DISTRIBUTION OF LEPIDOPTERA. 



31 



at our sea-coast stations (with throe exceptions)." This seems, at first 

 view, paradoxical, but is really not so, if we reflect that each square 

 yard of sea presents one square yard of evaporating surface ; whilst on 

 land, from its porosity and vegetable clothing, each square yard pre- 

 sents many square yards of evaporating surface, and often nearly as 

 moist a one as that of the sea itself. The fourth and fifth items 

 would lead to there being more frequent sunshine and to its being 

 more effective at the coast stations. This, no doubt, will increase the 

 mean annual temperature of these stations, but, except in this result, 

 is not illustrated by Mr. Bayard's figures. As the freedom from cloud 

 is very marked at our south coast stations in winter, as well as in 

 summer, they would no doubt have longer and more frequent spells of 

 sunshine, which, acting on initially warmer conditions, would give, 

 especially in favoured corners, if not a summer temperature, at least 

 one much above our English notions of winter, and this for a few 

 hours or even a few days at a time, 



I do not know that any figures precisely illustrating this point 

 have been digested, and to do so would involve an immense amount 

 of labour. The less striking, but more weighty, figures involved in 

 averages show us on the south and west coasts that, whether we take 

 minimum, mean, or maximum temperatures, the coast stations have an 

 advantage during the winter of from 2deg. — 4deg, F. I have ex- 

 tracted some figures to exemplify this, selecting as nearly comparable 

 inland and coast stations as are afforded, giving in some the mean, in 

 others the maximum and minimum figures : — 



The weekly weather reports of the Meteorological Office give figures 

 described as "day degrees above" (and below) 42deg. for the week 

 for each station. I am not aware that these have been summarised in 

 any way for each station or averages taken, and the labour of doing so 

 would be great, so that I have not undertaken to do it, I have, for the 

 sake of exemplifying the meaning of these figures, so far as they concern 

 my present subject, made a comparison of these for the stations of 

 Douglas and Cheadle, a coast station and an inland one at a little 

 elevation. These figures are those of only one year, and, therefore, 

 must not be taken as necessarily normal figures for either station, but 

 they are nearly as trustworthy for comparison of the two stations as if 

 they were averages of a long period. The coast station is a degree of 



