and Time of Digestion in the Eatraction of Soils. 21 
_ With the aid of a Bunsen’s filtering apparatus we can, by . 
this method, complete an analysis in five days, exclusive of 
digestion ; and three analyses may be in progress at the same 
time 
The substance experimented upon was a subsoil, a typical 
representative of the best yellow loam uplands of Mississippi, 
from the table lands of Benton Co., Miss. ; No. 219 of the Sur- 
vey Collection.* 
and ten days, of the same soil with the same large excess of aci 
of 1-115; all precautions being taken to accomplish each anal- 
ysis as nearly as possible under the same circumstance 
For the di 
'nsoluble residue, and each evaporated to dryness separately 
Bre reunited in solution, to prevent any further action of the 
aci 
This result points to the conclusion, that while lime and mag- 
hesia (being readily dissolved) are probably present chiefly as 
carbonates or hydrocarbonates, potash as well as alumina, and 
to some extent lime, are present as silicates, and for that reason 
are not as fully RRESE 4 by acid of low strength as by that of 
on although the former acts more powerfully than that of 
The latter fact (the coincident result of two on ge though 
unlooked for, is not without analogies, although its precise 
* The analysis of : : . is given in Hilgard’s Re- 
Port, 1860, oe the subsoil of a neighboring tract wees : | 
