A4 BULLETIN OF THE BUSSEY INSTITUTION. 
The increase in the proportion of ashes on leaching the barks and 
heart-wood, that is to say, the older and least vital parts of plants, 
must depend, in general, upon the insolubility or difficult solubility of 
a considerable portion of the ash ingredients that are contained in 
them. It is conceivable, indeed, that it might perhaps be due in part 
in some instances to the removal, z.e., the subtraction, from the wood 
or bark of certain organic matters, such as the coloring matters, that 
might be well-nigh destitute of ash ingredients. In order to test this 
point, I had a quantity of finely powdered fresh logwood leached with 
distilled water in the laboratory with the utmost care. To this end, 
a weighed quantity of the material was placed in a straight burette 
that had been plugged with a tuft of cotton, and it was there percolated 
with water, until the drops of water were colorless as they fell from 
beneath the wood. The apparatus was arranged so that atmospheric 
air was not in contact with the wood during the percolation. The 
leached wood was finally dried, and the amounts of ashes contained in 
it, as well as in the original wood, were determined. ‘The results of 
this experiment were as follows : — | 
The fresh wood regarded as having been dried at 110°* gave up 
13.04 per cent of its weight to the water. 
There was found 2.33, of ash in the leached wood, dried at 110,° 
and 2.32% of ash in the original fresh wood, dried at 110°. The 
dried leached wood amounted to 86.96% of the original dried wood. 
On evaporating the percolate to dryness at 110°, there was found 
dry “extract” to the amount of 12.72% of the dry wood taken, and 
this extract contained 3.74% of ash. 
In other words, it was found that 100 lbs. of the original dried wood 
contained 2.32 Ibs. of ashes, and that 2.03 lbs of these ashes were left 
in the 86.96 lbs. of wood that had been exhausted with water; while 
0.47 lb. of ashes was recovered from the solution. The fact that the 
sum of the last two quantities is slightly greater than the first is due 
to errors of manipulation, or of observation, such as are well-nigh in- 
separable from experiments of this kind. 
* As a matter of course, the wood actually operated upon was in its original 
air-dried state, in order that none of its constituents might be altered before 
the process of percolation had begun. But the amount of water that could be 
expelled at 110° was estimated in another portion of the wood, and the weight 
of this water was subtracted from the amount of the material that had been 
taken for the percolation. 
