314 PHILOSOPHICAL TRANSACTIONS. [anNO I676. 



trees^and other plants grow in height and thickness ; of which ^^ I doubt not but 

 Dr. Grew has written so learnedly that I shall not need to notice it here. 



In fig. 8;, pi. 9, AB is one of the great pores or vessels of an ash twig of 

 one year's growth, cut lengthwise through the middle of the pores, which ves- 

 sels consist of tranparent globules/^ wherein might be plainly seen the small 

 oblique membranes called valves/* which membranes do not lie with their 

 upper part extended one and the same way, but so as that two sides of them, 

 with their upper end, reach towards one another, as CC and DD. And if we 

 suppose that the hollowness of these greater vessels is as large as a hair, we 

 may then very well say, that the hollowness of the small ones^^ is at least 25 

 times smaller than such a hair. That these vessels consist of globules, ^^ I have 

 not only seen in ash- wood, but also in walnut, hasel, apple, pear, and plum, 

 &c. trees. 



In fig. 9, AB exhibits some of the small vessels that make up the firm 

 wood,^'' cut off close to the bark lengthwise. Of these vessels ^^ there lie 8, 

 3 0, or 12 together, as at C and D, in the manner of a weaver's shuttle, lying 

 in some places irregularly, the one close by the other, and in other places 

 somewhat more dispersed. 



In fig. 10, ABCD is the bark^^ of the twig, which is only represented with 

 bare lines, because that now the plant is growing, by which the bark is changed 

 from what it is in winter. AHHDEGF is the eighth part of the wood of 

 an ash twig one year old, cut transversely, not made up wholly of firm or close 

 parts, but partly too of large vessels,^" which yet differ much among themselves 

 in size, and which are seldom or never perfectly round, standing also near the 



English tongue to have recourse to the explications) to conceive there were no other represented at 

 all. And for fig. 18, that being but one, which the author thought sufficient for example's sake, 

 amongst so many more figures, Mr. Leewenhoeck it seems overlooked it ; see the latter end of the 

 note 4. — '^ The causes of which are assigned and explained in Dr. Grew's Anatomy of Trunks, part 

 2, ch, 5. And of a great many more particulars throughout the whole economy of vegetation in all 

 the aforesaid three books — '^ See the note 8. — '* See the note 9- — '* Of the size of these valves j see 

 Dr, Grew's computation. Anatomy of Trunks, p, 18, 19.—'^ See the note 8. — " Dr. Grew's de- 

 scription of this 5 see Anatomy of Trunks, p. 22 to 26. — '^ See the note 5. — ^^ See Dr. Grew's de- 

 scription and representation of the bark in his Anatomy of Trunks. And of tliis very bark, fig, 15, 

 with tlie explication. And it is fiirther to be noted, that the same author in his Anatomy of Trunks, 

 informs us that there are two sorts of vessels visibly distinct in tlie bark of most, if not of all, sorts of 

 trees, and other plants, as well as in the wood. Wherein Signor Malpighi also agrees with him, at 

 least that they are to be found in many trees of two distinct species; see his Idea, p. 2, towards the 

 end. And Dr. Grew also both observes and shows three distinct species of vessels, even in the bark 

 of some plants; see Anatomy of Trunks, p. 14 to 17, and fig. 19, 20, 21. — ^ Which Dr, Grew 

 •alls the air-vessels, (Malpighi Fistulas spirales) and describes. Anatomy of Roots and Trunks, p. 26 



