4JM SCIENCE OF AGRICULfURE. Part 11. 



inches in diaraetcr. The wheels are {ilaccd as near the front of the frame as possible, the reason for 

 whicli will appear when the general dascription of the machine is given. The wheels bb are connected 

 with the mam axle (n), in such a manner as that they may turn upon it, similarly to a carriage-wheel, 

 without moving the axle with them; or they can be fixed to it at pleasure, so as to turn it round with 

 tiiem as occasion requires. For this purpose, the holes in the naves are circular ; and of course so much 

 of tlie axle as passes through them is round. There are cross flenges, cast upon the nave, which catch 

 hold of the coupling box e when the machinery is to be moved, and are disengaged from it by the handle 

 F, when the machine is going, without moving the machinery. In the engraving, this part of the apparatus 

 is entirely concealed at one of the wheels, except a small portion of the handle at ii. The other coupling 

 box is but faintly represented at e. The handle f has a joint in it, which is fixed to the other half of it, 

 which passes through the frame of the machine, and terminates with the handle h ; so that both coupling 

 boxes can be managed by the driver, standing at n, although they are on opposite sides of the frame. 

 The main axle (o) is 3| feet long between the shoulders, and eight inches from the shoulders to the coupling 

 box : the frame of the machine is four feet broad, by seven feet long. Fixed upon the main axle (d) is the 

 beveled wheel (i) of sixty teeth, part of which is seen in the engraving. This beveled wheel moves two 

 pinions of ten teeth each. These pinions are concealed in the plate by the frame of the machine : one of 

 them turns the crank-rod (k), and the other gives motion to the coupling wheels (l l) upon the top of the 

 frame. The crank-rod (k) being thus put in motion as the machine moves forward, the crank m, which 

 gives motion to the cutters, revolves with a uniform and steady motion, n is a coupling strap of iron, 

 which connects the crank (m) and the movable bar (o o) together, which is kept in its place by means of 

 the sliding hooks (p p) working in the brass sockets (qq) v/hich are screwed upon the strong iron supports 

 (R R.) It is obvious that as the crank (m) revolves, it will, by pulling the connecting rod (n), give a perpetual 

 motion backwards and forwards to the movable bar (o o). In order that there may be as little friction as 

 possible to the movable bar (o o) there are two friction pulleys fixed to the iron supports (r r), upon which 

 the movable bar (o o) rests. These are not seen in the plate, as they are placed immediately below the bar ; 

 but to any person who considers the thing attentively, they must be readily understood. They are of 

 the greatest consequence, as the back parts of the cutters wholly rest upon the movable bar (o o) ; and from 

 tlie spring which each cutter must necessarily have, the pressure upon it is very considerable. With 

 respect to the cutters, it may here be remarked that the greater body of them is made of iron, edged 

 with the best steel, hardened as much as they will bear, without breaking out into chips when the 

 machine is in operation. The cutter-bar (that is, the bar upon which the cutters are screwed) is strongly 

 screwed upon the extremities of the supports (r r), and is six feet long, by three inches broad, and three 

 fourths of an inch thick. The lower or fixed cutters (s s s) are made triangular, of solid iron, edged v, ith 

 steel, as before mentioned : they are fifteen inches long from the point to the extremity, four inches 

 broad at the base, and nearly one fourth of an inch thick : they are steeled only to the front of the bar, 

 thus leaving a steeled edge of about one foot. In the middle of the base of the cutter there is a hole 

 pierced, half an inch in diameter, and a corresponding one in the bar where it is to be placed. The hole 

 in the bar is screwed ; and, in fixing a cutter, a bolt is passed through the hole in the base, and screwed 

 tightly down into the bar. To prevent a cutter from shifting its place, there are other two small holes 

 pierced, one on each side of the half-inch hole in the base, and corresponding ones in the centre of the 

 bar : these holes are one fourth of an inch in diameter. Into he holes in the bar there are two iron 

 pins firmly riveted below, and left one eighth of an inch above the bar, made to fit neatly into the holes 

 in the cutters, although with a sufficiency of looseness to allow the cutter to be taken easily off when the 

 bolt in the middle is screwed out By this means, when the bolt in the middle is screwed down, a firm 

 and unalterable position is insured to the under cutter. The upper cutters (u u,) &c., like the under ones, 

 are made of goo<l iron, edged with steel as far back as the hole where the bolts upon which they turn 

