A TMO SPHERIC TEMPERA T URE8 



133 



places north of the equator, the length of the day in the 

 northern hemisphere increases and the time that a place is 

 in the sunshine is greater, so that it receives more heat 

 from the sun. On the 21st of. June all points within 

 231 of the north pole, 

 as at North Cape, have 

 24 hours of sunshine, 

 and the amount of heat 

 received at the pole dur- 

 ing these 24 hours is 

 greater than that re- 

 ceived at the equator 

 where the day is only 

 about half as long. 



Although the latitude 

 of a place has much to 

 do with the amount of 

 heat received, there are 

 also many other things 



which affect its temperature. This will appear when we 

 consider that Venice, Italy, with its mild and equable 

 climate is in almost the same latitude as Montreal, Canada. 



As has been seen, the height above the sea makes a 

 difference with the temperature, since- there is less thick- 

 ness of air above and therefore a thinner blanket to hold 

 the heat. Then, too, the kind of soil affects the tempera- 

 ture. If the soil is sandy and there is little or no veg- 

 etation, it becomes rapidly heated in the daytime and 

 radiates back the heat into the air very rapidly, thus 

 making the temperature of the air near the surface v.ery 

 hot during the day ; while at night, when the sun is not 

 adding heat, it rapidly loses the heat acquired during the 

 day, and so the temperature of the air becomes low. In 

 the daytime on great sandy deserts the heat is almost un- 



A WINTER SCENE IN VENICE. 



