REVIEW AND CONCLUSION. 369 
Boussingault has analyzed in this manner a soil from 
Calvario, near Tacunga, in Equador, South America, which 
possesses extraordinary fertility. 
He found its composition to be as follows: 
Nitrogen in organic combination, 0.248 
Nitric acid, 0.975 
Ammonia, 0.010 
Phosphoric acid, } 0.460 
Chlorine, 0.395 
Sulphuric acid, 0.023 
Carbonic acid, ; : traces 
Potash and Soda, Soluble in acids. 1.030 
Lime, 1.256 
Magnesia, 0.875 
Sesquivxide of irou, 2.450 
Sand, fragments of pumice, and clay insoluble in acids, 83.195 
Moisture, 3.150 
Organic matters (less nitrogen), undetermined substances, 
and loss, 5.938 
100.000 
This analysis is much more complete in reference to ni- 
trogen and its compounds, than those by Baumhauer al. 
ready given (p. 362), and therefore has a peculiar value. 
As regards the other ingredients, we observe that phos- 
phoric acid is present in about the same proportion; lime, 
alkalies, sulphuric acid, and chlorine, are less abundant, 
while magnesia is more abundant than in the soils from 
Zuider Zee. 
The method of analysis is a guarantee that the one per 
cent of potash and soda does not exist in the insoluble 
form of feldspar. Boussingault found fragments of pumice 
by a microscopicexamination. This rock is vesicular feld- 
spar, or has at least a composition similar to feldspar, and 
the same insolubility in acids. 
The inert nitrogen of the humus is discriminated from 
that which in the state of nitric acid is doubtless all assim- 
ilable, and that which, as ammonia, is probably so for the 
most part. The comparative solubility of the two per 
cent of lime and magnesia is also indicated by the analysis, 
16* 
