The Spade.
We will begin our notice of tools by taking that which must have been the first tool invented by man. One of the principal duties assigned to man is the culture of the earth, and this he cannot do without tools, increasing their number and improving their structure in proportion to his own development in agriculture.
Before seed can be sown, it is necessary that the earth should be broken up, and, owing to the structure of the human frame, this task cannot be fulfilled by man without a tool which will enable him to rival many of the lower animals, i.e. make use of those digging appliances which have been furnished by Nature.
It is evident that the first earth-breaking tool must have been a pointed stick, and we find that in Southern Africa, in parts of Asia, and in Australia the Digging-stick is still in use for the purpose of breaking up the ground. The Australians are wonderful adepts in the use of the Digging-stick, which is one of the simplest of instruments, being merely a stick some two feet in length, pointed at one end, and the point hardened in the fire.
The mode of using it is by holding it perpendicularly, pecking it into the ground, and throwing out the loosened soil with the hands. In this way they can excavate with such rapidity, that a strong navvy, armed with the best spade, would not be able to keep pace with a black man armed only with his “katta,” or digging-stick.
In Africa the Digging-stick is used in exactly the same manner, and is generally made more weighty and effective by having a perforated stone fastened on the handle.
Here, again, man has been anticipated by Nature, and the savage of Australia or Africa digs in exactly the same manner as the common Heart-urchin of our shores, sometimes called the Hairy Urchin, in consequence of the number and fineness of the spines, which look just like hairs to the naked eye. The scientific name of this creature is Amphidotus cordatus.
Mr. Gosse, in his “Evenings at the Microscope,” gives so admirable an account of the mode of digging employed by the Hairy Urchin that I cannot do better than employ his own words. After describing the variety of structure of the different spines with which the shell is so thickly set, he proceeds as follows:—
“But what is the need of so much care being bestowed upon the separate motion of these thousands of hair-like spines, that each should have a special structure, with special muscles for its individual movement? The hairs of our head we cannot move individually: why should the Heart-urchin move his?”
“Truly, these hairs are the feet with which he moves. The animal inhabits the sand at the bottom of the sea in our shallow bays, and burrows in it. By going carefully, with the lens at your eye, over the shell, you perceive that the spines, though all formed on a common model, differ considerably in the detail of their form. I have shown you what may be considered the average shape, but in some, especially the finer ones that clothe the sides, the club is slender and pointed; in others, as in those behind the mouth, which are the largest and coarsest of all, the club is dilated into a long, flat spoon; while in the long, much-bowed spines, which densely crowd upon the back, the form is almost uniformly taper throughout, and pointed.”
“The animal sinks into the sand mouth downwards. The hard spoons behind the mouth come first into requisition, scooping away the sand, each acting individually, and throwing it outwards. Observe how beautifully they are arranged for this purpose, diverging from the median line, with the curve backwards and outwards.
“Similar is the arrangement of the slender side spines; their curve is still more backwards, the tips arching uniformly outwards. They take, indeed, exactly the curve which the fore-paws of a mole possess,—only in a retrograde direction, since the Urchin sinks backwards,—which has been shown to be so effective for the excavation of the soil, and the throwing of it outwards.
“Finally, the long spines on the back are suited to reach the sand on each side, when the creature has descended to its depth, and by their motion work it in again, covering and concealing the industrious and effective miner.”
The reader will notice that this mode of digging is exactly like that which is followed by the users of the Digging-stick, the earth being first broken up, and the loosened portions thrown aside. The whole of the description of the spines is exceedingly interesting, but, as it does not bear directly on the present subject, I cannot admit it into these pages.
Now comes another development in digging tools.
We have already seen how effective an instrument a mere piece of stick can be in the hands of a skilful workman, and the manner in which it can tear up a given depth of soil. But, for agricultural purposes, something more is needed, and the ground must not only be broken up, but a certain regularity must be observed, in order to allow space to be accurately measured, and the crop apportioned to the area.
