It is scarcely five in the evening, and, writes a correspondent from Gyantse in a letter dated October 18 to The Englishman," the sun is settling behind a battalion of mountains whose tops are covered with thin layers of snow. Twilight is of very brief duration here, the transition from sunlight to the darkness of the night being complete within less than 50 minutes.
The usual solar halo is conspicnous by its presence. Shafts of green, blue, red and orange lights shoot skywards from the direction of the luminary whose setting announced by that strange anq little understood phenomenon, the Green Flash. or some two or three minutes after actual sunset, the halo quivers in the western sky, soon thereafter mysteriously fading into nothingness, Then the mountains around seem to rear themselves into the giants that they really are, and. become sil-lionetted against a sky of lovely green. It is now that wonderful phenomenon can be seen by all who delight in the mysteries of Nature.
Previous to my arrival here, it was unknown to me, nor have I ever, to my recollection, read any account of it in any scientific work. The phenomenon is very similar to series of rapid dark greenish shafts of light, cone-shaped with their apex lying in the direction of, the vanished sun, appearing to shoot across the horizon from right tu left, and as rapidly disappearing. The apparition lasts from three to five seconds, it has been seen on several occasions, and certain experiments are now being conducted in order to ascertain whether it is an optical illusion or a terrestrial phenomenon. It' is not to be confused with the familiar Green Flash at sunset, for the interval between this latter and the appearance of the mys-. terious shafts is equal to the duration of twilight itself, less some five or ten minutes. The Green Flash is a daily apparition here, both with the rising and setting sun, The altitude of Gyantse, it should be noted, is some 13,500 ft.
Lhe Zodiacal Light was—visible here on the first three evenings of the beginning of October, and on each of these occasions a solar halo formed the back-ground of a truly delightful picture of mountains bathed in a rosy hue, with shafts of blue, green and red lights radiating from the direction of the setting sun, followed by the Green Flash and the disappearance of the Zodiacal Light some three minutes after the sun had set.
The evening sky is alive with stars of all colours and magnitudes, and the Tibetans ought to be more profound astronomers than the Chaldeans of old. The most conspicuous object in the early evening sky, of course, is Venus. I asked several of my servants if they could distinguish ing unusual in the appearance of the planet, but it was obvious to me that nothing was seen by any one of them to call for duy comment.
Text read from the printed page and cleaned; old type leaves the occasional error.