In regard to the general subject, it may be said that we can discern in the primitive adoration of footprints a somewhat advanced stage in the religious thoughts of man. He has got beyond total unconsciousness of God, and beyond totemism or the mere worship of natural objects--trees, streams, stones, animals, etc. He has reached the conception of a deity who is of a different nature from the objects around him, and whose place of abode is elsewhere. He worships the impression of the foot for the sake of the being who left it; and the impression helps him to realise the presence and to form a picture of his deity. That deity is not a part of nature, because he can make nature plastic to his tread, and leave his footmark on the hard rock as if it were soft mud. He thinks of him as the author and controller of nature, and for the first time rises to the conception of a supernatural being. CHAPTER V THE ROMAN FORUM No spot on earth has a grander name or a more imposing history than the Roman Forum. Its origin takes us far back to geological ages--to a period modern indeed in the inarticulate annals of the earth, but compared with which even those great periods which mark the rise and fall of empires are but as the running of the sands in an hour-glass. It opens up a wonderful chapter in the earth's stony book. Everywhere on the site and in the neighbourhood of Rome striking indications of ancient volcanoes abound. The whole region is as certainly of igneous origin, and was the centre of as violent fiery action, as the vicinity of Naples. The volcanic energy of Italy seems to have begun first in this district, and when exhausted there, to have passed gradually to the south, where Vesuvius, Etna, and Stromboli witness to the great furnace that is still burning fiercely under the beautiful land. No spectacle could have been more sublime than that which the Roman Campagna presented at this period, when no less than ten volcanoes were in full or intermittent action, and poured their clouds of smoke and flame into the lurid sky all around the horizon. Up to the foot of the mountains the sea covered the vast plain; and the action of these waves of fire and steaming floods forms a natural epic of the grandest order. Prodigious quantities of ashes and cinders were discharged from the craters; and these, deposited and hardened by long pressure under water, formed the reddish-brown earthy rock called tufa, of which the seven hills of Rome are composed.