346 BULLETIN OF THE BUSSEY INSTITUTION. 
burning the heaps are not spread, except the little that is done 
towards spreading them by the plough and the harrow in the cul- 
tivation of the soil. . . . Thus accident furnishes the means of 
much more correct information of the effects of fire on soils than 
any chemical experiments that have been or perhaps ever will be 
made. ‘This. being the case, the backwood’s farmer at one com- 
prehensive view may readily see the effects produced by every dif- 
ferent grade of burning and on every different kind of soil. He 
may likewise readily discover the effects produced by the differ- 
ent grades of burning, by comparing what takes place where the 
log-heaps, brush-heaps, etc. were burned, with what happens in 
the grounds around them which have not been subjected to the 
burning. The salts contained in the ashes where the heaps were 
burned, especially where the log-heaps were consumed, keep the 
soil so moist for some time after the grounds have been cultivated 
that until I have got near enough to investigate the cause of this 
moisture I have sometimes thought that it proceeded from spouts 
or feeble springs. ‘This moisture causes the crops to be as luxuri- 
ant on sandy soils as on clay. It counteracts the injurious effects 
produced by too great evaporation, which generally takes place in 
sandy grounds after they have been robbed by burning or an inju- 
dicious cultivation of the greater part of the animal and vegetable 
matter that had previously existed in them.” 
I have myself seen, upon the Plain-field of the Bussey Institu- 
tion, this compacting effect of carbonate of potash produced in 
very marked degree. A plot that had been dressed exceptionally 
heavily with wood-ashes during four consecutive years was finally 
ploughed, in dry summer weather, together with the rest of the 
field. It then appeared that the soil of this particular plot was so 
firmly bound that a yoke of oxen had considerable trouble in drag- 
ging a plough through it, and that the furrow where it crossed this 
plot was a mere mass of large hard lumps or clods, though the soil 
of the remainder of the field was mellow enough and was ploughed 
without any difficulty. Yet through all the years of the experi- 
ment the plot now in question had borne luxuriant crops and had 
manifestly been better supplied with moisture than any of the 
other plots in the vicinity. I could not see any reason for beliey- 
ing that the well-known power of carbonate of potash to attract 
water from the air had anything to do with the appearances here 
described. On the contrary, it is highly improbable that the easily 
soluble carbonate could have remained long, as such, in the soil of 
