

THE NURSERY. 295 



and the quality of the plant deteriorated, if there is 

 not the light of the sun along with it. 



The soil, the humidity, the air, the heat, and the 

 light must, like all causes which work jointly in 

 producing an effect, be duly proportioned to each 

 other ; and when, in any combination of that kind, 

 there is any one of the causes over which we have 

 no control, we must regulate our measure of all the 

 others by that. Now the light and heat of the sun 

 are the only causes of the growth of vegetables 

 which are without the control of man as to quantity, 

 and the light is most exclusively so. We have not 

 the smallest power over it, either in respect of du- 

 ration or of intensity. Perhaps something might 

 be done by means of mirrors, but they have not 

 been tried, and they could not be used on the great 

 scale. Indeed, it is probable that any attempts to 

 increase the intensity of light by artificial means 

 would do mischief rather than good. On sunny 

 days, any additional concentration up, even to that 

 which would burn the plants if dry, and boil them if 

 moist, could be obtained ; but then, as there is no 

 calculating when it shall be sunshine and when 

 cloudy, the transition from the artificially increased 

 sunbeams to the natural shadow of clouds would be 

 destructive. Thus the safe plan is to regulate all 

 the other matters by the natural light. 



Here a little fact presents itself, which is not 

 wholly unworthy of notice. The first necessary 

 that man has to find, by skill and artificial means, 

 is food ; and light, the agent in vegetation over 

 which he has the smallest control, appears to have 

 less to do in preparing vegetables for food than in 

 preparing them for any other purpose. Succulent, 

 pulpy, and farinaceous matter, the kinds which are 

 most nutritive, are best when prepared out of the 

 immediate reach of light. When part of a potato is 

 above the surface, the light turns it green, and the 

 taste is unpleasant. Allow it to be formed, and to 



