But these are speculations which may or may not be verified by future research. For the present we must be content with the fact that, in spite of the philological evidence to the contrary, copper, and not bronze, was the metal which preceded the use of iron in Babylonia, whereas in the northern kingdom of Assyria bronze was already known at a comparatively early date. So far as the existing evidence can carry us, it seems to indicate that Babylonia was the primitive home of the copper industry, while bronze, on the other hand, made its way eastward from Asia Minor and the north of Syria. Where bronze was first invented is still unknown to us; all that seems certain is that it must have been in a land where copper and tin are found together. NOTE According to the mineralogists, in the western part of the northern hemisphere tin is found only in Britain, Spain and the neighbourhood of Askabad, the scanty surface-tin of Saxony, France and Tuscany being too poor and insignificant to have attracted attention in antiquity (see de Morgan, _Mission Scientifique au Caucase_, ii. pp. 16–28). The American excavations at Askabad under Professor Pumpelly appear to have made it clear that bronze was not invented in that part of the world, or indeed used in early days, and we are thus thrown back on Britain and Spain. It is quite certain, however, that bronze made its way to the west of Europe from the east, and the Hon. John Abercromby has proved (_Journal of the Anthropological Institute_, xxxii. pp. 375–94, and _Proceedings of Society of Antiquaries of Scotland_, 1903–4, pp. 323–410) that the bronze culture came to this country from the valley of the central Rhine where it cuts the river at Mayence. On the other hand, the bronze-age civilization of the Danube valley, the Balkan peninsula and Italy forms a whole with that of the south-eastern basin of the Mediterranean, which again is closely connected with the bronze-age culture of the Ægean, Asia Minor and Egypt, while the civilization of the Danube valley leads on to that of Central Europe and, to a less extent, of Scandinavia and Northern Germany. Montelius (_Journal of the Anthropological Institute_, 1900, pp. 89 _sqq._) has pointed out that the early bronze culture of Northern Italy was carried to Scandinavia along the route of the amber trade as far back as the close of the neolithic age in Sweden, and the numerous objects of Irish gold found in Scandinavia--though, it is true, of somewhat later date--show that commercial relations must have existed between the British Islands and the Scandinavian peninsula. Tin might have followed the gold route until it met the amber route, by which it would have been carried southward to Central Europe and the Adriatic.