26 
Bulletin 65. 
CONSIDERATION OF ANALYTICAL RESULTS. 
§ 50. There is no division of soil into surface and subsoil, ex¬ 
cept in the case of samples E and F, where E is the soil and F the 
subsoil. The mechanical and chemical analyses both show that 
there are marked differences. • 
The subsoil disappears entirely a few feet east of this point, and 
is entirely wanting at the point where sample D, the next on the 
east, was taken. The subsoil contains less decomposable silicates, 
corresponding to the soluble silicic acid, a considerable quantity of 
carbonate of lime, and a different mechanical composition. 
The surface soils vary more than would be expected, and not 
in the manner that a knowledge of their physical appearance and 
deportment under cultivation would lead one to anticipate. Soil A 
becomes heavily incrusted with alkalies, the incrustation reaching 
a thickness, at times, of one half inch, while soil E does not at any 
time show an incrustation and would not be considered as contain¬ 
ing any alkali, except for the marked amount of sulfuric acid ap¬ 
pearing in the analysis. The carbonic acid in both samples ap¬ 
pears to be in combination with calcium to the extent of about 50 
per cent, in the case of A, and probably a still greater extent in the case 
of E. This is the case if the water-soluble portion of the sample rep¬ 
resents the salts present in the soil, and no changes are induced by 
the long treatment with water necessary to remove all the soluble 
salts. We notice that the sulfuric acid in the samples of A and E, 
taken in October, is higher than in the samples taken in May. This 
mav be due to a transference of the sulfates from the subsoil to the 
soil, but taking the two series of samples, we see that only two sam¬ 
ples indicate an}' loss of sulfates, i. e., samples 0 and F ; and as al¬ 
ready suggested, the loss in F may account, in part, for the gain in 
E. 
§ 51. The carbonic acid does not give us any strong indica¬ 
tion that the season’s cropping and cultivation has eliminated much 
if any alkali from the soil, while the total soda present tends to 
show that the apparent diminution in the carbonic acid present is 
to be explained otherwise than by attributing it to any variation of 
the quantity of alkali. Samples E and D are from contiguous sec¬ 
tions. E shows no alkali on the surface, while D shows an abund¬ 
ance of it. If, for the sake of simplicity, we calculate the sulfuric 
acid as corresponding to sodic sulfate in the soil, we observe that in 
May it ranges from 0 87 to 1.63 per cent., whereas in October it 
ranges from 0.63 to 2.54 per cent., one sample only, C, showing a 
decrease from 0.90 to 0.63 per cent. In the case of the subsoil F, 
we have a decrease from 0.94 to 0.42 per cent, but in the surface 
soil E, corresponding to it, we have an increase from 0.92 to 1.45 
per cent. 
