POTATOES. PLANTS. 405 



(or blue colour) ; hence the yellow sap 

 of the potato is not converted to green 

 hy carbon. 



Q. Why are potatoes (which grow EXPOSED 

 to the air and light} GREEN ? 



A. Because the sun-light increases 

 their carbon ; which (mingling with the 

 yellow sap) turns the potato green. 



Q. Why is it DANGEROUS to SLEEP in a room 

 which contains LIVING PLANTS ? 



A. Because they exhale carbon in the 

 dark in the form of CARBONIC ACID GAS, 

 which is destructive to animal life. 



Q. Why are SOME things (like glass) TRANS- 

 PARENT ? 



A. In transparent bodies (like glass) 

 all the rays of light emerge on the opposite 

 side. 



Q. Why are SOME things SHINING and 

 splendid ? 



A. Those objects which reflect the 

 most rays are the most splendid; and 

 those which absorb them most, are dull. 



Q. Why are DESERTS so DAZZLING in summer 

 time? 



A. Because each separate grain of 



