358 FROST. 



A. These cracks in the earth let in 

 the air, the dew and rain, and many 

 gases favourable to vegetation. 



Q. Why does the EARTH CRUMBLE in SPRING ? 



A. In spring the ice of the clods 

 dissolves, and the particles of earth 

 (which had been held apart by the 

 expanded ice) are left unsupported, and 

 tumble into minute parts (because their 

 cement is dissolved. 



Q. Why does MORTAR CRUMBLE away in 

 FROST ? 



A. If the mortar was not dried in 

 the warm weather, its moisture freezes, 

 expands, and thrusts the particles of the 

 mortar away from each other; but (as 

 soon as the frost goes) the water con- 

 denses and leaves the mortar full of 

 cracks and chinks. 



Q. Why does STUCCO PEEL from a WALL in 

 FROSTY weather ? 



A. If the stucco was not dried in 

 the warm weather, its moisture freezes, 

 expands, and thrusts its particles away 

 from the wall ; but as soon as the water 

 condenses again by the thaw, the stucco 



