The temperature at this elevation, between 1 and 3 p.m., varied from 38° to 59°; the mean being 46·5°, with the dew-point 34·6°. The height I made 17,585 feet by barometer, and 17,517 by boiling-point. I tried the pulses of eight, persons after two hours’ rest; they varied from 80 to 112, my own being 104. As usual at these heights, all the party were suffering from giddiness and headaches.

Throughout September various parties passed my tent at Momay, generally Lamas or traders: the former, wrapped in blankets, wearing scarlet and gilt mitres, usually rode grunting yaks, which were sometimes led by a slave-boy or a mahogany-faced nun, with a broad yellow sheep-skin cap with flaps over her ears, short petticoats, and striped boots. The domestic utensils, pots, pans, and bamboos of butter, tea-churn, bellows, stools, books, and sacred implements, usually hung rattling on all sides of his holiness, and a sumpter yak carried the tents and mats for sleeping. On several occasions large parties of traders, with thirty or forty yaks[[259]] laden with planks, passed, and occasionally a shepherd with Tibet sheep, goats, and ponies. I questioned many of these travellers about the courses of the Tibetan rivers; they all agreed[[260]] in stating the Kambajong or Chomachoo liver, north of the Lachen, to be the Arun of Nepal, and that it rose near the Ramchoo lake (of Turner’s route). The lake itself discharges either into the Arun, or into the Painomchoo (flowing to the Yaru); but this point I could never satisfactorily ascertain. The weather at Momay, during September, was generally bad after 11 a.m.: little snow or rain fell, but thin mists and drizzle prevailed; less than one inch and a half of rain was collected, though upwards of eleven fell at Calcutta, and rather more at Dorjiling. The mornings were sometimes fine, cold, and sunny, with a north wind which had blown down the valley all night, and till 9 a.m., when the south-east wind, with fog, came on. Throughout the day a north current blew above the southern; and when the mist was thin; the air sparkled with spiculæ of snow, caused by the cold dry upper current condensing the vapours of the lower. This southern current passes over the tops of the loftiest mountains, ascending to 24,000 feet, and discharging frequent showers in Tibet, as far north as Jigatzi, where, however, violent dry easterly gales are the most prevalent.

[259] About 600 loaded yaks are said to cross the Donkia pass annually.

[260] One lad only, declared that the Kambajong river flowed north-west to Dobtah and Sarrh, and thence turned north to the Yaru; but all Campbell’s itineraries, as well as mine, make the Dobtah lake drain into the Chomachoo, north of Wallanchoon; which latter river the Nepalese also affirm flows into Nepal, as the Arun. The Lachen and Lachoong Phipuns both insisted on this, naming to me the principal towns on the way south-west from Kambajong along the river to Tingri Maidan, via Tashirukpa Chait, which is north of Wallanchoon pass.

The equinoctial gales set in on the 21st, with a falling barometer, and sleet at night; on the 23rd and 24th it snowed heavily, and being unable to light a fire at the entrance of my tent, I spent two wretched days, taking observations; on the 25th it cleared, and the snow soon melted. Frosty nights succeeded, but the thermometer only fell to 31° once during the month, and the maximum once rose to 62·5°. The mean temperature from the 9th to the 30th September was 41·6°,[[261]] which coincided with that of 8 a.m. and 8 p.m.; the mean maximum, 52·2°, minimum, 34·7°, and consequent range, 17·5°.[[262]] On seven nights the radiating thermometer fell much below the temperature of the air, the mean being 10·5° and maximum 14·2°; and on seven mornings the sun heated the black-bulb thermometer considerably, on the mean to 62·6° above the air; maximum 75·2°, and minimum, 43°. The greatest heat of the day occurred at noon: the most rapid rise of temperature (5°) between 8 and 9 a.m., and the greatest fall (5·5°), between 3 and 4 p.m. A sunk thermometer fell from 52·5° to 51·5° between the 11th and 14th, when I was obliged to remove the thermometer owing to the accident mentioned above. The mercury in the barometer rose and fell contemporaneously with that at Calcutta and Dorjiling, but the amount of tide was considerably less, and, as is usual during the equinoctial month, on some days it scarcely moved, whilst on others it rose and fell rapidly. The tide amounted to 0·062 of an inch.

[261] The result of fifty-six comparative observations between Calcutta and Momay, give 40·6° difference, which, after corrections, allows 1° Fahr. for every 438 feet of ascent.

[262] At Dorjiling the September range is only 9·5°; and at Calcutta 10°.

On the 28th of the month the Singtam Soubah came up from Yeumtong, to request leave to depart for his home, on account of his wife’s illness; and to inform me that Dr. Campbell had left Dorjiling, accompanied (in compliance with the Rajah’s orders) by the Tchebu Lama. I therefore left Momay on the 30th, to meet him at Choongtam, arriving at Yeumtong the same night, amid heavy rain and sleet.

Autumnal tints reigned at Yeumtong, and the flowers had disappeared from its heath-like flat; a small eatable cherry with a wrinkled stone was ripe, and acceptable in a country so destitute of fruit.[[263]] Thence I descended to Lachoong, on the 1st of October, again through heavy rain, the snow lying on the Tunkra mountain at 14,000 feet. The larch was shedding its leaves, which turn red before they fall; but the annual vegetation was much behind that at 14,000 feet, and so many late flowerers, such as Umbelliferæ and Compositæ, had come into blossom, that the place still looked gay and green: the blue climbing gentian (Crawfurdia) now adorned the bushes; this plant would be a great acquisition in English gardens. A Polygonum still in flower here, was in ripe fruit near Momay, 6000 feet higher up the valley.

[263] The absence of Vaccinia (whortleberries and cranberries) and eatable Rubi (brambles) in the alpine regions of the Himalaya is very remarkable, and they are not replaced by any substitute. With regard to Vaccinium, this is the more anomalous, as several species grow in the temperate regions of Sikkim.