After all, I cannot but take notice of two things with regard to the Wall, that have given me great matter of speculation. The first is, why it was made at all, for it could never be a proper defence, and perhaps at Bowness less than at any other place, since our barbarian forefathers on the north side could pass over at low water, and if the sea was higher or deeper than it is now, could make their attacks from the north-east side by land.—The second is, why the Scots historians, vain enough by nature, have not taken more pains to describe the Wall, a performance which did their ancestors more honour than all the trifling stories put together which they have transmitted to us. It is true the Romans walled out humanity from us; but it is as certain they thought the Caledonians a very formidable people, when they at so much labour and cost built this Wall; as before they had made a Vallum between the Forth and the Clyde. [Sidenote: THE BARRIER NOT A NAKED WALL.] The Romans did not oppose to the enemy a single line of fortification only, which, by some casual negligence on their part, or a sudden exertion of desperate bravery on the side of their antagonists, might in a moment be rendered useless. In addition to the Wall, stationary camps were planted along its whole course, at a few miles distance from it, both to the north and the south; so that, in reality, a triple line of fortresses was opposed to the passage of an enemy from either quarter. These subsidiary stations were connected with the garrisons on the Wall, and to some extent with each other, by good roads. In maintaining a surveillance over an enemy, whether to the north or the south of the chief member of the fortification, in furnishing a secure retreat for the soldiery when venturing beyond their line, and in stemming the first shock of an onset, the importance of the out-stations cannot be over-rated. [Sidenote: THE SUPPORTING FORTS OF DIFFERENT ERAS.] It is not contended that all the stations which are immediately on the north and south of the Wall were erected with the express view of supporting it. Several of them doubtless were, but others, there is reason to believe, were made by Agricola, before the Wall was projected or thought of. All that is necessary for us to admit is, that they contributed materially to the strength of the main structure, and as such, formed an important element in the calculations of the engineer of the Wall.