Thomsen was the first to perceive typologies of grave goods, grave types, methods of burial, pottery and decorative motifs, and to assign these types to layers found in excavation. His published and personal advice to Danish archaeologists concerning the best methods of excavation produced immediate results that not only verified his system empirically but placed Denmark in the forefront of European archaeology for at least a generation. He became a national authority when C.C Rafn, secretary of the "Kongelige Nordiske Oldskriftselskab" ("Royal Society of Northern Antiquaries"), published his principal manuscript in "Ledetraad til Nordisk Oldkyndighed" ("Guide to Scandinavian Archaeology") in 1836. The system has since been expanded by further subdivision of each era, and refined through further archaeological and anthropological finds. It was to be a full generation before British archaeology caught up with the Danish. When it did, the leading figure was another multi-talented man of independent means: John Lubbock, 1st Baron Avebury. After reviewing the Three-age System from Lucretius to Thomsen, Lubbock improved it and took it to another level, that of cultural anthropology. Thomsen had been concerned with techniques of archaeological classification. Lubbock found correlations with the customs of savages and civilization. In his 1865 book, "Prehistoric Times", Lubbock divided the Stone Age in Europe, and possibly nearer Asia and Africa, into the Palaeolithic and the Neolithic: By "drift" Lubbock meant river-drift, the alluvium deposited by a river. For the interpretation of Palaeolithic artifacts, Lubbock, pointing out that the times are beyond the reach of history and tradition, suggests an analogy, which was adopted by the anthropologists. Just as the paleontologist uses modern elephants to help reconstruct fossil pachyderms, so the archaeologist is justified in using the customs of the "non-metallic savages" of today to understand "the early races which inhabited our continent." He devotes three chapters to this approach, covering the "modern savages" of the Indian and Pacific Oceans and the Western Hemisphere, but something of a deficit in what would be called today his correct professionalism reveals a field yet in its infancy: Perhaps it will be thought ... I have selected ... the passages most unfavorable to savages. ... In reality the very reverse in the case. ... Their real condition is even worse and more abject than that which I have endeavoured to depict.