The Temperature Conditions within Clouds

Abstract

AT the meeting of the British Association for the Advancement of Science held in Winnipeg last August, a paper was read before the Physics Section by Prof. A. Lawrence Rotch, director of the Blue Hill Observatory, in which a rise of temperature was described as having been recorded by a ballon-sonde meteorograph in passing through a cloud. In the discussion which followed considerable doubt was expressed as to the possibility of such a condition existing. That there was an increase in temperature recorded by the meteorograph as it passed upward through the cloud there can be no doubt (see diagram in Meteorologische Zeitschrift, December, 1909, p. 554). Dr. John Aitken, in NATURE of November 18, 1909, says that he sees no reason to question the truth of the record, for he has on numerous occasions observed similar increases of temperature while enveloped in a cloud upon the summit of a mountain. He directs attention to the fact that great caution must be exercised in obtaining temperatures under these conditions, for, on account of the excessive radiation that occurs within the cloud, unless the instrument is sufficiently insulated from the heat rays, the thermogram will be vitiated. In the case of the ascent referred to, the increase of temperature was not unreal, for due precaution, in the form of an especially prepared insulator, had been taken to eliminate the effects of radiation, and the ventilation was sufficient.