Chorparun, at the top of the Dunwah pass, is situated on an extended barren flat, 1320 feet above the sea, and from it the descent from the table-land to the level of the Soane valley, a little above that of the Ganges at Patna, is very sudden. The road is carried zizgag down a rugged hill of gneiss, with a descent of nearly 1000 feet in six miles, of which 600 are exceedingly steep. The pass is well wooded, with abundance of bamboo, _Bombax, Cassia, Acacia,_ and _Butea,_ with _Calotropis,_ the purple Mudar, a very handsome road-side plant, which I had not seen before, but which, with the _Argemone Mexicana,_ was to be a companion for hundreds of miles farther. All the views in the pass are very picturesque, though wanting in good foliage, such as _Ficus_ would afford, of which I did not see one tree. Indeed the rarity of the genus (except _F. infectoria_) in the native woods of these hills, is very remarkable. The banyan and peepul always appear to be planted, as do the tamarind and mango. Dunwah, at the foot of the pass, is 620 feet above the sea, and nearly 1000 below the mean level of the highland I had been traversing. Every thing bears here a better aspect; the woods at the foot of the hills afforded many plants; the bamboo (_B. stricta_) is green instead of yellow and white; a little castor-oil is cultivated, and the Indian date (low and stunted) appears about the cottages. In the woods I heard and saw the wild peacock for the first time. Its voice is not to be distinguished from that of the tame bird in England, a curious instance of the perpetuation of character under widely different circumstances, for the crow of the wild jungle-fowl does not rival that of the farm-yard cock. In the evening we left Dunwah for Barah (alt. 480 feet), passing over very barren soil, covered with low jungle, the original woods having apparently been cut for fuel. Our elephant, a timid animal, came on a drove of camels in the dark by the road-side, and in his alarm insisted on doing battle, tearing through the thorny jungle, regardless of the mahout, and still more of me: the uproar raised by the camel-drivers was ridiculous, and the danger to my barometer imminent. We proceeded on the 11th of February to Sheergotty, where Mr. Williams and his camp were awaiting our arrival. Wherever cultivation appeared the crops were tolerably luxuriant, but a great deal of the country yielded scarcely half-a-dozen kinds of plants to any ten square yards of ground. The most prevalent were _Carissa carandas, Olax scandens,_ two _Zizyphi,_ and the ever-present _Acacia Catechu._ The climate is, however, warmer and much moister, for I here observed dew to be formed, which I afterwards found to be usual on the low grounds. That its presence is due to the increased amount of vapour in the atmosphere I shall prove: the amount of radiation, as shown by the cooling of the earth and vegetation, being the same in the elevated plain and lower levels.* [See Appendix C.]