A year's weather. 393 



April 261-ins 2-48-ins 1-36-ins. 



May 2'45-ins 2-26-ms 1-55-ms. 



June 2-.S9-ins 2'86-ius 1-83-ins. 



July 2-50-ins 1'62-ms l-76-in3. 



Total ... 21-19-ins 16-74-ms 14-27-ins. 



A glance shews how it is that we are enjoying the distinction 

 this year of being one of the most favoured counties as regards 

 weather. I receive many letters from correspondents asking if 

 Cornwall is under sunshine and suitable to visit, and this year my 

 replies have invariably been "Weather glorious ! " A rainfall for 

 the seven months seven inches below the mean rainfall, and only 

 two-thirds the usual downpour, must give dryness. 



This dryness has been favourable to the potato and to the corn, 

 as these crops have not felt so much the ill-effects of moulds, smuts, 

 and rusts as they do in warm, wet weather. How little is popularly 

 known about these enemies, and yet how interesting their history 

 to the scientific mind. When one thinks that the smallest wrinkle 

 in a potato leaf holding a drop of rain or dew is a lake, comparatively, 

 for the development of any potato-disease spores which may fall 

 into it, one feels glad to record a July free from mugginess, i.e., 

 warm, steamy wetness. A potato-disease spore falling into such 

 a drop of warm rain, small though the spore be, breaks up into a 

 score or two of minute swimming spores, each bent on boring, by 

 means of little rootlets, into the potato leaf, and stealing the starch 

 ready in the leaf to be passed into the tuber. Once in possession, 

 leaf, stem and tuber fall before their poisonous attack. 



Generally the barometer stood high during the greater part of 

 the month, yet it had a range of over eight-tenths of an inch. 



The highest heat in shade was on the 30th, temperature 80 

 degrees; the lowest 42 degrees, on the night of the 23rd; a range 

 of 38 degrees. 



The wind had about as many records from the north and 

 east, as from the south and west, the latter bringing us the rain 

 mentioned. 



From correspondents I find that my observation about the 

 appearance of the Clouded Yellow butterfly Colzas edusa, Fabr. , in the 

 last month's weather letter is confirmed. Records of its occurrence 

 in addition to my own at Truro and The Lizard, are to hand 

 from Perran, Lostwithiel, Par, Worcester, and Essex. 



