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BULLETIN OF THE BUSSEY INSTITUTION. 351 
tion of the lime carbonate in carbonic acid water that would natu- 
rally form in a nitre-bed is distinctly though feebly alkaline, and 
there would be no such risk of this solution becoming too strong 
as there might be if a source of carbonate of potash were at hand. 
The point is not without interest since it bears directly on the much- 
disputed question of the relative value in agriculture of leached 
and ‘‘live” ashes. It is not improbable, for instance, that in some 
situations where the exciting of nitrification in a soil may ensure 
the success of a crop, an abundant dressing of leached ashes may 
’ do almost as much good as wood-ashes would have done. So too 
the singular endurance —?. e. the long-continued fertilizing action 
— exhibited by ashes in many localities probably depends in good 
part on nitrification which the ashes favor and support. It is no- 
ticeable that both live and leached ashes have been heartily rec- 
ommended as applications for Indian corn, —the one in some 
localities and the other in other places; and although the success 
of this crop probably depends in great measure and generally on 
nitrification of the soil-nitrogen, it is not improbable that the first 
action on the soil-humus of the alkali in live ashes may be of im- 
portance in some cases; perhaps by preparing the humus for rapid 
nitrification, if for no other reason. Herein may perhaps lurk one 
difficulty as regards the question of estimating what the real value 
of potassium carbonate would be if it were taken by itself and used 
in comparison with other potash-salts. It is probable enough that 
wood-ashes may do several kinds of work while the powers of pure 
carbonate of potash may be less varied and those of the neutral 
potash-salts be more limited still. 
C. — Utility of mixtures of Stassfurt potash-salts and lime. 
From what has been said already of the alkali-lands of Califor- 
nia, it is to be inferred that mixtures of chloride of potassium and 
lime must be useful additions to some kinds of soils, since when 
fitly placed such mixtures may work to improve the water-holding 
condition of the land and to make the soil-nitrogen available for 
crops. The last-named point has already been discussed to a cer- 
tain extent in this Bulletin (vol. I. p. 391). It may readily be 
illustrated by referring to what is known of the reactions which 
occur when common salt and lime come in contact with one an- 
other in porous earth, and there is no lack of evidence to attest the 
significance of this reaction. Since the beginning of history con- 
siderable quantities of an impure carbonate of soda have been 
