THE ASH OF PLANTS. 164 
gredients, viz. chlorine and sulphuric acid, snould be re- 
duced to uniformity, and the analyses then be recalculated 
to per cent. 
In the first place, however, we are not warranted in 
assuming that the “excess” of chloride of potassium, car- 
bonate of potash, etc., deducted in the above analyses 
respectively, was all accidental and unnecessary to the 
plant, for, under the influence of an increased amount of a 
nutritive ingredient, the plant may not only mechanically 
contain more, but may chemically employ more in the 
vegetative processes. It is well proved that vegetation 
grown under the influence of large supplies of nitrogenous 
manures, contains an increased proportion of nitrogen in 
the truly assimilated state of albumin, gluten, etc. The 
same may be equally true of the various ash-ingredients. 
Again, in the second place, we cannot say that in any 
instance the minimum quantity of any ingredient neces- 
sary to the vegetative act is present, and no more. 
It must be remarked that these great variations are only 
seen when we compare together plants produced on poor 
soils, 7. e. on those which are relatively deficient in some 
one or several ingredients. If a fertile soil had been em. 
ployed to support the buckwheat plants in these trials, we 
should doubtless have had a very different result. 
In 1859, Metzdorf, ( Wilda’s Centralblatt, 1862, 2, p. 
367,) analysed the ashes of eight samples of the red-onion 
potato, grown on the same field in Silesia, but differently 
manured. 
Without copying the analyses, we may state some of 
the most striking results. The extreme range of variation 
in potash was 54 per cent. The ash containing the high- 
est percentage of potash was not, however, obtained from 
potatoes that had been manured with 50 pounds of this 
substance, but from a parcel to which had been applied a 
poudrette containing less than 3 pounds of potash for the 
quantity used. 