Out of the Digging-stick, then, the Spade was developed, its chief advantage being that it dispensed with the use of the bare hands, and not only tore up the ground, but threw out the loosened soil.
The reader will remember that in the preceding description of the Heart-urchin it was mentioned that many of the spines are shaped at their ends something like spoons, and that their comparatively wide blades are used in scraping the sand and shovelling it aside. In fact, these flattened spines are natural spades, used on the same principle as the modern spade of civilisation.
On the right hand of the illustration are shown two forms of spade, the one being the ordinary garden tool, and the other a rather curious implement which is in great use among the metal mines of Cornwall. The use of the ordinary spade is too familiar to need explanation, and we come to the Miner’s spade. This implement is used rather as a shovel than as a spade, the peculiar bend near the blade preventing the foot from being used as a means of forcing the instrument into the ground. In fact, it is not meant for the same office as that which pertains to the ordinary spade, neither can it be handled in the same way.
In Devonshire there is a kind of spade in general use very much resembling the mining spade, but having a very long handle without any crutch at the end. The natural consequence of this shape is, that the spade cannot be used in the ordinary way, neither can it penetrate the earth to any depth. It can “peel” the ground, so to speak, and can cut away successive layers of soil. But as for digging “two spits deep,” or even one spit, the spade would be absolutely incapable of such a task, no matter how strong might be the hands that wield it. As for the foot, it may be put out of the question.
We will now turn to a few examples of spades in the world of Nature.
The lowest figure represents the fore-paw of the Mole, with its powerful armature of strong and sharp claws, and its broad blade of a palm. The reader will easily see that in this animal the digging powers are wonderfully developed. The peculiar form of the fore-foot closely resembles that of the miner’s spade, while the curvature of the palm serves, almost without exertion, to throw out the earth which has been scooped away by the sharp claws.
To watch a Mole burrow is really a curious sight, the only drawback being that the animal sinks itself so rapidly beneath the earth that a long inspection is impossible. I have kept several moles for the purpose of watching their habits, and have always been interested in their mode of burrowing. I can only define it by using the word “scrabbling.” The animal scurries and hurries about, seeking for a tolerably soft piece of ground. When it has found one, it travels no further, but scratches away with its fore-paws with wonderful power and rapidity, seeming to sink, as it were, into the earth, rather than to excavate a tunnel.
There is an insect well known to entomologists, called the Mole-cricket, because its structure and many of its habits are strangely similar to those of the animal from which it derives its name. At the upper part of the illustration is seen a portion of the fore-foot of the Mole-cricket, and a better implement of excavation can hardly be imagined.
The reader will probably have noticed that in both these creatures the spade, if we may so call it, is not a mere flat plate, but is cleft into several points. It thus answers the purpose of a fork as well as a spade, the several points serving to break up the soil, and the flat palm to throw the earth aside.
This principle is carried out even more fully in the fore-paw of the African Ant-bear, or Aard-vark (Orycteropus Capensis), a figure of which is given in the illustration. This animal is a great excavator, living in burrows of such dimensions that the wild boar is in the habit of making its home in them after they are deserted.
Something more, however, than a digging apparatus is needed for the Ant-bear. This animal feeds almost wholly on the Termites, which it obtains by tearing down the walls of their dwellings. Now, as these wonderful buildings are nearly as hard as brick, and, indeed, are composed of the same materials, it is necessary that the claws of the Ant-bear should be modified so as to be able to break through the walls. Accordingly, they are much more curved than those of the Mole and the Mole-cricket, and so serve for tearing as well as digging, being struck into the wall, and thus pulling it down, just as a labourer breaks down a bank with his mattock.
Indeed, had we wished to extend these analogies still further, we might easily have given the claws of the Aard-vark as a prototype of our English mattock. The same weapons as possessed by the Ant-bear of tropical America are used in exactly the same manner, but are even stronger, and extend to such a length that when the animal walks, it cannot stretch its claws out in front, but is obliged to double them under its feet.