198 Miscellanies. 



vailing opinion, the writer of that article believes that timber is most du- 

 rable when obtained from trees cut during summer. I am not prepared 

 to call in question the correctness of his belief ; but on the contrary, I 

 am able to say, that as far as my observations have been extended, they 

 have proved corroborative of it. There are some points, however, af- 

 fecting his theory, which, I think, require further consideration. 



Agreeably to his view, the sap of vegetables is confined to the al- 

 burnum during summer, but on the approach of frost, it retreats to the 

 heai*t-wood, where it remains during winter. And thus, he supposes, 

 the fluids of the tree continue to circulate between the heart-wood and 

 alburnum year after year while the tree lives. As the writer speaks 

 of the " exact thickness of the alburnum," I presume he means by the 

 term alburnum, all the white-wood, or all those concentric layers which 

 lie exterior to the colored central portion of the trunk ; and from which 

 they are separated by a well defined circle. If this presumption be- 

 true, it appears to me that grave objections rest against his theory. 

 The summer and winter reservoirs, which he appropriates to the sap, 

 are not always of equal capacity ; indeed, they are very rarely, if ever, 

 precisely so. Some trees between one and two feet in diameter, have, 

 as I find by calculation, thirty eight times more alburnum than colored 

 wood. Others, of smaller dimensions, on a ti-ansverse section of the 

 trunk, show a mere speck of heart-wood, capable of holding not more 

 than a two hundredth part of the fluids of the alburnum. If a deduc- 

 tion be made from the capacity of the central wood, on account of su- 

 perior density of structure, the difference will be still greater in the 

 contents of the two reservoirs. The author of this theory, (perhaps I 

 ought to say hypothesis,) must then either find an autumnal outlet for 

 the excess of moisture, or abandon his opinion. 



Again, phytologists tell us, without reserve, that heart-wood consists 

 of " dead and fully formed central layers." If all vital action has 

 ceased in this portion of the tree, it is not only unnatural to suppose 

 that living fluids are deposited for preservation in a dead receptacle, 

 but it is difficult to conceive how these fluids are to be conveyed through 

 lifeless channels. 



In his ninth paragraph, I was struck with the following extraordinary 

 assertion : " The results of these experiments accord with a known 

 fact in regard to the sugar maple, namely, that no sap can be obtained 

 from the tubes of the alburnum of that tree, and therefore they are 

 obliged to bore the hole for the tube through the alburnum, into the 

 heart-wood before it will run." The truth is, that if the bark be re- 

 moved from any part of the sugar tree, the shghtest laceration of the 

 alburnal vessels will produce, at the season of the year alluded to, a 

 copious flow of " water." By means of a penknife, I have often cut 



