among the lower animals of a near approach to the principle involved in the use of tools--that is to say, the use of natural force through artificial means. Thus the common gray or hooded crow is constantly in the habit of lifting shell-fish to a certain height in the air and then letting them fall upon the rocks of the shore in order to break the shells. Some species of monkey will even use any stone which may be at hand for the purpose of striking and breaking a nut. The elephant tears branches from the trees and uses them as an artificial tail to fan himself and to keep off the flies. But between these rudiments of intellectual perception and the next step--that of adapting and fashioning an instrument for a particular purpose--there is a gulf in which lies the whole immeasurable distance between man and the brutes. In no case whatever do they ever use an implement made by themselves as an intermediate agency between their bodily organs and the work which they desire to do. Man, on the contrary, is so constructed that in almost everything he desires to do he must employ an agency intermediate between his bodily organs and the effect which he wishes to produce. But this necessity, which in one aspect is a physical disability, is correlated with a mind capable of invention, and with certain implanted instincts which involve all the rudiments of mechanical skill. The man who first lifted a stone and threw it, practiced an art which not one of the lower animals is capable of practicing. This is an act which in all probability is as strictly instinctive and natural to man as it is to a dog to bite, or to a bull to charge. Yet the act involves the idea and the knowledge of projectile force and of the arts by which direction can be given to that force. The wielding of a stick is, in all probability, an act equally of primitive intuition, and from this to the throwing of a stick, and the use of javelins, is an easy and natural transition. Simple as these acts are, they involve both physical and mental powers capable of all the developments which we see in the most advanced industrial arts.