146 SYLVA BOOK i 



the more sublime branches, more impregnated with 

 this astral vertue, as not so near the root, which 

 seems to attract rather a cruder, and more common 

 water, through fewer strainers, and neither so pure, 

 and aerial as in those refined percolations, the nature 

 of the places where these trees delight to grow (for 

 the most part lofty, dry, and barren) consider'd. But 

 I refer these disquisitions to the learned ; especially, 

 as mention'd by that incomparable philosopher, and 

 my most noble friend, the Honourable Mr. Boyle, in 

 his second part of the Usefulness of Natural Philosophy r , 

 Sect. i. Essay 3^. where he speaks of the manna del 

 corpo, or trunk-manna, as well as of that liquor from 

 the bough ; also of the sura which the coco-trees 

 afford ; and that Polonian secret of the liquor of the 

 walnut-tree root ; with an encouragement of more 

 frequent experiments to educe saccharine substances 

 upon these occasions : But the book being publish'd 

 so long since this Discourse was first printed, I take 

 only here the liberty to refer the reader to one of the 

 best entertainments in the world. 



But now before we expatiate farther concerning 

 saps; it is by some controverted, whether this exhaust- 

 ion would not be an extreme detriment to the growth, 

 substance, and other parts of trees : As to the growth 

 and bulk, if what I have observ'd of a birch, which 

 has for very many years been perforated at the usual 

 season, (besides the scars made in the bark) it still 

 thrives, and is grown to a prodigious substance, the 

 species consider'd. What it would effect in other 

 trees (the vine excepted unseasonably launc'd) I know 

 not : But this calls to mind, a tryal of Esq ; Brother- 

 ton, (mentioning some excortications and incisions, 

 by what he observ'd in pruning,) that most (if not 



