234 



A DISCOURSE 



BOOK I. not so near the root, which seems to attract rather a cruder and more 

 """y^'^ 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) considered. But 

 I refer these disquisitions to the learned ; especially, as mentioned by 

 that incomparable Philosopher, and my most noble friend, theHonourable 

 IMr. Boyle, in his Second Part of the Usefulness of Natural Philosophy, 

 Essay iv. 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 Cocoa- 

 trees afford ; and that Polonian secret of the liquor of the AValnut-tree 

 root ; with an encouragement of more frequent experiments, to educe 

 saccharine substances upon these occasions : But the book being 

 published 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 bysome 

 controverted, whether this exhaustion would not be an extreme detriment 

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

 bulk, if after what I have observed 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 con- 

 sidered ; what it would effect in other trees, the Vine excepted when 

 unseasonably lanced, I know not. 



4. Whilst the second edition was under my hand, there came to me 

 divers papers upon this subj ect, experimentally made by a worthy friend 

 of mine, a learned and most industrious person, which I had here once 

 resolved to have published, according to the generous liberty granted me 

 for so doing ; but understanding he was still in pursuit of that useful and 

 curious secret, I changed my resolution into an earnest address, that he 

 would comrriunicate it to the world himself, together with those other 

 excellent inquiries and observations, which he is adorning for the benefit 

 of planters, and such as delight themselves in those innocent rusticities. 

 I will only, by way of corollary, hint some particulars for the satisfaction 

 of the curious ; and especially that we may in some sort gratify those 

 •Mr. Olden- camcst suggcstious and queries of the late most obliging publisher* of 

 the Philosophical Transactions, to whose indefatigable pains the learned 



