298 General Notices. 



ing ones in the centre of the bar : these holes are one fourth of an inch in 

 diameter. Into the 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 good iron, 

 edged with steel, as far back as the hole where the bolts upon which they 

 turn pass through. They are 3 in. broad where the hole is pierced; and, 

 behind the cutter-bar, as is seen in the plate, they are bent clown about 

 2 in., to allow the rollers and canvass to operate, as shall be afterwards 

 described. After being continued horizontally about 3 in., they are again 

 bent up, and their extremities placed above the movable bar. They are 

 made about 13|in. long from the point to the hole, and about 7|in. from 

 the hole to the extremity backwards. Both upper and under cutters are 

 sharpened on both sides, similarly to a pah- 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 ; which 

 would allow the edges of the cutters to separate, and of course the machine 

 would get deranged, and woidd not operate. The points of the under or 

 fixed cutters are 6 in. separate ; of course the holes in the bar, by which 

 they are fixed, are 6 in. apart. The bolts of the upper or movable cutters 

 are intermediate, that is, 3 in. from the others ; so that the cutter-bar is 

 bored from end to end with holes half an inch in diameter, and 3 in. distant. 

 The small holes, with the pins which prevent the fixed cutters from shifting 

 their places, are each l^in. 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 l^in. 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 brass, to diminish the friction as much as possible ; and, for the 

 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 

 6 in. between the points of the latter ; so that the breadth of the machine is 

 exactly 6 ft : 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 sur- 

 face, one of 6 ft. 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 ll, of 18 teeth each ; these move the horizontal shaft v, and the 

 wheel w, which is fixed to the end of it. The wheel w has 36 teeth ; and the 



Einion x, which it turns, and which is fixed upon the gudgeon of the roller y, 

 as 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 



