This argument will be appreciated by those who duly consider, on the one hand, that if man were on the earth in those pre-Adamic ages, it is in the highest degree improbable that his population ranged at a dozen for the area of all France, and a few hundreds only to a continent――for what should forbid him as well as the lower animals to “be fruitful and multiply and replenish the earth”? Besides, a population so sparse and consequently weak could have made no stand against armies of hyenas, leopards, bears and lions.――――On the other hand, the occurrence of human bones, in numbers so very few and so remote from each other, will be much more rationally accounted for by the possibilities above indicated. Yet let it be understood:――The way is open for any extent of further investigation. We have no occasion to fear the result of the search. Let the rocks be torn up and examined; let mountains be tunneled and canals be dug; let railroad grading go where it will; if the human skeleton should be found where none of these or similar possibilities admit its date since Adam, we will certainly give the case all due consideration and weight. (B.) Next is the argument _from man’s work and from his tools_. Here a larger field opens. My limits scarcely allow me to do more than indicate briefly the present state of the question.――――Thus far explorations have been mostly restricted to Northern and Western Europe, say north of the Alps and of ancient Greece, in the regions anciently known as Gaul, Germany, Scandinavia and Britain. The supposed remains of man’s tools and work are found chiefly in caves and lake-dwellings, or under drift, and only to a small extent in monuments above the present surface. The lake-dwellings specially referred to are in Switzerland, where during the very dry winter of 1853–4 several remarkable villages were found built on piles below, the present average watermark, which were once without doubt the abodes of men, with quite abundant traces indicating their modes of life, civilization, implements, and the contemporary animal races.[13] The various stages of civilization developed in these ancient remains have been usually classified under three heads: 1. The _Stone age_, in which man’s cutting implements, working tools and weapons of war, were of stone. This age is sometimes subdivided, the older part being called “Palaeolithic” [old stone], and the more recent, “Neolithic” [new stone]. 2. The _Bronze age_, its implements being chiefly of copper or brass. 3. The _Iron age_, where iron first appears. Now the great question――the only one that comes within our range of inquiry――is the _date_ of these traces of ancient men. When did the men of the Stone age and of the Bronze and the Iron age live?