Percentages of Ash and Phosphorus in Wood and Charcoal. [Volume: 8, Issue: 2, 1888, pp. 81-97]

82

UNITED STATES ASSOCIATION OF

[VOL. 8,

m. m. (11 inches) which rested, convex part up, on two wires
placed across the dishes. By thus separating, charring and incinerating, the loss of ash, through small particles being carried away
by the gases, was completely avoided. The final combustion was
made in platinum crucibles.
The different samples of wood consisted of cubes, which were
kept, for at least a month, in a room with a temperature of 20~
Centigrade (68~ Fahrenheit). before being weighed. The degree
of dryness which the different samples obtained, was found by
heating them to 120~ Centigrade (248~ Fahrenheit), at which temperature the loss of hygroscopic water in all kinds of wood, and
in the bark of the birch, ash, etc., was 10 per cent., while for the
bark of the pine and fir the loss was 14 per cent.
As, however, in practice the so-called "air-dried" wood contains about 20 per cent. of hygroscopic water, we make our calculations on the basis of 20 per of water for wood as well as for the
bark
For charring and incinerating about one thousand grains of the
above described wood cubes and about five hundred grains of the
bark were generally used.
The ash obtained after being weighed was kept for analysis in
small test tubes with tight-fitting corks. The greatest amount of
phosphoric acid is found in the bark, and after that in birch wood.
In the pine and fir we find six times as much phosphoric acid in
the.surface wood as in the center wood. Ample opportunity for
studying the amounts of ash and phosphoric acid is given in
Table A.
In these tables the weight of charcoal is assumed to be 20 per
cent. of that of the wood from which it is made. As, however,
wood used for charring on a large scale usually contains more
than 20 per cent. of hygroscopic water, the amounts of charcoal
and consequently of the phosphorus are a little high. The. difference will, however, for practical purposes have little influence.
THE INFLUENCE OF THE SPECIES OF WOOD ON THE AMOUNTS
OF ASH AND PHOSPHORUS.
In Table B, which is a compilation of average figures from Table
A, we find for wood of the trees proper, increasing amounts of ash
in the following order: Pine, fir, birch, alder and ash. But tak