apart, and the teeth are five inches distant ; so that they operate at the distance of 21/2 inches from each other. They are in length about seven inches below the wood, three-quarters of an inch square, and pointed diamond-wise, so as only to catch whatever may be brought above ground by previous harrowing, without penetrating the soil. To the plank are joined shafts for a horse, and handles for a man to guide it, of such length and strength as may be deemed necessary.
This machine is used in the following manner: When all the weeds are brought to the surface, the wrack-harrow is drawn across the field; the person who holds the handles pressing a little on them, till the plank has passed over the first furrow, on which the harrow is suddenly lifted, without stopping the horse ; thus, all the weeds col-lected by the harrow will fall into the farrow, whence they may be removed or burnt, at the option of the farmer. If, however, the horse be not steady, it will be requisite to employ a boy for the purpose of leading him; in order that the couch-grass, etc. may be properly eradicated.
A patent was granted in the year 1799, to Mr. WILLIAM Lester, of Yardley-Hastings, Northampton, for his invention of a harrow, by which the inconveniencies attending the implements constructed on the common plan may be effectually obviated.
The patentee makes his harrows of various sizes, to be drawn by one, two, four, or six horses, so as to suit every kind of soil. The first size is six feet in width, and of equal length; the teeth are twelve inches distant in every direction, and there is an interval' of one inch and a half between their tracks, in every line of draught.. This size is more pe-, culiarly adapted to harrowing-in every species of grain and seed, especially on lay, flag, or whale-land. The second size is 71/2 feet wide, and 6 feet 9inches in length; the teeth are 14 inches asunder in every direction, and an intermedi-ate space of two inches occurs between their tracks, in each line of draught. This implement is particularly calculated for clearing foul land. The third size is 9 feet in length, by 7 feet 9 inches in breadth; the teeth are 1(5 inches apart in every direction, and a space of 21/2 inches intervenes between the tracks in each line of draught. The last mentioned harrow is, in the opinion of the patentee, eminently adapted to the cultivation of foul land, especially for clearing fen-fallows of couch-grass.
The superiority of Mr. Lester's patent-harrow is stated to consist in the impossibility of its clogging, or driving the soil together in heaps. Being divided into two parts, of equal length (which are drawn by two centers united in a third), it has a steady uniform motion, and is effectually prevented from diverging into any oblique direction. Another excellence in this contrivance is, its couching over both ridges and furrows, and its yielding to all the inequalities of the soil; besides, from the diagonal position of the bulls, and the irregular arrangement of the teeth, each tine is drawn in a different direction, so that no one tooth can follow another in the same track ; whereas, in the common harrows, one half of the teeth run in the same course.
In the .9th volume of the Letters and Papers of the Bath and. West of England Socity, there is a description of a pair of harrows and of a drag, or heavy harrow, invented by Mr. H. Wynne. His implements are constructed in such a manner, that each pin makes a separate track, and that the intervals between those tracks are all equal; so that the entire ground, over which the harrow passes at one time, will be marked with lines three inches apart. The pair of harrows is seven feet six inches broad ; and the inventor asserts, that the same horses will, by means of it, work one fourth more ground, and perform such labour much better, than by any other harrow. Mr. Wynne's implement is stated to possess this farther advantage, that when the pins or teeth sink into the earth, the posts being nearly parallel to the line of draught, admit all roots, stones, and other obstru6tions to pass freely between them, and also beneath the rails by which they are connected. And, as the hinge is within the tine, when the harrow is drawn up and down ridges, it accommodates itself to the shape of the ground ; the joint rising when the harrow is on the top of a ridge, and sinking when it is in the furrow.
The drag, or heavy harrow, likewise invented by Mr. Wynne, is constru6ted without a joint, and will work a piece of land six. feet three inches in breadth, leaving intervals of five inches between the tracks. The principle is simi-lar to that on which the implements just described are formed and which, the inventor says, is applicable to harrows of any size ; as the intervals between the tracks may be varied at pleasure, the regularity being still preserved. - The spikes or teeth here employed are made of square iron, pointed and bent forward diagonally; they are fixed in such a direction, that the line of the track may pass through their angles.
A patent was granted in May of June, 180J, to a Mr. WILDE, for a harrow on a new plan. His invention is intended to obviate the inconveniencies attending the common harrows : from the ingenuity and simplicity of its construction, it appears to merit attention. The set of harrows, when put together for work, consists of four, which are constructed in the usual manner, and with the usual number of tines. These are placed nearly parallel to each other, and are combined by means of three iron links, which are moveable where they are joined to the harrow: the centre link is fitted in an-oblique direction, and is longer than the other two, which are set straight. All the links, however, are placed loosely, in order that the implement, when joined together, may have a little play-room. This ingenious harrow is fastened to the bearing-bar, to which the traces are affixed, by means of an iron pin that is attached to the chain-hook, passing through holes made at different distances in the bar, so as exa6tly to give the requisite direction to the harrow. - Thus, the equal course of the implement is secured; and the work is more uniformly performed, and with a greater degree of regularity.
Mr. WildE makes harrows for five-yard lands, exclusive of the farrows; but they may be adapted to any size required. The horses may likewise be set to draw abreast, or where the soil is very Wat and heavy, to follow each other in the furrow, and thus to prevent the land from poaching. The patentee is of opinion, that a considerable-saving might be made both in seed, and in the labour of horses, three of which are said to be fully sufficient, where other harrows require four. His implement may also be employed as a rake, or for any similar purpose.
From the great importance of harrows in tillage, we have been induced to extend this article to a considerable length. - Although we do not pretend to decide on the relative value and practical utility of the different inventions or improvements before specified, yet we should probably select the implements contrived by Mr. Sandi-lands, without prejudice, however, to the merits of the rest, which are doubtless calculated to be eminently useful in different soils and situations.