142 



ELEMENTS OF GENERAL SCIENCE 



water are placed on the stove and exposed equally to the heat- 

 ing surface, it will be found after a short time that the iron is 

 much hotter than the water. The same amount of heat has 

 much less effect on the water than on the iron, so far as rais- 

 ing its temperature is concerned. The amount of heat which 

 will warm a pound of iron 1 C. will warm a pound of water 

 only 0.11 of 1 C ; that is, it takes 0.11 as much heat to pro- 

 duce a given rise in temperature in iron as is required for the 

 same rise of temperature in the same weight of water. If we 

 had used soil instead of iron, we should have had a result 

 somewhat similar, but there are so many different kinds of 

 soil that differing results would be possible. 



FIG. 76. Cities with different locations in the same latitude 



158. Cooling of land and water. The land cools more 

 rapidly than the water, and this is at least partly due to the 

 facts that have been mentioned in connection with the heat- 

 ing. As it is necessary to put more heat into water than into 

 land in order to raise its temperature a given amount, so the 

 water gives off this larger amount of heat when it cools. 

 Furthermore, as water cools it gives off its heat slowly, and 

 since much of the heat is in the deeper parts of the water, it 

 is not readily given off. 



We may therefore expect that any body of water will be 

 cooler in summer than the neighboring land, at least during 

 the daytime and while the sun is shining, and that breezes 

 from water to land will be common. During the winter the 

 water may remain much warmer tlian the land. 



