mounting them in a wooden handle; and axes made in this way, by grinding the edge of a suitable pebble, and fixing it in a withe handle, are known in Australia. Moreover, the class to which this almost natural instrument belongs, that, namely, which has a double-convex cross section, is far more numerous and universally distributed than the double-flat, concavo-convex, triangular, or other forms.
Where artificially shaped celts are found only chipped over, in high Stone Age deposits, as in Scandinavia, they are generally to be considered as unfinished; but when celts of hard stone are found only ground near the edge, and otherwise left rough from chipping, they may be taken as denoting a rude state of art. Thus flint celts ground only near the edge are found in Northern Europe, and even in Denmark: but in general celts of the hardest stone are found, during the Ground Stone Age, conscientiously ground and polished all over, and every large celt of hard stone which is finished to this degree represents weeks or months of labour, done not so much for any technical advantage, as for the sake of beauty and artistic completeness.
The primitive hammer, still used in some places, is an oval pebble, held in the hand. Above this comes the natural pebble, or the artificially shaped stone, which is grooved or notched to have a bent withe fastened round it as a handle, as our smiths mount heavy chisels. Above this again is the highest kind, the stone hammer with a hole through it for the handle. This is not found out of the Old World, perhaps not out of Europe; and even the Mexicans, who in many things rivalled or excelled the stone- workers of ancient Europe, do not seem to have got beyond grooving their hammers. The stone axe proper, as distinguished from the mere celt by its more complex shape, and by its being bored or otherwise fitted for a handle, is best represented in the highest European Stone Age, and in the transition to the Bronze Age.
Special instruments and varieties are of great interest to the Ethnographer, as giving individuality to the productions of the Stone Age of different times and places. Thus, the rude triangular flakes of obsidian with which the Papuans head their spears are very characteristic of thoir race. These spears were
