THE CLIMATE OF WEST CORNWALL. 43 



My purpose will be best served by taking the subject under 

 three beads, viz., temperature, rainfall, and sunshine. 



Temperature. A climatic condition which is generally 

 agreeable to the healthy, and which becomes a real necessity to 

 the weak is equability of temperature. What is desired is that 

 there shall be no violent transition from heat to cold, or vice 

 versa, from month to month and from day to day, but that such 

 changes as Nature imposes in this respect shall be so graduated 

 as to cause no serious inconvenience from a sanitary or hygienic 

 point of view. More particularly is it desired that the diurnal 

 range or differences in day and night temperature shall not be 

 extreme. 



These conditions are characteristic of the climate of 

 Cornwall in a marked degree ; this should be made widely 

 known, not only for the more exact information of residents in 

 the County, but also for the benefit of those to whom an equable 

 climate is essential to the maintenance of good health, if not an 

 absolute necessity to existence, particularly during the winter 

 months. 



The mean annual temperature of West Cornwall, as deduced 

 from observations made at Truro, Falmouth, and Helston, 

 between the years 1871 and 1887 is 51°, and the daily range of 

 temperature 11°. These observations show that there is not 

 much more than 1 ° difference in the annual temperature at these 

 respective stations, whilst the daily range differs by 5°, Falmouth 

 showing the least range, 8^°, owing to its closer proximity to 

 the sea. 



The information conveyed by the diagrams accompanying 

 this paper has been deduced from the observations made at 

 Falmouth only, and for the following reasons. (1) That I have 

 at my command all the records taken at the Falmouth Observatory 

 from its establishment to the present time, extending over 24 

 years. (2) That those records have been made with perfectly 

 reliable instruments, frequently verified, and well placed, and 

 under similar conditions throughout the whole period, and are 

 therefore highly trustworthy. The results here shown for 

 Falmouth may also be regarded as fairly representative of the 

 climate of other seaside stations as Penzance, Marazion, and 