 pass through. They are three inches broad where the hole is pierced ; and, behind the cutter-bar, as is 

 seen in the plate, they are bent down about two inches, to allow the rollers and canvass to operate, as shall 

 be afterwards described. After being continued horizontally about three inches, they are again bent up, 

 and their extremities placed above the movable bar. They are made about 13J inches long from the point 

 to the hole, and about 7| inches from the hole to the extremity backwards. Both upper and under 

 cutters are sharpened on both sides, similarly to a pair of scissors ; the under ones, of course, upon the 

 upper side, and the upper ones upon the lower side ; thus forming, when the cutters are screwed to 

 their places, a perpetual cutter upon that principle. The bolts upon which the upper or movable cutters 

 work are half an inch in diameter, and are screwed to the bar through a hole of corresponding breadth : 

 they are made to go through the bar about half an inch, upon which a nut is screwed, to prevent the bolts 

 from unscrewing, which they would otherwise do, from the moving of the cutters j which would allow the 

 edges of the cutters to separate, and of course the machine would get deranged, and would not operat(\ 

 The points of the under or fixed cutters are six inches separate ; of course the holes in the bar, by whicli 

 they are fixed, are six inches apart. The bolts of the upper or movable cutters are intermediate, that is, 

 three inches from the others ; so that the cutter-bar is bored from end to end with holes half an inch in 

 diameter, and three inches distant. The small holes, with the pins which prevent the fixed cutters from 

 shirting their places, are each 1^ inch from the large holes; so that the bar, before the cutters are 

 screwed upon it, is pierced first with a small hole, then a large one, then two small ones, then a large 

 one, then two small ones, &c., as may be understood from the plate ; each hole 1| inch apart. The 

 back parts of the movable cutters, as was already mentioned, rest upon the movable bar ; and on each 

 side of every cutter there is an iron pin, of one fourth of an inch in diameter, riveted into the movable 

 bar. By means of these pins, it is easily seen, from the consideration of the plate, that, as the 

 movable bar is pushed backwards and forwards by the crank (m) upon the friction pulleys below it, 

 the movable cutters will have a perpetual motion backwards and forwards. Under the heads of the 

 bolts, which fasten the movable cutters, and the cutters themselves, there is placed a washer of 

 bra,s, to diminish the friction as much as possible; and, for tlie admission of oil, there are two 

 small holes pierced in the head of each bolt. There are twelve movable cutters, and thirteen 

 fixed ones, with intervals of six inches between the points of the latter; so that the breadth of 

 the machine is exactly six feet: but this breadth, from the principle of the machine, may be 

 either increased or diminished, according to the nature of the farm upon which the machine is intended 

 to operate. Upon a perfectly level farm the machine might be made broader ; but upon a farm of sloping 

 or uneven surface, one of six feet in breadth will be found to be work enough for two horses. 

 As it was before stated, the beveled wheel (i) gives motion to the coupling wheels (l l) of 18 teeth each ; 

 these move the horizontal shaft v, and the wheel w, which is fixed to the end of it. The whee w has 36 

 teeth ; and pinion x, which it turns, and which is fixed upon the gudgeon of the roller y, has 18 teeth. 

 This part, however, is misrepresented in the drawing, which was taken from a model which had the 

 rollers turned by coupling wheels, as shown in the plate. The one roller (\') turns the othei (,z),by the 

 pitch-chains {a a), the chief use of which is to keep the sheet of canvass from changing its place by the revolu- 

 tion of the rollers. The canvass, from its gravity, would slip down upon the rollers as the machine moved 

 forward ; and it would twist upon them, by the unequal pressure to which it is exposed by the cut corn 

 pressing unequally upon it : to prevent these derangements, there are loops fixed to the canvass, which 

 are made fast to the links of the chain, about six inches apart ; and there being an equal number of links 

 in both the upper and lower chains, and an equal number of teeth in the four pulleys upon which they 

 Avork, the canvass revolves uniformly, without being in the least deranged by the many casualties to 

 which it is exposed, b is the pole to which the horses are yoked: it is made of wood, and is firmly fixed 

 to the cross rails upon the top of the frame : its length is ten feet from its extremity to the frame of the 

 machine, cc are the swingletrees by which the horses are yoked : they are yoked similarly to horses in a 

 carriage, so as both to draw forward, or push backward, at pleasure. Their heads, of course, are towards 



