Page:Encyclopædia Britannica, first edition - Volume I, A-B.pdf/80

 54 AGRICULTURE. moft numerous, will, be fufficient. But, if the fprings fig. i. b, and thus fixed to the head A B. It is not be irregularly difperfed through the whole marilh, as is perpendicular to the head, but placed obliquely, fo as frequently the cafe, fide-drains parallel to the principal to make the angle formed by the lines A B and E B one will be nece/Tary to intercept the water that comes about 60 degrees. The {heath is about 13 inches long, from the higher grounds and fepplies the fprings. Crofs befides what is driven into the mortoife b; about three drains, communicating with the parallel and principal inches broad, and one inch thick. drains, are likewife neceffary; and fhould all be kept o- The {heath is fixed to the mold-board, as in fig. 11. E, pen till the foil hath fully fubfided, and become firm; in the fame manner as the wred is fixed to the head in then the fide-drains and crofs-drains may be convert- fig- 7ed into hollow-drains, in the manner above defcribed. The Mold-board is defigned to turn over the earth But the principal drain, efpecially if the marifii be ex- of the furrow made by the plough ; and it is obvious, tenfive, ftiould always remain open. that, according to the pofition of the {heath, the moldboard will turn over the earth of the furrow more or left fuddefily. Befides, when it forms a left angle with the S e c t. V. Of Tillage. head than 60 degrees, the plough is in great danger of being choked, as the farmers term it. Tillage is the operation of breaking the foil into The Larger Handle, fig. 3. F A, is fixed to the head, fmall particles, by (Hrrihg and turning it over, laying it by driving it into the mortoile a, fig. 1. It is placed in tip in ridges, lire. In this part of agriculture, it is ne- the fame plane with the head; and its length from A F cefiary to be acquainted with the different foils proper is about five feet four inches, and its diameter at the for nourifhing plants; the indruments beft adapted for place where it is fixed to the beam is about two inches ftirring and turning them over; and the conftruftion and and a half, and tapers a little to the top F. About ten manner of ufing thefe inflruments. inches from A, there is a curve in the handle, which, Soils, with refped; to tillage, may be divided into when F is raifed to its proper height, makes the lower ftiff and light, wet and dry, deep and {hallow. This part of it nearly parallel to the {heath E B. This curve divifion is the more proper on this account, that the me- is defigned to ftrengthen the handle. The proper pofithod of performing the operation of tillage has always tion of the handle is, when the top F is about three feet a reference to one or more of thefe qualities of foil, and two inches higher than the bottom of the head A B. to no other. The longer the handles, the plough is the more eafily The indruments employed in tillage are various ; as managed, becaufe the levers are more diftant from the the plough, the harrow, the roller, ire. which are a- centre of motion. The higher the top of the handles, gain greatly diverfified by differences arifing from their the plough is more eafily raifed out of the ground, procondruftion and particular ufes. vided they be no higher than the lower part of a man’s breaft. The Beam, fig. 4. is fixed to the largerv handle and i. Of the Scots Plough. the {heath, all of which are placed in the fame plane In Scotland, this plough is dill the mod common with the head. The length of it, from H to I, is aand the mod generally underdood. If properly made, bout fix feet; its diameter is about four inches. When it is the bed plough for anfwering all purpofes, when the plough is in the ground, the beam ftiould be juft high only one is ufed; though others are, perhaps, more pro- enough not to be incommoded by any thing on the furper for fome particular purpofes. face. The parts of which this plough is .compofed are, the The pofition of the beam depends on the number of head, the beam, the fheath, the wred, the mold-board, the cattle in the plough. When two horfes are yoked, the two handles, the two rungs, the fock, and the coulter; beam ftiould be placed in fuch. a manner as to make the the two lad are made of iron, and all the red of wood. perpendicular diftance betwixt the bolt-hole of the beam The Head, Plate VIII. fig. i. is defigned for open- and the plane of the head about 21 inches; when four ing the ground below. The length of the head from horfes are yoked, two a-breaft, this diftance ftiould only A to B is about twenty inches, and the breadth from be about 18 inches. A to D about five inches; C is the point upon which the The Sock, fig. 5. B P, is fixed to the end of the head, fock is driven,' and the length from B to C is about fix and is about two feet long. In fitting the fock to the inches ; a is the mortoife into which the larger handle is head, the point ought to be turned a little to the land fixed; and b is the mortoife into which the {heath is fixed. or left fide ; becaufe otherwife> it is apt to come out of The head is that part of the plough which goes in the land altogether. When turned to the left, it likethe ground; therefore the fhorter and narrower it is, the wife takes off more land; when turned upwards, the friffion will be the left, and the plough more eafily plough goes {hallow; and when downwards, it goes drawn; but the longer the head is, the plough goes deeper. more deadily, and is not fo eafily put out of its direc- The Coulter, fig. 6. is fixed to the beam, and is -tion by any obftnndions that occur. - Twenty inches is about two feet ten inches long, two inches and a half confidered as a mean length; and five inches as the mod broad, (harp at the point and before, and thick on the convenient breadth. back, like a knife. It is fixed and diredted by wedges, The Skeath, fig. 2. E, is driven into the mortoife, fo as to make the point of it equal to, or rather abefore little