President's Address. 



215 



in Britain. A small portion of this is exported, but the 

 great bulk is used for domestic purposes and manufactures, 

 —for animating the giant arm of the steam-engine, and for 

 sending our steam-ships over every region of the globe. 

 The present aspect of the county was next alluded to, — its 

 division into three alluvial valleys, watered by three rivers 

 which flow into the estuary of the Firth, — the Pentland 

 range of hills, their diversified scenery, — and the remarkable 

 basaltic rocks surrounding and forming the basis on which 

 the city is built. There are no means of knowing what was 

 the condition of the local atmosphere of Mid-Lothian in 

 former times — at periods when the country was more densely 

 covered with wood, when the ancient forests of Scotland 

 still remained, when the surface of the soil was only par- 

 tially cleared and cultivated, and imperfectly drained, and 

 when marshes and lochs were greatly more abundant than 

 they are at present. In the absence of actual facts, people 

 are apt to draw on their imaginations and feelings ; and 

 it depends a good deal on the individual temperament 

 whether we hear that the seasons are become much more 

 severe and un genial, or warmer and drier, than they were in 

 bygone days. It was only towards the end of last century 

 that scientific instruments were employed to indicate the 

 climate of the country. From those begun by Professor 

 Playfair in 1771, and others, continued down to the present 

 day, it appears pretty evident that no change of climate has 

 taken place during the last ninety years. Considerable 

 varieties of seasons occur ; the general or normal was pointed 

 out, and the occasional or abnormal, with their distinctive 

 peculiarities, and the great leading or general causes of dif- 

 ference, traced to the predominating power of the south- 

 west and north-east air currents, — the predominance of one 

 or the other forming the main cause of the varieties of sea- 

 sons, — and to the influence of the great Gulf Stream, which 

 flows past the British Isles. Local ameliorations of climate 

 by drainage, cultivation of the soil, protection of plantings, 

 &c, while they are of the greatest importance to the agri- 

 culturist and in a sanitary point of view, would appear to 

 be too small to affect the general climatal averages. The 



