PORTABLE INCLINES USED IN ABYSSINIA.
Abyssinian mule platforms.
Mr. Percival, who has travelled much in Abyssinia, tells us that he used what he calls portable inclines to facilitate the passage of his long and heavily-laden mule trains over difficult places, especially such as the perpendicular edges of stratified rock 2ft. or 3ft. in thickness, which to laden mules would be as impassable as precipices of a thousand times the height. To obviate this difficulty, he employed one or more mules in carrying roughly-made platforms of stout poles about 10ft. long, with others lashed across them, ladder fashion, so as to present a surface of about 10ft. by 2ft. It would be the duty of the drivers of these mules to have, at least, one of them well to the front in anticipation of any difficulty; the platform would then be laid down, the train would walk over it and pass on, leaving it in the rear to be loaded up again and brought on, while one of the other platform mules would pass to the front in order to be ready for the next difficulty.
The length of these would depend on the height of ledge of rock to be mounted. Suppose the strata were 3ft. in thickness, then a platform of 4ft. 6in. would present a surface lying at an angle of 45°, while one of 7ft. 6in. would lie at 22°; this, for short distances, would not be at all a difficult incline either to descend or to climb, and platforms of 10ft. would give plenty of spare end to rest on the supporting edges, and would not be very inconvenient in carriage. Mr. Percival says he has made them of wattled or hurdle work from 12ft. or 15ft. up to 24ft. in length, and yet so light that one mule has carried two of them; and in following what are called the torrent roads, at the bottom of deep ravines, these would come into requisition at every few hundred yards.
It was in such ravines as these that most disastrous events were anticipated by travellers who knew the difficulties of the country, without being at the same time aware of the skill and resources of our military engineers.
In native warfare an army might be watched into a place from which escape is hopeless, and in the dry season the grass would be then fired at the entrance and the exit; or in the rains, some small river might be partially dammed up so as to accumulate a quantity of water, which being let loose at the proper moment by the dragging out of a pole that serves as a trigger to let go the rest of the impediments, would sweep down upon and overwhelm the helpless enemy.
Natural bridges.
Leaping poles.
Makeshift ladders.