Icicles Formed by Radiation. (General Sir Richard Strachey, _Geographical Journal_, 1900, vol. XV., page 168.)--On the Balch pass of the Balch range in Tibet, General Strachey, in 1848, saw icicles of which he says: "On the rocks exposed to the south were very curious incrustations of ice, icicles indeed, but standing out horizontally like fingers towards the wind. I was not able to understand how they were caused, nor can I tell why they were confined to particular spots. The thermometer stood at 41°[F.], and though the dew point at the time would probably have been below 32°[F.], and the cold produced by evaporation sufficient therefore to freeze water, yet it is evident that no condensation could ever take place simultaneously with the evaporation. * * * It has since occurred to me that these icicles were formed by radiation. I found, subsequently, in a somewhat similar position, that a thermometer suspended vertically, and simply exposed to the sky in front of it, was depressed as much as 20° F. below the true temperature of the surrounding air. This result was, of course, due to the radiation through the extremely dry and rarefied atmosphere at the great elevation at which the thermometer was exposed. As radiation takes place freely from a surface of ice, the growth of such icicles as those described might be due to the condensation of vapour brought up by the southerly day winds that so constantly blow over these passes, and its accumulation in the form of ice on the exposed extremity of the icicle, the temperature of which might thus have been greatly reduced." INDIA. Ice Formed by Radiation. (T. A. Wise, _Nature_, vol. V., page 189; R. H. Scott, _Elementary Meteorology_, Third Ed., pages 61, 62.)--Mr. Bunford Samuel called my attention to the mode of manufacturing ice by radiation in India. It is as follows:-- "A very practical use of nocturnal radiation has been made from time immemorial in India in the preparation of ice, and on such a scale that about 10 tons of ice can be procured in a single night from twenty beds of the dimensions about to be given, when the temperature of the air is 15° or 20° [F.] above the freezing point. * * * The locality referred to is the immediate neighborhood of Calcutta. A rectangular piece of ground is marked out, lying east and west, and measuring 120 by 20 feet. This is excavated to the depth of two feet and filled with rice straw rather loosely laid, to within six inches of the surface of the ground. The ice is formed in shallow dishes of porous earthenware, and the amount of water placed in each is regulated by the amount of ice expected. "In the cold weather, when the temperature of the air at the ice fields is under 50°, ice is formed in the dishes. The freezing is most active with N. N. W. airs, as these are driest; it ceases entirely with southerly or easterly airs, even though their temperature may be lower than that of the N. N. W. wind.