18 



MAY 6th, 1884. 

 An Address on "Modern Studies on Climatology" was 

 delivered by J. K. Laughton, Esq., M.A., K.N., President of 

 the Association. 



Of all the Meteorological elements which combine to make up 

 what we call the climate of any country, by far the most important 

 and most generally interesting, is temperature. It is not only that 

 other climatic conditions — such as rain or moisture — largely depend 

 on temperature, but that the degree of heat or cold is in itself, to 

 a f reat extent, the measure of our comfort and discomfort. It is 

 thus that in speaking of climate, we very commonly mean tem- 

 perature only, or temperature aifected by humidity. Now as far 

 as we are concerned, all heat comes from the sun. If there were 

 no STin, we should, practically, have no heat ; we should have a tem- 

 perature (if it may be called so) of something like 500° F. below 

 the freezing point of water. It is difficult, if not impossible, to 

 conceive such a state of things ; but as it would be quite incom- 

 patible with the existence of organized beings, such as we know 

 them, the exact conception of it is unnecessary. 



Since then the sun is the source of all climate heat, it would 

 seem at first sight as if all places on tlie same parallels of latitude 

 oudit to have the same temperature, as if the decrease from the 

 equator towards the poles should be regular and everywhere the 

 same. It is well known to every one that this is not the case ; that 

 the temperatures of different regions in the same latitude often 

 differ enormously ; that, in fact, temperature depends on a great 

 many conditions, of which latitude is indeed one, but sometimes, 

 to all appearance, not a very important one. 



The Lecturer then referred to maps on Avliich were dra-\vn the 

 isotherms, or lines of equal temperature ; calling attention to their 

 irreonlarity, and to their almost total want of agreement witli the 

 parallels of latitude ; and showing, as an instance of this, that, in 

 the winter months, the isotherm of 35° passes through the Hebrides 

 and the North of Scotland, takes a sudden dive to the Southward 

 through the East of France, and then turns to tlie East across 

 the plains of Lombardy; or that the isothenn of 32° runs nearly 



