l] INTRODUCTION 27 



62° F. (16"6° C), the warmest. According to Lees, the average 

 daily range of temperature in the West Riding of Yorkshire 

 (the south-west of which is included in the present district) 

 is about twelve or thirteen degrees F. (7 "2° C.) in the shade, 

 and about thirty-two to thirty-four degrees F. (18'9° C.) under 

 exposure to the direct rays of the sun (Lees, 1888 : 6). These 

 temperatures, it should be remembered, are corrected to sea level, 

 and hence do not show the actual temperatures of the district. 



Phenological observations show that the opening of spring 

 flowers and the unfolding of the leaves of trees is from two to four 

 weeks later on the Pennines than in the lowlands of Somerset, 

 and from ten days to three weeks later than in Cambridgeshire. 



The winter on the Pennine uplands is a long one, lasting, as 

 a rule, from the beginning of November to the beginning of 

 May, though snow does not, as a rule, lie very long on the 

 ground, owing to intervals of mild weather. Although some 

 moorland plants, such as the bilberry (Vaccinium Myrtillus), 

 the crowberry (Empetrum nigrum), and the cotton-grasses 

 {Eriophorum vaginatum and E. angustifolium) flower in late 

 April and early May, the plants of the moorlands make very 

 little new growth before June and July. 



The Upper Atmosphere 



I am indebted to Professor A. Schuster, F.R.S., for kindly 

 supplying me with the reports (Schuster, 1908-9) for the years 

 1908 and 1909 of the investigation of the upper atmosphere 

 conducted by the meteorological department of the Victoria 

 University of Manchester. This investigation was begun on 

 January 1st, 1908. The meteorological station is situated near 

 Glossop, in Long. 1° 57 W. and Lat. 53° 24 N., at a height of 

 335 metres (1100 feet, approx.) above sea level. The details 

 which are here utilized consist of readings of temperature, 

 direction and velocity of the wind, and the humidity of 

 the air, at altitudes respectively of 335 metres (1100 feet), 

 500 metres (1640 feet), and 750 metres (2460 feet). The 

 readings of the higher altitudes were obtained by means of 

 kites and balloons ; and the figures utilized represent only a 

 small proportion of the total number of observations made by 

 Professor Schuster and his staff. 



