148 EFFECTS OF HEAT. 



Q. Why do HORSES neigh, CATTLE low, SHEEP 

 bleat, and ASSES bray, at the approach of rain ? 



A. 1st As the air does not contain 

 its full proportion of oxygen, they feel a 

 difficulty in breathing : and 



2ndly As damp relaxes their nerves, 

 they feel languid and uneasy. 



Q- Why do CANDLES and FIKES burn with a 

 BLUER FLAME in WET weather? 



A. As the air contains less oxygen in 

 wet weather, the heat of fire is less intense: 

 and the flame is blue, because the fuel is 

 not thoroughly consumed. 



Q. Why do HILLS, <&c. appear LARGER in 

 WET weather ? 



A. Because (when the air is laden 

 with vapourj the rays of light are more 

 dispersed, and produce a larger reflection ; 

 objects, therefore, seen at a distance, 

 appear larger. 



Q. Why do TREES, &c. in WET weather appear 

 FURTHER OFF than they really are ? 



A. Because the fog or mist diminishes 

 the light reflected from the object ; and 

 as the object becomes more dim, it seems 

 to be further off. 



