108 PRESERVATION OF TIMBER. 



the wood, which they are to preserve, is not kept constantly wet. 

 Solutions of common salt, of chloride of lime, the mother-water ol 

 salt-marshes, &c., were all tried and found useful : casks, the wood 

 of which had been prepared with the chlorides, after having been 

 long kept in very damp cellars, came out as fresh as those which 

 had been impregnated with the pyrolignite of iron ; the flexibility of 

 the wood preserved with these alkaline and earthy salts was further 

 as CTreat as at the beginning of the experiment. 



Having now come to a conchision in regard to the substances 

 most effectual in preserving wood, the next business was to make 

 them penetrate its tissue most intimately. Maceration, M. Bouche- 

 rie soon found, like his predecessors in the same path, to be insuf- 

 ficient, the substances in solution only penetrating a very little way. 

 He then tried various processes of injection ; but all inferior to that 

 imagined by M. Breant^ and therefore less effectual. He then be- 

 thought him of effecting the needful penetration of the wood in the 

 green state, and before it had been sensibly altered by drying and 

 seasoning ; he asked himself if the force which determines the 

 ascent of the sap might not be taken advantage of after the tree was 

 cut down, as a means of determining the entrance of a solution of 

 pyrolignite of iron 1 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 rendering it incorruptible. No one before 

 M. Boucherie thought of taking advantage of an admitted physiolo- 

 gical 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 small- 

 est 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 solution of pyrolignite of iron mark- 

 ing 8° of the areoQfieter of Beaume ; 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 obviously full of dif- 

 ficulties and open to many objections : 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 perpen- 

 dicular was no easy task ; it implied recurrence to certain mechani- 

 cal means which are not always £t hand, and necessarily expensive. 

 M. Boucherie, therefore, tried ether modes of making the trees 

 absorb ; he adapted a sac of imp.jrmeable material to the bottom of 

 the trunk laid on the ground, and into this sac he poured his solution, 

 «.nd this method answered very well. He next took advantage of 



♦Ami. de Chuuic, U !x.\iv. y. 132< 



