140 



PROSERPINA. 



empty, unless described as full. But what liquid fills 

 the vascules of the wood, they do not tell 

 us.* I assume that they absorb water, as 

 long as the tree lives. 



20. Wood, whether vascular or fibrous, is 

 however formed, in outlaid plants, first out- 

 side of the pith, and then, in shoots of the 

 second year, outside of the wood of the first, 

 and in the third year, outside of the wood of 

 the second ; so that supposing the quantity of 

 wood sent down from the growing shoot 

 distributed on a flat plane, the structure in 

 the third year would be as in Figure 27. 

 But since the new wood is distributed all 

 round the stem, (in successive cords or 

 threads, if not at once), the increase of sub- 

 stance after a year or two would be untraceable, unless more 

 shoots than one were formed at the extremity of the 

 branch. Of actual bud and branch structure, I gave intro- 

 ductory account long since in the fifth volume of * Modern 

 Painters.' f to which I would now refer the reader ; but 



* " At first the vessels are pervious and full of fluid, but by degrees 

 thickening layers are deposited, which contract their canal." BAL- 

 FOUR. 



f I cannot better this earlier statement, which in beginning ' Proser- 

 pina,' I intended to form a part of that work ; but, as readers already 

 in possession of it in the original form, ought not to be burdened with 

 its repetition, I shall repnblish those chapters as a supplement, which. 

 T trust may be soon issued. 



FIG. 27. 



