rate of 10 acres per day, with one man, a boy, and two horses, especially in the busy time of harvest, when it would be impossible to spare so many men and horses as are required to break up the land effectually with the common ploughs.
The price of Mr. Cooke's Improved Drill-plough, together with Horse-hoe, &c. was in the year 1790, twelve guineas.
Excellent, however, as Mr. Cooke's machine unquestionably is, it must be acknowledged, that in some parts it is too complicated. This circumstance has induced Dr. Darwin to apply his versatile talents to the purpose of devising improvements in the construction of this grand national plough, which will transmit his name to posterity, as an enlightened agriculturist, no less than a medical philosopher who has deeply searched into the recesses of Nature.—Of these essential improvements we are (by the liberality of Mr. Johnson, the publisher of Dr. Darwin's classical work, entitled "Phytologia, or the Philosophy of Agriculture,") enabled to communicate accurate engravings, together with an analysis of the subject, contained in the appendix to that useful book.
Description of the Plates representing Dr. Darwin's improvement of the Drill-plough.
Plate I. Fig. 1, a, a, are the shafts for the horse, fixed to the centre of the axle-tree, by a simple universal joint at z, from which, if the horse move in an oblique course, either spontaneously, or designedly, to avoid trampling the rows of corn, in hoeing, the person guiding the plough behind, may keep the coulters in any direction at pleasure:—b, b, are shafts or handles behind, for the man who attends the drill coulters or hoes: these handles are applied to the axle-tree before, and have a transverse piece about 6 inches from the latter at g, g, in order to support the seed-box (Fig. 2.)—At the distance of about one foot behind this, there is another cross piece at c, c, called the coulter-beam, which is about 4 feet 2 inches long, 6 inches wide, and 2 inches thick: it is perforated with 2 sets of square holes, each set consisting of six, to receive the coulters in drill ploughing and the hoes in horse hoeing.
The light square holes are 9 inches distant, and are designed to receive the coulters, or hoes in the cultivation of wheat, the rows of which are to be 9 inches apart: the six dark square holes are 7 inches from each other, for the reception of the coulters or hoes in the cultivation of barley, the rows of which are to be at the distance of only 7 inches. This coulter-beam has likewise 6 circular holes at one end, and 6 round iron staples fixed into the edge of the other part of it: into these are inserted the ends of the tin flues, which intersect each other, and convey the seed from the bottom of the box into the drills or furrows, when the coulters are properly arranged in the square holes. The person guiding the machine can raise these coulters, or hoes, out of the ground, when passing to or from the field, or in turning at the end of the land; and may thus suspend them on the iron springs d, d, which at the same time fix the shafts to the axle-tree, so that the wheels will follow in a similar direction with the horse.—e, e, are wheels, four feet
