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been impregnated with the pyrolignite of iron; 
the flexibility of the wood preserved with these 
alkaline and earthy salts was farther as great as 
at the beginning of the experiment. 
“ Having now come to a conclusion in regard 
to the substances most effectual in preserving 
wood, the next business was to make them 
penetrate its tissue most intimately. Macera- 
tion, M. Boucherie soon found, like his prede- 
cessors in the same path, to be insufficient, the 
substances in solution only penetrating a very 
little way. Tle then tried various processes of 
injection; but all inferior to that imagined by 
M. Breant, and therefore less effectual. He then 
bethought him of effecting the needful penetra- 
tion of the wood in the green state, and before 
it had been sensibly altered by drying and sea- 
soning ; he asked himself if the force which de- 
termines the ascent of the sap might not be taken 
advantage of after the tree was cut down, asa 
means of determining the entrance of a solution 
of pyrolignite of iron? And all his trials in this 
direction answered his expectations fully. M. 
Boucherie had, in fact, discovered a means of 
securing the penetration of the minutest pores 
of the largest log by a substance capable of ren- 
dering it incorruptible. No one before M. Bou- 
cherie thought of taking advantage of an ad- 
mitted physiological fact for such a purpose. He 
announces the principle upon which he proceeds 
in these terms: ‘If a tall tree be cut down at 
the proper season, and the bottom of the trunk 
be then immersed in a saline solution, weak or 
strong, the liquid is powerfully drawn up into 
the tree, penetrates its most intimate tissues, 
rises to its smallest branches and even to its 
terminal leaves.’ In the month of September, 
a poplar, upwards of 90 feet high and nearly 16 
inches in diameter, was cut, and the bottom of 
its bole plunged in a vessel, containing a solu- 
tion of pyrolignite of iron marking 8° of the 
areometer of Beaumé ; in the course of six days, 
it had absorbed upwards of 66 gallons of the 
fluid. In his first experiments, M. Boucherie 
procured the needful absorption by placing the 
bottoms of his trees in vessels containing the 
solution; but this mode of proceeding was ob- 
viously full of difficulties and open to many ob- 
jections. The weight of a green tree of large 
size, with the whole of its top and branches is 
often enormous, and to raise a mass of the kind 
once down again into the perpendicular was no 
easy task; it implied recurrence to certain me- 
chanical means which are not always at hand, 
and necessarily expensive. M. Boucherie, there- 
fore, tried other modes of making the trees ab- 
sorb; he adapted a sac of impermeable material 
to the bottom of the trunk laid on the ground, 
and into this sac he poured his solution, and this 
method answered very well. He next took ad- 
vantage of one or more of the roots to effect the 
imbibition. He next bored a hole into the bot- 
tom of the trunk, still erect; and having brought 
TIMBER. 
the cavity thus made to communicate with a re- 
servoir, he still succeeded. This last pian was 
still farther simplified in proceeding as follows: 
the trunk of the tree is pierced by an auger 
through nearly the whole diameter. Into the 
auger-hole thus made, a narrow saw is passed, 
by working which on either side, the trunk is 
divided internally to a very considerable extent, 
and the majority of its sap vessels are thus cut 
across and made accessible. An impervious cloth 
is then tied round the trunk, below the opening, 
and this is made to communicate with the reser- 
voir of liquid —M. Boucherie was almost neces- 
sarily led, in the course of his experiments, to 
inquire whether the absorbing power of trees 
differed at different seasons or not. He ascer- 
tained by trials made in the months of Decem- 
ber and February, that though in the oak, the 
hornbeam, and the plane, the solution of pyro- 
lignite of iron always rises several feet and even 
several yards, yet that in the colder season of 
the year, it never rises so high as it does in 
summer, in spring, and especially in autumn, 
the season in which the power of ascent is most 
remarkable. This conclusion is obviously of in- 
terest physiologically. It proves that if winter 
be a season of repose for the sap, it is not so 
absolutely. There is one remarkable exception 
to the general fact now announced, and. this 
occurs among the resinous trees that keep their 
leaves till the spring. It has been ascertained, 
by direct experiment, that the ascent of the sap 
continues through the whole course of the win- 
ter in the cone-bearing trees, and this to such 
an extent, that it is always possible to impreg- 
nate every part of their trunk by the way of 
simple absorption at any period of the year. As 
M. Boucherie remarks, this fact might even have 
been foreseen from the fresh and green state of 
the leaves of these trees.—It now became impor- 
tant, in connexion with the practical application 
of M. Boucherie’s views, to ascertain whether or 
not the penetration was energetic in the ratio of 
the vigour of the tree itself, in proportion as it 
was more numerously provided with branches, 
more thickly covered with leaves. Experiment 
showed that the penetration still takes place 
after the removal of the greater number of 
branches, provided only the leading bough or 
terminal crown be left. A stem furnished with 
a number of leafy branches continues, as has 
been said, to imbibe, though separated from the 
roots; but for how long a time will it continue 
to do so? This was a capital point to determine. 
At the end of September, the bottom of a pine 
tree about 14 inches in diameter was first 
put into the solution 48 hours after it had been 
felled ; nevertheless the imbibition was complete. - 
In June, the same success attended the experi- 
ment made on a plane that had been cut for 
thirty-six hours. Still it is certain that the 
penetration takes place with so much the more 
energy as it is arranged close upon the time of 
