Of the many fields of enquiry opened out by the immense mental activity of this century, there is none which promises to be more fruitful than that which has been won by the joint labours of the geologist, the biologist, and the student of prehistoric archæology. The geologist, beginning his story of the earth at the time when the rains first descended and the seas first began to beat on the coast lines, has laid as it were on a map before us the revolutions in climate and geography that it has undergone. He tells us of continents submerged, and of ocean bottoms lifted up into mountains, and that more rapidly than was formerly supposed, and he points out to us that side by side with the ever-changing conditions of life there were everchanging living forms. Group after group pass before the field of vision, each connected with that which preceded it, and each bearing more and more highly differentiated features until man, “Homo sapiens,” appears, the last born, as well as the highest and noblest of creatures. This has been the work of the biologist; while the prehistorian in the meanwhile has raised the study of man's early work and industries to the rank of a science by the use of a purely inductive method, and has accumulated materials which enable us to establish a fairly complete sequence of events, and as fresh discoveries are continually being made, this sequence becomes more and more complete from the earliest dawn of man's intellect to the foreground of the borders of history.