The village of Nankow is at the entrance of the mountain pass of that name. It is for this pass alone that the mule-litters are necessary, for it would be impossible to take any wheeled carriage through. In a Russian sketch of the route from Peking to Kiachta, it is stated that the road is passable for carriages throughout. There are several very difficult rocky passes on the road, but this one at Nankow is, I am certain, impracticable for carriages. [Illustration: THE NANKOW PASS. (Page 63.)] On the 18th August, early in the morning, we entered the defile. It is indeed a terrible road, over huge boulders of rock. The pass is about thirteen miles in length, and for the greater part of that distance nothing breaks the monotony of the precipitous mountain wall on either side. The remains of several old forts are seen in the pass, showing the importance that has been attached to it in former times. It certainly is the key of the position, and the last step of an invader towards Peking. But it is so well defended by nature, that a handful of men could keep an army at bay, if any were so bold as to attempt to force this thirteen miles of defile. The care bestowed on the defences hereabouts shows the terror inspired by the Mongols and other outer tribes in the hearts of the rulers of China. Our mules struggled gallantly with their loads, slipping and tripping at every step, and landed us at the outside of the pass, without accident of any kind, but not without a good deal of wear and tear of hoof. They even kept up almost their full travelling pace of three miles an hour. At the northern exit from the pass a branch of one of the inner "Great Walls" crosses. It is out of repair, but still the archway over the port is good, and it would puzzle anyone to get in or out of the pass without going through the gate.