CHEMICAL RAYS. 43 



in 1851, thirty-three dozens; and in 1850, thirty 

 dozens." 



The rays of the sun possess certain chemical 

 properties which produce saccharine fermentation 

 in the fruit. . Every one who eats it knows how 

 much superior the flavor is of those which have 

 been beautifully colored to others of the same va- 

 riety which are green. In no sort is this difference 

 more strongly marked than in the Vicar of Wink- 

 field's pear. Those which are colored rijDen easily, 

 their flavor is very good, while in the remainder 

 the saccharine fermentation has never commenced, 

 and they are only fit for culinary purposes. When 

 we examine the best system of pruning, we shall see 

 that the most successful cultivators have adopted 

 those plans which give abundant opportunity for 

 the rays of the sun to reach every fruit. 



Not only does the light of the sun influence veg- 

 etable growth, but that of the moon affects them 

 more than might be expected. It is well known 

 that during the day the leaves are constantly de- 

 composing the water contained in their sap, and 

 setting free the oxygen, while they store up the 

 carbon. In the night this function ceases : the 

 oxygen is slowly absorbed, and carbonic acid evolved. 

 Therefore, in the morning the plant must first re- 

 place the carbon which was lost during the night 

 before it can grow. 



According to Professor Zantedeschi, in moonlight 



