364 



SCIENCE OF GARDENING. Pari II. 



the hand is now raised a certain height, never exceeding half that of the man ; if to be 

 raised higher, recourse is had to muscular strength, or the power of the arms to act as 

 levers. 



1858. Carrying. To carry a thing is merely to walk with a greater weight than before, 

 and walking is performed by a series of alternate derangements and adjustments of the 

 centre of gravity, slow or rapid, according as the person may walk or run. According 

 to Delolm, the most advantageous weight for a man of common strength to carry hori- 

 zontally is 112lbs. ; or, if he returns unladen, 135lbs. 



1859. Drawing. In this operation, the upper part of the body is thrown forward, so 

 as to act as a power to counterbalance or lift up the body or weight to be moved ; 

 and by joining to this lifting motion the operation of walking, the weight is at once 

 lifted up and drawn along. This compound operation is exemplified in a horse, when 

 straining at a draught in a plough or cart. He first lowers his chest, then raises it, 

 and lastly steps forward. When drawing at ease, the lifting motion is scarcely dis- 

 tinguishable from the progressive one. 



1 860. Pushing or thrusting is performed exactly on the same principles as drawing, 

 and differs from it chiefly in the kind of implement or machine which requires to be 

 employed ; all machines which are to be pushed requiring to be attached to the animal 

 machine by parts acting by their rigidity ; whereas, tliose to be drawn may be attached 

 by parts acting by their tenacity merely. 



1861. All these operations may be va-ried in quantity, either by a variation in the weight 

 or gravity of the man, or moving power ; or by a variation in the time or rapidity of his 

 motions. Thus a heavy man may, in one movement, lift a weight ten times greater 

 than can be done by one of less weight ; but a light man may, by increasing the time of 

 performance, lift the same weight at ten times. A man, who in digging can apply with 

 his feet five cwt. of his weight towards pushing the wedge or blade of the spade into the 

 soil, has an evident advantage over a lighter man who can only apply three cwt. fof that 

 purpose ; but yet the latter may equal the former, by accompanying his power or foot 

 with a proportionate increase of motion. The power in this last case is said to be 

 obtained by the mornetitum, or quantity of matter in a body multiplied by the velocity 

 with which it is moved. Power, therefore, we thus ascertain, is obtained by matter and 

 motion jointly, and what may be deficient in tlie one, may be made up by excess in the 

 other. Thus, a small, light workman may (though with more animal exertion) produce 

 as much work as a larger or heavier man : for if we suppose the quantity of matter 

 in the , large man to be thirty, and his motion at the rate of two, then if the quantity 

 of matter in the small man be twenty, and his motion at the rate of three, he will pro- 

 duce an equal eflfect with the large man. As small human machines, or little men, 

 are generally constructed of firmer materials, or more healthy and animated, than large 

 ones, the small man performs his rapid motions with nearly as great ease to himself 

 as the heavy man moves his ponderous weight ; so that in point of final result they are 

 very nearly on a par. 



Sect. II. Garden-labors on the Soil. 



1862. The simple labors p)eculiar to arts of culture are performed either in the body of 

 the soil, as picking, digging ; on its surface, as hoeing, raking ; or on vegetables, as cut- 

 ting, clipping, &c. 



1863. Picking. The pick, as we have seen [Jig. 77.) is a blunt wedge, with a 

 lever attached to it at right angles, and the operation of picking consists in driving in 

 the wedge perpendicularly, so as to produce fracture, and then causing it to operate ho- 

 rizontally by the lever or handle, so as to effect separation, and thus break up and loosen 

 hard, compact, or stony soils. It is also used to loosen stones or roots ; and the pick- 

 axe is used to cut the latter. For breaking and pulverising the soil, the most favorable 

 conditions are, that the earth should be moderately moist, to facilitate the entrance of 

 the pick, but in tenacious soils not so much so as to impede fracture and separation. 



1864. Digging. The spade is a thin wedge, with a lever attached in the same plane, 

 and the operation of digging consists in thrusting in the wedge by the momentum 

 (or weight and motion) of the operator, which effects fracture ; a movement of tha lever 

 next effects separation, whilst the operator, by stooping and rising again, lifts up the 

 spitful or section of earth on the blade or wedge of the spade, which, when so raised, 

 is dropt in a reversed position, and at a short distance from the unbroken ground. The 

 separation between the dug and undug ground is called the trench or furrow ; and 

 when a piece of ground is to be dug, a furrow is first opened at that end of it where the 

 work is to commence, and the earth carried to one end where it is to terminate, where 

 it serves to close the furrow. In digging, regard must be had to maintain a uniform 

 depth throughout ; to reverse the position of each spitful, so as what was before surface 

 may now be buried; to break and comminute every part where pulverisation is the 

 leading object ; to preserve each spitful as entire, and place it separate, or isolated as 



