1883.] Thermometric and Hygromeiric Observations. 311 



about 9 a.m. in conjunction with other thermometers at 5 feet above 

 the ground. The readings of these instruments have since that time 

 been published in extenso, but the author has seen no discussion of 

 them, and is not aware whether the thermometers have been verified 

 or not, nor how they are mounted. 



In 1868 Mr. James Glaisher, F.R.S., instituted a series of readings 

 of the dry and wet bulb thermometers at the Royal Observatory, 

 Greenwich, at the respective heights of 4 feet, 22 feet, and 50 feet 

 above the ground. The observations which are published in extenso 

 in the "Proceedings of the Meteorological Society," vol. v, p. 29, 

 extend only from June 25 to August 6 — a period of six weeks during 

 the hottest part of the year. The results show that during the day 

 hours the temperature at 4 feet was at times 7° and 8° higher, and at 

 night 3°, 4°, and 5° lower than at 50 feet above the ground. 



The subject was mentioned at the Meteorological Conference at 

 Leipzig in 1872, and both Messrs. Wild and Scott undertook to have 

 experiments made, with the following results : — 



In 1872-74 Professor H. Wild carried out experiments with 

 thermometers and hygrometers placed at the heights of 6 feet, 52 feet, 

 and 86 feet above the ground on a scaffolding at the Pulkowa 

 Observatory. (" Repertorium fur Meteorologie," vol. v.) 



During 1873-75 readings of maximum and minimum, and dry and 

 wet bulb thermometers were made on behalf of the Meteorological 

 Office at the Kew Observatory, 10 feet, and on the ornamental Pagoda 

 in the Royal Gardens, Kew, at the respective heights of 22 feet, 

 69 feet, and 129 feet above the ground. Mr. R. H. Scott, P.R.S., in 

 concluding his report on these observations (" Quarterly Weather 

 Report," 1876, Appendix 3 ), says : " That so far as the evidence 

 adduced in this paper goes, it indicates that, on the average of a con- 

 siderable series of observations, the influence of height on mean 

 thermometric al and hygrometrical results is not very great, but that 

 on individual occasions very material differences are observed. 



Lastly, Mr. G. Dines has recently communicated to the Meteoro- 

 logical Society (" Quarterly Journal," vol. viii, p. 189), the results 

 of observations which he has made with thermometers placed 4 feet 

 and 50 feet above the ground at his residence at Hersham, Walton-on- 

 Thames. These observations, which extended from September, 1876, 

 to September, 1878, inclusive, show that on the average the mean 

 daily range of temperature at 50 feet was 2°'l less than at 4 feet, the 

 mean of the maxima at 50 feet being 1°*2 lower, and the mean of the 

 minima O- 9 higher than at 4 feet. 



It will be seen from the above abstract that, up to the end of 1881, 

 there was no precise information as to the form of the curve of daily 

 temperature at considerable heights above the ground. It was known 

 that the amplitude of the daily range was materially reduced, but the 



