is not, however, up to the mark of the knowledge of the day, and omits to take notice of the fact that earths can occasionally be converted into gases, and airs converted into liquids or solidified. Instead of their simple system, what is now wanted is something that will take into account the different races of mankind--some progressive, some the reverse--and the different accidents of success and prosperity, or disaster and poverty: the one leading to the aggregation of detached communities into great centres, and consequent progress; the other leading to dispersion and stagnation, if not retrocession, in the arts of life which tend towards what we call civilization. At the International Congress of Prehistoric Archæology, held at Copenhagen in the autumn of 1869, it was understood that many of the best Northern antiquaries were inclined to abandon, to a very considerable extent, the hard and fast lines of their first system, and to admit not only that there may be considerable overlapping, but even, in some instances, that its indications were not in accordance with the facts. More than two years have elapsed since the Congress was held, but the volume containing the account of its proceedings is not yet published; when it is, we may probably be in a position to speak much more favourably not only of their views but of the extent of their knowledge of the antiquities in question. Under these circumstances, we may congratulate ourselves in possessing such a work as that of Sjöborg.[321] He wrote, fortunately, before the Danish system was invented, but, unfortunately, before drawing and engraving had reached the precision and clearness which now characterize them. In consequence of the last defect, we cannot always feel sure of our ground in basing an argument on his drawings; but, generally speaking, he is so honest, so free from system, that there is very little danger in this respect. The work has also the merit of being as free from the speculations about Druids and Serpents which disfigure the contemporary works of English antiquaries, as it is from the three ages of the Danes; though, on the other hand, he relegates all the dolmens and such like monuments to a prehistoric "Joter," or giant race, who preceded, according to his views, Odin and his true Scandinavians, to whom he ascribes all the truly historic monuments.