212 The seven VEGETABLE FAMILIES. 
this forces itfelf out in numcroits and vafl Leaves, whofe Bafes, in a man- 
ner, form that Stem which tliey feem only to cover. And finally, in the 
c('mmon courfe of Plants the Flefli, as is moft natural, has the predomi- 
nance ; and carries up the afeending Sta'k, a firm, dilVinvft, and vigorous 
luppoit to the Friidlitications. 
C El A P. XLIX. 
Of the Effect of L i g ii t on Plants. 
TJ A V I N G fecn, in a variety of indances, what AAgetation is, and 
^ what the Boaies are which are producetl by it, w-e might here clofe 
the prefent Enquiry : but there remains a point of great impcrtance yet to 
be difeufT d j tho’ it be one not generally conceived as relating to the fub- 
jeiTt. What Heat and Moisture can effedl, we have fecn j but there 
is a third Agent, Light, cf equal clFicacy ; tho’, in the midll of its own 
hri datnefs, hitherto obfeure. 
That fingular property w'hich is called the Sleep of Plants, and which 
had been admired, tho’ not underdood, led me to thofe Enquiries, in w'hich 
I found Light to be the Caufe; and thofe have led to others, new all of 
them, and all wonderful j from tlie refult of w’hich I may be bold to 
affirm, that Vegetables owe their Bulk and Quantity indeed, to the Earth, 
foftened by Water, and aiftuatcd by Pleat; but their Forms, their Colours, 
and, in a great meafure, their Q^lities, to this hitherto unconfidercd Agent, 
Light. 
A SEED committed to the Earth will grow, tho’ it be covered up in 
perfect Darknefs, but the Growth will be weak, and the Body itfelf, in 
t!ie highed degree, deformed : a Seed of the fame Plant, covered as clofe- 
Iv, but with a tranfparent body, wd!l grow as free, and b; as w'ell pro- 
portioned, as in the open air. Thus, if two Peafe be Town in the lame 
Border, and the fpot w’here one dands he covered u'lth a Box of Wood, 
and that w'here the other is placed, witli a Bell-glafs of equal bignefj. 
The Plant under the Box will be dender, yellow, infipid, and almod leaf- 
ids ; that under the Glafs will have its natural Proportions, and proper 
Colour: the Leaves will grow regular, tlie Tade will be legunimous, and 
the whole Plant well formed, and green. 
In our common Gardens, tiie Anemone is poor In Colour when it is 
under the fhadow of Bufhes ; and I lad year obferved at Sion-Houfe, that 
even 
9 
