14 G Effects of LigJd on Vegetation 



XVIII. Olscndions on the Effects of Light on Vegetation. Bg 



non. JAMES WARREN, esq. f. a. a. 



Milton, January 25th; 1786. 



Ge^'tlemex, 



fflllE investigation of the economy of plants is a sub- 



J 



I ject of universal importance to mankind ; and has 

 accordingly engaged the attention of the philosopher, as well 

 as the husbandman. But; from the intricacy that attends 

 it, it has hitherto disappointed the researches of the first, 

 and the observations of the last, at least in the most useful 

 and material questions ; among which I think are, "What 

 is the food of plants? In what manner is it received into 

 their vessels? And how it operates, to produce such bene- 

 fits to man and other animals? These are yet subjects of 

 discussion and dispute; and are advanced no farther than 

 the conjectm-es of those, who hold different acntiments on 

 different systems which they have adopted \ each of which 

 is far from establishing that decision, which can lead the 

 practical fixrmer to a certain and successful process in culti- 

 vation. We know, in many instance?, that light has a great 

 influence on the growth of plants; and perhaps, they can- 

 not subsist without it. But this is a general provision of 

 nature ; and can receive but little addition from the indus- 

 try of the husbandman. It seems to be rather a sine qua non, 

 than a discovery of the desiderata we wish for. However, it 

 IS difficult, if not impossible, to conclude, that an instance 

 of the effect of Hght on vegetation may not, in some cases, 



lead 



