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. [Illustration: HEART-URCHIN. DIGGING-STICK.] 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?”