SHIP TIMBER. 
51 
X. 
On the Preparation of Forest Trees for immediate Use , and 
: :r easing the Duration of Timber. Communicated by Capt. 
Layman, of the Navy. (From his “ Precursor.”) 
T HE juices of a tree being, like the blood of an animal, 
essential to vitality, but tending to corruption imme- 
diately after dissolution, accounts for the well-known fact, 
that the duration of timber is in proportion to the quantity and 
nature of the juices contained therein at the time of felling 
and when brought to use. It is, therefore, obvious, that by 
withdrawing such juices or blood from a tree while standing, 
the oak (as expressed by the celebrated Roman architect Vi- 
truvius, and by Pliny J “ will acquire a sort of eternity in its 
duration.” But as neither the mode mentioned by those cele- 
brated ancients of cutting a kerf round the bottom of a tree 
while standing, as performed in Bengal, or the one suggested 
by Dr. Plott, of decorticating the tree, leaving it standing, as 
practised by the natives of Malabar for ages, will effect this 
desideratum, I made the following analysis : 
On the 1st of June, 1812, I made experiments upon grow- 
ing young oaks, one of which, that had been operated* upon, 
was converted the next day, increased in strength in the pro- 
portion of 435 to 6op, and when doubly prepared, to 845. 
And, as a test of comparative duration, I made extracts from 
the heart and sap of the same tree in its natural state, and 
when prepared. The following is the result : 
1 . The sap, or embryo wood, in its natural state, speedily 
concreted, and mucor or mould was formed in fourteen days. 
2. The heart, in its natural state, contained much less putres- 
cent matter than the embryo, but a larger portion of gallic 
acid, and acrimonious liquid. This extract had a smell like 
fetid ditch water, and mucor was formed in forty-nine days. 
3. The heart of the prepared oak is perfectly sweet to the 
smell, and has no other appearance but a pellicle from the 
glutinous matter contained in the wood. 
4, The embryo wood of the prepared part has the same ap- 
pearance at the heart, being equally free from any symptoms of 
putrefaction. 
* This oak, from the wetness of the season, contained 6-10ths 
of its weight in fluid: but in general I have found (5-1 lths in June, 
and 4-llths in January, to be the quantity of fluid contained in grow- 
ing oaks. E it 
On the dura- 
bility and me- 
lioration of 
timber for na- 
val construc- 
tion. 
