60 SCIENTIFIC SURVEY OF NOTTINGHAM AND DISTRICT 



piling the table. On the other hand, since only seven such days were 

 recorded in Nottingham during the selected period of 35 years, it is 

 obvious that the gentlest drift of air has been recorded throughout as a 

 wind. 



Of great interest are the observations made by Mr. A. B. Tirm, whose 

 exhaustive analysis of local climatic data has been mentioned, indicating 

 the mean maximum temperatures accompanying winds from different 

 directions. Thus, over a period of 20 years, the maximum air temper- 

 ature reached with a south-westerly wind in the month of January is as 

 high as 47° F., but is only 36° F. with a north-east wind. 



Humidity 



Detailed figures for the relative humidity of the atmosphere are not 

 available for stations in Nottinghamshire, though Cranwell in Lincoln- 

 shire (some 28 miles east-north-east of Nottingham) is one of the twelve 

 stations selected by the Meteorological Office to represent the normals of 

 this element of the weather. There are many occasions during the 

 course of a year when the conditions of humidity at Cranwell 

 approximate closely to those at Nottingham. 



As with all the other stations, Cranwell shows a high humidity prevail- 

 ing during the autimm and winter months. This reaches a maximum in 

 December during which only for a short period daily, i.e. for an hour or 

 two following midday, is the humidity under 90%. No station, however, 

 not even Valencia or Eskdalemuir, experiences such a long period of 

 persistently high humidity, and the autumn period as a whole provides a 

 higher humidity throughout the day at Cranwell than at any other station. 

 Similarly, no station records such a high average maximum humidity 

 (more than 96%) as occurs in the early mornings, 3 a.m. till 7 a.m., in 

 March. Humidity is lowest, as at most places, during the early after- 

 noons of the summer months. At Cranwell however, where it is under 

 68% in May and July, it is never so low as at Kew (58%) or at Lympne 

 (64%) in July. 



The mean annual range of humidity is normally greater in the eastern 

 districts of the British Isles than in the westernmost parts, and greater at 

 inland stations than at the coast. Consequently Cranwell, like Notting- 

 ham, having an eastward interior situation, shows a considerable range, 

 actually twice as great as that of Valencia. 



Rainfall 



The rainfall map of Nottinghamshire (inset opposite page 62) has been 

 constructed from the records of 53 stations within the county, the great 

 majority of which possess readings complete for the standard period 

 1881-1915 and are distinguished in ' British Rainfall ' as first class stations. 

 The map published by H. Mellish in 1893 was based upon the records of 

 only nineteen stations within the county though as many as forty from the 

 adjoining counties were used. Though most of the latter possessed records 

 extending over a period of thirty years, usually for the period 1861-90, 

 a number of them were subject to discrepancy owing to the use of in- 

 different instruments and even the occasional removal of a rain-gauge to 



