28 
Bulletin 65. 
cent. This shows nothing, because the samples were not taken from 
points near enough together. The samples of the third season were 
not taken for the purposes of such a comparison, and merely chance 
to serve even in this measure. The fact that the nitrogen content 
in the October samples was higher than in the May samples, has 
but little if any dependence upon the beet crop, but was possibly 
very dependent upon the cultivation and irrigation. It is, we may 
say, a distinct crop, which increases with favorable conditions of 
season and soil; and our analyses simply show that there was more 
in the soil on October 20 than on May 13, regardless of what had 
been removed by the crop or dissolved out by water. 
§ 53. The effect upon the organic matter in the soil did not 
seem to be very decided, but at the end of three seasons there was 
a gain, not so large, however, as I expected, the tops of two crops of 
beets and a heavy coating of manure having been added to one half, 
on alternate sections, of the plot. 
§ 54. The analyses, as we ought to expect, do not show us the 
changes which have really taken place. This plot, for instance, has 
improved most wonderfully in its quality, and the analyses do not 
and cannot measure these improvements. It is not a question of 
composition, but one of conditions. 
SOME RESULTS DUE TO THE PRESENCE OF FELDSPAR. 
§ 55. The consideration of the mineralogical constituents of 
the soil renders it evident that in our case we have to deal with the 
mineral feldspar, and indefinite decomposition products of this min¬ 
eral, mixed with decaying organic matter. The agricultural anaty- 
sis of the soil will yield results which will vary with the fineness of 
the feldspar particles the character of the decomposition prod¬ 
ucts present, with slight variations in manipulation, and with other 
conditions which one cannot foresee. The minor variations, for in¬ 
stance in the percentages of potash found, as in case of sample A, 
1.495 and 1.528, or in B, 1.003 and 0.978, may arise from such 
causes, and not depend in any way upon cropping or cultivation. 
§ 56. As the solubility of feldspar in dilute acids is a well 
recognized property of this whole class of minerals, the results of 
the mineralogical study of these samples was somewhat disconcert¬ 
ing, not in regard to the value of such analyses in general, but of 
my analyses in particular. The abundance of this mineral 
present, the abundance of potash soluble in dilute acid, and 
the impossibility of washing out all the lime, soluble in dilute 
hydrochloric acid in any reasonable time, led me to experiment with 
orthoclase, powered so fine that the whole mass would pass through 
a sieve with one millimeter mesh, because this is the conven¬ 
tional size of the particles of fine earth. Thirty-three per cent, of 
