Another type, known as the "hop pole" bridge is made of slightly heavier poles which are tied together in threes so as to form isosceles triangles. Each triangle forms one trestle. The two poles which form the sides project a little above the apex so that in fact we have an isosceles triangle with a V at the apex. To the root of the V another pole is tied loosely and the whole trestle is pushed feet first into the water. Then, by pushing the pole, it is forced into an upright position in which it is secured by the pole being firmly fixed to the shore and strongly lashed to the root of the V where, before, it was only loosely tied. A second trestle is then in like manner fixed in front of the first one, connected to it by a pole just as the first is connected to the bank. And so the thing grows. To all the upper ends of the V's a light pole is tied to form a handrail. In this case, of course, the floor of the bridge is nothing more than a pole, but with the assistance of a handrail it is quite easy to walk along a single pole. And that reminds me of a simple type of suspension bridge which, an engineer officer once assured me, is actually copied from one habitually made by some of the Indian natives. It consists of three ropes upon one of which you walk, while the other two form a handrail upon either side. The three ropes are held at intervals in their correct relative positions by little wooden frames formed of three sticks tied together, one rope being tied to each corner of each triangle. On the banks stakes are driven in and tied back with cords to give additional strength, and to them the ends of the ropes are secured. One drawback to this form of bridge is that the ropes are naturally far from level and one has to walk down a steep hill to commence with and up again at the other end. I once saw a specimen of this kind of bridge across a wide ditch, a part of the old defences of Chatham, and an elderly gentleman who was with me, a man of considerable proportions, insisted upon trying it for himself. He took but a step or two when his foot began to slide downhill along the foot rope faster than he dare move his hands along the hand ropes, with the result that he was very soon in a very uncomfortable position. Thus he remained, to the amusement of all his friends, until two stalwart Royal Engineers came to his aid and "uprighted" him. In crossing a swamp something in the nature of a bridge is sometimes required. Canvas laid upon branches often makes a good road over what would otherwise be impassable.