The Ascent of Water in Trees.The supply of water to the peripheral protoplasts of a tree is consequently of the first importance.
From the East Turkestan lowlands on the north the ascent is very steep, and the passes across both sets of ranges lie at great altitudes; for example, the pass of Sanju-davan in the lower range is 16,325 ft.
The ascent of Popocatepetl is made on the northeastern slope, where rough roads are kept open by sulphur carriers and timber cutters.
The ascent to the upper plain then becomes very gentle, though there is a rise of 400 or 50o ft., until it reaches the south-eastern portion of Sargent county and changes into the more abrupt Coteau des Prairies, a plateau about 2000 ft.
The ascent of water is most rapid through coarse sands, but the height to which it will rise is comparatively small.
The biggest ascent is that from the Kalta-alaghan to the Arka-tagh, namely, nearly 1850 ft.
The Vaenol slate quarries are here, and hence is the easiest ascent of Snowdon, with a railway to the summit.
The bridle road up the mountain leaves Glen Nevis at Achintee; it has a gradient nowhere exceeding 1 in 5, and the ascent is commonly effected in two to three hours.
To the west of Parr's Ridge the surface for the most part slopes gently down to the east bank of the Monocacy river (which flows nearly at a right angle with the streams east of the Ridge), and then from the opposite bank rises rapidly toward the Catoctin Mountain; but just above the mouth of the Monocacy on the east side of the valley is Sugar Loaf Mountain, which makes a steep ascent of 1250 ft.
The whole of Allamakee and parts of Winneshiek, Fayette, Clayton, Delaware, Dubuque and Jackson counties form the only driftless area of the state; in that section cliffs frequently rise almost vertically from the banks of a river to a height of from 300 to 400 ft., and from the summit of the cliff to the crest of the divide, a few miles distant, there is another ascent of 300 ft.