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BULLETIN OF THE BUSSEY INSTITUTION. 51 
their true worth in the face of these disturbing influences. It is prob- 
able, moreover, that the materials thus tested really differed widely 
among themselves as regards the amount of wood-ashes contained in 
them. It is well known that a large proportion, if not most, of the 
coal-ash obtained from domestic fires is mixed with more or less wood- 
ashes, derived from the kindling materials or from wood used’ in con- 
junction with the coal. It often happens, indeed, that the proportion 
of wood-ashes is so large that the mixture has from that cause decided 
value as a fertilizer. 
In consequence of this lack of purity, so to speak, of the ashes used, 
many of the field experiments which have been made hitherto have 
had little or no bearing upon the question as to the value of coal-ashes. 
Such tests have been useful, no doubt, in so far as they gave informa- 
tion concerning the ashes of the particular house or fire whence they 
were procured, but they lack general significance. There can be no 
doubt, however, but that the field experiments, taken all together, 
have proved pretty conclusively that coal-ashes, when free from wood- 
ashes, have no great fertilizing power. And, in fact, there seems to 
prevail among the farmers of New England a very generally diffused, 
though perhaps a not very firm or well-defined belief, that coal-ashes, 
by themselves, have no agricultural value whatever, excepting in 
so far as they may be made to serve as well as an equal quantity 
of sand or gravel for the mechanical improvement of low-lying peaty 
soils. 
In the hope of gaining some definite knowledge which might serve 
to settle the question, I have subjected coal-ashes to still another 
method of investigation ; to the method, namely, of growing plants 
in a considerable number of pots of ashes treated in such wise that 
.in each pot the ashes might supply to the plant, if they could, some 
one or more of the ingredients needed for its growth. The ashes 
employed in these experiments came from the burning of hard white- 
ash anthracite coal from Pennsylvania in two of the furnaces used for 
heating the stone building of the Bussey Institution. Care was taken 
so to manage the fires that no wood-ashes could by any possibility be- 
come mixed with the ash of the coal. The ashes were sifted through 
a sieve carrying four meshes to the inch, and were kept protected 
from dust and fumes. The experiments were conducted in the glass- 
house, or conservatory, which constitutes one room in the Bussey 
Laboratory. 
