We have no concern with any operations on land; it is enough for our purpose to add that after spending some time in making repairs to those ships which remained, Cæsar took his ships and men back to Boulogne. The expedition had proved a failure. But in the following year Cæsar again invaded Britain. This time he set forth neither from Boulogne nor Ambleteuse, but from Wissant, which is about midway between the chalk cliffs of Cape Blanc Nez and the sandstone cliffs of Cape Gris Nez, and on the charts of to-day you will still find “Cæsar’s Camp” marked. Wissant was much nearer to the British coast than either of the other two ports, and the Roman evidently was not anxious to make the cross-Channel passage any longer than need be this time. The fleet at Boulogne had been weather-bound for three weeks with a series of north-west winds. Anyone who has sailed along this portion of the French coast knows what a nasty sea a wind from that direction sets up, blowing as it does directly on shore. A north-west wind would have sent a strong swell into Boulogne harbour; but apart from that, even had the ships been at Wissant ready to start it would not have been of much avail, for the course from there to the nearest British shore was about north-west—a dead “nose-ender.” June, therefore, came and went.

But about July 6, Cæsar set sail from Wissant about sunset. As the wind was light from the south-west he had a favourable air. There was no moon, but the nights are warm and not very dark at the beginning of July. The tide probably set him down some distance in the vicinity of Gris Nez, for it did not begin to flow to the north-east till 10 p.m. Good progress was made this time, and by midnight the leading division was getting well up to the South Foreland. The wind, as it so often does on a July night, began to fail and finally dropped utterly, so that the fleet had barely steerage way. The strong Channel flood took hold of them, and about 3.15 a.m. Cæsar was abreast of Kingsdown (a little to the south of Walmer). Eventually he arrived at Sandwich about noon, having no doubt anchored for six hours, since the Channel tide was just about to run to the south-west when he had got to Kingsdown. This time he left his 600 ships not hauled up on the beach, but at anchor, having disembarked his troops. Yet once more a storm rose which caused some of the vessels to part their anchors, others to collide with each other, and others still to be dashed ashore and damaged. Forty were totally destroyed, but the remainder he managed to patch well enough. They were hauled ashore, probably by means of windlasses or capstans, greased rollers being inserted under the keels. They were then surrounded by earthworks so as to be protected efficiently. About the middle of September and about nine o’clock at night, Cæsar and his fleet once more returned from Britain and arrived at Boulogne about daybreak.

He took back with him a great deal of invaluable information on the subject of tides, but the cost of obtaining such knowledge had been by no means small. It is possible that a critical reader may feel disposed to remark that the Channel tides in Cæsar’s time were not identical in direction and force with those of to-day. It is impossible to settle the point with accuracy. Certain it is that for some centuries the coast between Sandgate and Dover has altered a good deal, but, speaking generally, this has not been of much consequence, though a good deal of alteration has taken place between Hythe and Dungeness, which may or may not have affected the tidal stream. Similarly, it is a matter for dispute whether the Channel stream in the neighbourhood of the Dover Straits began to ebb and flow at precisely the same time as to-day. It is more than possible that the changes in the configuration of the coast and of the Goodwin Sands may, during the centuries, have modified the Channel tides hereabouts. Some say that in Cæsar’s time Thanet was an island, that Dungeness did not exist, that Romney Marsh was covered at high water by an estuary 50,000 acres in extent, and that the estuary of the Thames was far wider than to-day. But even when all these points have been taken into consideration, two facts remain true: that the tide ebbed and flowed backwards and forwards along the English Channel, and that because of the narrow neck through which this huge volume of water has to rush by the Straits of Dover there must have been not much difference in strength from that which is experienced to-day.

The geographical information which Cæsar brought back concerning Gaul and Britain after his campaigns cannot be lightly regarded. It was the knowledge which an explorer bestows on a wondering community. Such items as prevailing winds, tides, currents, the influence of moon and the nature of harbours along the coast, the depths of water, and so on, might have been appreciated still more had the Romans been as eager for scientific knowledge as they were for organisation and conquest.

But if the Romans were not great navigators nor even a race of seamen, at any rate they were very fine shipwrights. Expert opinion of to-day, arguing from the evidence of the only Roman craft which are still in existence, gives the highest praise to the art of the Roman shipbuilder. The relics of the craft found in Lake Nemi were discussed by me in another volume,[16] and need be referred to now only slightly. But the other craft which was recently unearthed whilst excavations were being made in 1910 at Westminster, on the site for the new London County Council Hall, is far more instructive, because being above ground it is get-at-able and capable of intimate study. It now lies among the collection of the London Museum in Kensington Gardens. This craft was probably one of the fleet of Carausius, who for a time was admiral under Maximilian and Diocletian, but subsequently rebelled against the Imperial authority and proclaimed himself emperor of Britain in A.D. 287.

Ship of the Roman Period discovered at Westminster.

Sketch showing the Interior of Hull.

This boat was found lying on a shell sand which indicated the original bed of the Thames. The date is approximately fixed by the three coins which were found with the boat: one of Tetricus the Elder in Gaul (A.D. 268–273), the second of Carausius in Britain (A.D. 286–293), and the third of Alectus in Britain (A.D. 293–296). It is possible that there was some ceremony in placing coins in a Roman boat, just as to-day coin of the realm is placed at the laying of a foundation-stone.

She was probably a single-decked war-galley, built in Gaul, but had been dismantled before being abandoned to sink in the waters of the Thames. One expert naval architect, who made a careful inspection of this relic when first discovered, has gone so far as to state that not only is the craftsmanship excellent, that probably nothing built in our own time would look so well after seventeen hundred years’ immersion, but that finer fitting could not be expected to-day. It shows, further, not merely good workmanship, but good design.