332 THE FLOEIST AND 



the interior of freshly cut wood, -which preserves them indefinitely from 

 decay ; but it must be observed that all woods do not permit penetration 

 equally. The beech, elm, and fir, readily admit all kinds of salts into their 

 tissue' The oak impregnates completely its sap-wood, while the heart of 

 the tree absorbs absolutely nothing. This last fact is not wanting in impor- 

 tance, in view of the value of forest products, for we see at once that the 

 part of this tree-'which was thrown aside, or cut away as unfit for any use, 

 acquires immediately, and merely by the fact of its impregnation, at least 

 as much value as the heart of the tree, and that it can te employed with at 

 least as much advantage as this latter part. 



. Different salts have been tried in order to find which of them possessed in 

 the highest degree the faculty of preserving wood, and the sulphate of cop- 

 per has been acknowledged the only one which could be employed with entire 

 success. 



M. Decaisne presented, to the company a large piece of beech plank, 

 divided in half, and in its length into three parts, by means of two cuts of a 

 saw, of which one was impregnated with sulphate of copper, another with 

 corrosive sublimate or chloride of mercury, while the middle part repre- 

 senting the heart,' had not undergone any impregnation. This plank buried 

 in the earth during five years, leaving one of the extremities above, Jhas 

 consequently been exposed to all sorts of atmospheric variations. At the 

 end of this time, the central part was found completely altered ; that sub- 

 mitted to the action of the mercury, was partly destroyed, while that 

 injected with sulphate of copper, was preserved as sound as if it were 

 just cut. 



The same trials and the same results appear on other pieces of different 

 woods. A lath of elm impregnated with sulphate of copper which, for the 

 last seven years, has served at the Museum, to form with others a trellis, 

 appeared yet as solid as if it had just come from the wood-yard. 



The process of the injection of wood with the salts of copper, is as simple 

 as easy. For thin wood intended for rods, it consists in plunging the base 

 of a branch furnished with leaves, into a tub containing the solution. The 

 liquid ascends into the branches by the action of the leaves, and the wood 

 is impregnated with the preservative salt. As for logs, the operation con- 

 sists in cutting down the tree to be operated upon, to fix at its base, a 

 plank which is fixed by means of a screw, placed in the centre, and which 

 can be tightened at will, when placed in the centre of the tree ; this plank 

 has on the side to be applied to the bottom of the tree, a rather thick shield 

 of leather, cloth, paste-board, or some other substance intended to establish 



