HG. 
17. $. Firft, What was faid before, is to be remembred, that here 
the Aer is not a folitary, but concurrent Caufe. So that befides the 
ificacy of this, we are to confider that of the feveral parts of the Plant, 
by which the Contexts both Aereal and Liquid are fupplied to the 
Flower. 
18. §. Secondly, Thatin the Lympheduits of a Plant, Sulphur is 
the predominant Principle,and much more abounding than in any other 
part ofa Plant, as alfo hath been formerly fhewed. 
19. $. Thirdly,That it appears,according to what we have obferved 
in the Anatomy of the Flower, That the quantity of Lympheduds with 
relpcét to the Aer-Veffls is greater in the Flower than in the Leaf 
20. $, Itfemeth therefore, that the Aer-Veffels, and therefore the 
Aer, being predominant in the Leaf; Green, is therein alfo the predo- 
dominant Colour. I fay predominant, becaufe there are other Colours 
lye vailed under the Greez, even in the Leafe, as will hereafter appear 
more manifeft. 
21. $. Onthecontrary, the Lympheduéfs, and therefore the Sul- 
plur, being more, and the Aer-Fefels and therefore the Aer, leß, in 
the Flower than in the Leaf; the ambient Aer alone is not able to con- 
trole the Sulphur fo far, but that it generally carrys the greateft port 
in the Produéfion of the Colour. Yet in different degrees; For if 
the proportion betwixt the Lympheduels and the Aer-Veffels be more 
equal, the Flower is cither White or elle Yellow, which latter Colour is 
the next of kin to a Green. If the Sulpkur be fomewhat predominant, 
the Flower will thew it felf Red at firft; but the ambient Aer hath fo 
much power upon it, as gradually to tum the Red into a Blew. But 
if the Sulphur be much predominant, then the Acid-of the ambient Aer 
will heighten it to a fixed Red, 
22. $. Hence it is, that Yellows and Greens are lefSalterable, upon 
the drying of Plants than other Colours; fü. Becaufe the Aer being pre- 
dominant in their Produéfion, they are the lef lyable to faffer from it 
afterwards. Whereas Reds and Purples, in the Production whereof 
Sulpkur is predominant, are very changeable. Sothe Red Flowers of 
Lyfimachia, upon drying, turn Purple, and the young purple Flowers of 
gles turn Blew. Solikewile the Purple of Bilberries, and the Crimfon 
of baked Damafcens, both turn Blew. For being gathered, and fo wan- 
ting a continued fupply of frefh Su/phur, to bear up the Colour againft 
the force of the 4er; it ftrikes it down at laft from Red to Purple or 
Blew. Uconclude therefore, that one Principal Canfe of the Variety of 
Colours in the Flower, is the over proportion of the Lymphedutfs to 
the Aer-Vefféls, and therefore the dominion of the Sulpkur over the 
Aer, therein. 
23. $. - Ifit be objected, that the Aer doth not deepen, but highten 
the Colour of the Blood: I anfwer, Firf?, That I am not now {peaking 
of Animal, but of Vegetable Bodies ; the fame Aer whichhightens the Co- 
Jour of Blood one way, may deepen that ofa Flower,another: nay and 
may highten that of fome Flowers too, fome other way. 
24. § And therefore, Secondly, it is to be confidered, That as 
there is not one only, but divers Saline Prizciples in the Aer; fo are 
there alfo in the feveral Parts of one Plant 5 as in the Root,of one fort 5 
in the Leavs, of another 3 inthe Flower, of another; and fo in the 
other Parts, For fince the Figuration of the Parts of a Plant a 
chicfly 
