The following comes from Part 2, Book III of John Claudius Loudon's Encyclopedia of Gardening (1835 edn)
2098. The usual mechanical agents employed in garden-culture may be classed as follows: —
1. Tools, or simple implements for perforating operations on the soil, and other dead or mineral matters;
2. Instruments for performing operations on plants or on insects and vermin;
3. Utensils for habitations of plants, or the deportation or retention of either dead or living materials;
4. Machines, or compound implements, for any of the above or other purposes; and,
5. Articles adapted, manufactured, or prepared, so as to serve various useful purposes.
The common character of tools is, that they are adapted for labour which requires more force than skill; they are generally large, and require the use of both hands and the muscular action of the whole frame, often aided by its gravity. Tools consist of two parts, the head, blade or acting part; and the handle or lever, by which the power is communicated, and the tool put in action. As almost all tools operate by effecting mechanical separation between the parts of bodies, they generally act on the principle of the wedge and lever, and consequently the wedge-shape ought to enter, more or less into the shape of the head or blade of most of them, and the lever or handle ought to be of some length. Where the handle is intended to be grasped and held firm, its form may be adapted for that end, as in the upper termination of the handle of the shovel or the spade; but where the human hand is to slide along the handle, then it should be perfectly cylindrical, as producing least friction, as in the hoe and the mattock. The materials of which tools are composed are almost exclusively iron and timber; and of the latter the ash is reckoned to combine most strength and toughness, the willow to be lightest, and fir or pine deal the straightest. The best quality of both materials should, if possible, be used, as scrap-iron and cast-steel, and root-cut young ash from rocky steeps. For light tools, such as the hoe and rake, the willow, or pine deal, may be used for the handles, but in scarcely any case can inferior iron or steel be admitted for the blades.
2100. Garden-levers are of two species, the removing and the carrying lever. The removing-lever (fig. 290.) is a straight, and generally cylindrical or polygonal, bar of iron, somewhat tapered and wedge-shaped or flattened in the thick end: it is used for the removal of large stones or other heavy bodies, in which its advantage is as the distance of the power (a), from the fulcrum (b), &c. The carrying-lever, or handspoke, is used in pairs for carrying tubs of plants or other bodies or materials furnished with hooks or bearing staples, under or in which to insert the handspokes. Two of them united to a platform of boards form the common hand-barrow.
2101. The pick (fig. 291.) is a double or compound lever, and consists of the handle (a), which ought to be formed of sound ash timber, and the head (b), which ought to be made of the best iron, and pointed with steel. There are several varieties: the first, the pick with the ends of the head pointed (fig. 291.) is used for loosening hard ground, gravel, etc.; the second, or pickaxe (fig. 292.) with both ends wedge-shaped, positions, and sharp, is used for cutting through the roots in felling timber; the third, or mattock (fig 293), is used chiefly for loosening hard surfaces, and for grubbing up roots of small trees or bushes. It is sometimes called a crow, and also a grubbing-axe, hoe-axe etc.
2. The spade (fig. 294.) consists of two parts; the blade, of plate-iron, and the handle, of tough root-cut ash timber, rather longer than the handle of the pick, but generally about two feet nine inches. The blade consists of two parts; the plate, by which the soil is cut and carried, and the tread, which is a piece of strong iron fixed on the upper edge of the blade, to receive the impulse of the foot of the operator. Spades are manufactured of different sizes, and usually with a flat blade; but perforated blades
(fig. 295) are sometimes prized, as cleaning or freeing themselves better from earth in adhesive soils; and semi-cylindrical blades, or what canal-diggers call grafting-tools, are preferred for the same reason, and also as entering the soil easier, because gradually,
and in effect as if a flat spade with a pointed or shield-like curved edge were used. Spades with curved edges or pointed blades are easiest to thrust into the earth in hard
or stiff soils, and clean themselves better, but they are more apt to leave untouched parts (baulks) in the bottom of the trench than the common square-mouthed spade. They are the best species for new-ground work, but are not well adapted for culture. (See Gardeners Magazine, vol. v. p. 135.)
2103. The sender-foot spade (fig. 307.) should be made very strong, the shaft, or handle, square, with the angles rounded off, and strongly plated over where it is joined to the cross angle at top and to the blade below. The blade is about fourteen inches across and twelve inches deep; quite perpendicular, with sharp cutting edges, and a hilt or piece of iron (a) riveted on for the feet. For the stubbing of hedges, taking the top sods off drains, and various uses where strength is wanted, this spade will be found a most powerful instrument. (Gard. Mag., vol. vii. p. 86.)
2104. The Flemish spade (fig. 308.) has a long handle, in some cases to the extent of six or eight feet, but no tread for the foot of the operator. As the long handle forms a very powerful lever, when the soil is easily penetrated, it may be dug with greater ease by this spade, than with any of the common forms. For the same reason, the labour of filling carts with earth, and that of throwing earth to a distance, is less with the Flemish spade than with any other.