ON THE RAINFALL OP THE BRITISH ISLES. 



203 



by paying clerks' salaries out of my own pocket, it will be some years before 

 the inquiry can be completed. Under these circumstances, it seemed un- 

 reasonable to persist in my refusal of an interim investigation, and I have 

 therefore drawn up the following statement. 



My object has been to determine (1) whether the decreased annual fall of 

 rain which has been observed at Greenwich is a local variation, or whether 

 it prevails generally throughout the country ; (2) (having ascertained that 

 the present, temporary investigation shows it to be general) to ascertain in 

 what districts the decrease is most marked. 



Unfortunately there are very few continuous records extending back 

 more than about thirty years. A few, however, are available and, having 

 carefully interpolated for one or two missing years, I have been able to form 

 the following Table from the mean of ten widely separated stations — one in 

 each of the following counties : Devon, Kent, Middlesex, Surrey, Essex, 

 Lincoln, Lancashire, York, Edinburgh, and Argyll. 



It may be well to add that on carrying the examination back to 1800, the 

 fall seems to have been less than it was about 1815, when the following more 

 reliable Table commences. 



Several curious results may be noticed in this Table : for instance, in the 

 first ten years, seven were above the average of fifty years ; in the next ten, 

 six ; in the next, five ; in the next, four ; in the last, three. Again, out of the 

 first twenty-five years, sixteen were above the average ; and in the next, six- 

 teen were below it. 



Means from the above values. 



Mean of 25 years, 



)» » 

 „ 50 „ 



1815-1839 = 28-80. 

 1810-1864 = 27-60. 

 1815-1864 = 28-20. 



