=Iron Weapons.=—­These arms are axes, swords, daggers, and bucklers.  They are ordinarily found by the side of a skeleton in a coffin of stone or wood, for warriors had their arms buried with them.  But they are found also scattered on ancient battle-fields or lost at the bottom of a marsh which later became a turf-pit.  There were found in a turf-pit in Schleswig in one day 100 swords, 500 lances, 30 axes, 460 daggers, 80 knives, 40 stilettos—­and all of iron.  Not far from there in the bed of an ancient lake was discovered a great boat 66 feet long, fully equipped with axes, swords, lances, and knives.

It is impossible to enumerate the iron implements thus found.  They have not been so well preserved as the bronze, as iron is rapidly eaten away by rust.  At the first glance, therefore, they appear the older, but in reality are more recent.

=Epoch of the Iron Age.=—­The inhabitants of northern Europe knew iron before the coming of the Romans, the first century before Christ.  In an old cemetery near the salt mines of Hallstadt in Austria they have opened 980 tombs filled with instruments of iron and bronze without finding a single piece of Roman money.  But the Iron Age continued under the Romans.  Almost always iron objects are found accompanied by ornaments of gold and silver, by Roman pottery, funeral urns, inscriptions, and Roman coins bearing the effigy of the emperor.  The warriors whom we find lying near their sword and their buckler lived for the most part in a period quite close to ours, many under the Merovingians, some even at the time of Charlemagne.  The Iron Age is no longer a prehistoric age.

CONCLUSIONS

=How the Four Ages are to be Conceived.=—­The inhabitants of one and the same country have successively made use of rough stone, polished stone, bronze, and iron.  But all countries have not lived in the same age at the same time.  Iron was employed by the Egyptians while yet the Greeks were in their bronze age and the barbarians of Denmark were using stone.  The conclusion of the polished stone age in America came only with the arrival of Europeans.  In our own time the savages of Australia are still in the rough stone age.  In their settlements may be found only implements of bone and stone similar to those used by the cave-men.  The four ages, therefore, do not mark periods in the life of humanity, but only epochs in the civilization of each country.

=Uncertainties.=—­Prehistoric archaeology is yet a very young science.  We have learned something of primitive men through certain remains preserved and discovered by chance.  A recent accident, a trench, a landslip, a drought may effect a new discovery any day.  Who knows what is still under ground?  The finds are already innumerable.  But these rarely tell us what we wish to know.  How long was each of the four ages?  When did each begin and end in the various parts of the world?  Who