1882.] on Climate in Town and Country. 19 



sun. (2) Land and water — ocean and atmospheric currents. (3) Aspect 

 — slope of ground, exposure or slielter. (4) Nature of surface. 

 (5) Eeflection from land and water. (6) Eain and clouds — suspended 

 matter in the air. (7) Latitude — incidence of solar rays, thickness of 

 air. (8) Presence or absence of aqueous vapour. Of these, the first 

 three are obvious and require no comment. The remainder are less 

 well known, but their importance demands our special attention. 



Climate, or rather genial climate, is ultimately resolvable into two 

 prime factors — sun-warmth and air-warmth. The amount of sun- 

 warmth (assuming the sun's heat to be constant) depends upon two 

 things only — length of day, and quantity of suspended matter and 

 aqueous vapour in the air. The warmth of the air depends upon 

 contact with matter heated by the sun's rays and upon the stoppage 

 of radiation from the earth by aqueous vapour. This heated matter 

 is : — (1) Sea or land. (2) Suspended matter in the air — cloud, dust, 

 smoke. (3) Aqueous vapour. 



These two factors were first considered in their relation to 



Country Climate. 



The feeling of warmth and comfort in the open air is produced 

 either by direct solar radiation, even if the air be very cold ; or by 

 the warmth of the air itself. Upon both of these, the nature of the 

 surface upon which the sunlight falls has a paramount influence, as is 

 seen from the results of experiments on sun temperature recorded in 



the following table : — 



Influence of Surface. 



Norvxvj. Q 



Green grass 57 * 3 C. 



Parched grass Gl'2 



Bare soil 60*6 



Newly-mown grass 56 * 5 



"White paper 73-5 



Hesse Cassel. o 



Black caoutchouc 54 • 7 C. 



Black silk 56-5 



Plane glass mirror 64 • 



Slightly concave metallic mirror 64-0 



Green grass 58 '5 



White paper 67 ' 7 



Sioitzerland. Mortaratsch Glacier. 



o 



Black caoutchouc 39 • C. 



Bare white ice 47 * 5 



White paper 53 • 



Summit of Gornergrat. ^ 



Dazzling white snow 59'0 C. 



• White paper 61*2 



Pontresina. ^ 



Whitepaper 66-2 C. 



Grass 54-0 



Grey rock 54-0 



Black caoutchouc 5G • 4 



C 2 



