BULLETIN OF THE BUSSEY INSTITUTION. 45 
The amount of nitrogen contained in the percolated wood has been 
given already on page 32. 
As for wood that has been leached with dilute acids, instead of water, 
it would appear that, although a considerably larger amount of the ash 
ingredients are dissolved by the acids than by water alone, it is still, 
practically speaking, impossible to remove the whole of the ashes in this 
way. Bischof,* for example, on attempting, for purposes of analysis, to 
extract the alkalies completely from various kinds of woods by long con- 
tinued boiling with sulphuric acid, was unable to accomplish the wished- 
for result. The ashes obtained from woods that had been thoroughly 
leached in this way, still contained some salts of the alkalies. Sacc,t by 
using muriatic acid, succeeded in removing a very large proportion of the 
ash ingredients from wood of the silver-fir. Thus, in the original fir- 
wood sawdust dried at 100°, he obtained 0.550 of ashes. But on digest- 
ing such sawdust with muriatic acid of commerce, mixed with half its 
weight of water, and afterwards washing with water, and drying the resi- 
due at 100°, he got only 0.07% of ashes. It is to be expected, of course, 
that the acids, particularly muriatic and nitric, would remove a larger 
proportion of the phosphates from wood than mere water, and that they 
would dissolve out some of the lime compounds also that are left in the 
form of carbonate of lime when wood is burnt; and that this is actually 
the case may be seen from the experiments of Dussance,{ who exhausted 
red sandal-wood (Pterocarpus santalinus) with water, with alcohol, and 
with muriatic acid used in succession. In the ash of the matters dis- 
solved by water from the wood, there was found a quantity of carbonate, 
sulphate, and chloride of potassium and sodium, as well as silica, oxide 
of iron, and sulphate of lime; the acid, on the other hand, dissolved an 
abundance of oxalate and phosphate of lime, and some phosphate of mag- 
nesia. The wood that had been leached, as above stated, gave 1.840 
of ashes, consisting of silica and carbonate of lime. The acid used in 
these experiments marked 15° B.; a quantity of it was left to stand in 
the cold upon the wood during 24 hours, and was then renewed until 
the fresh portion ceased to dissolve any thing. From three different sam- 
ples of unleached sandal-wood, Dussance obtained respectively, 2.03, 
2.10, and 4.46 0% of ashes. 
The general conclusion to be drawn from all these experiments is 
clearly, that leached woods or herbs or leaves or bark contain a very 
much smaller proportion of fertilizing substances than the original 
unleached materials; and that practically, no matter whether they be 
fresh or rotten, they have very little real value as manure. This con- 
* “ Journal fiir praktische Chemie,” 1849, 47. 196. 
Tt “ Annales de Chimie et de Physique, 1849, 25, 223. 
{ “ American Journal of Pharmacy,” 1860, 32. 6. 
