xlii ANALYSIS OF SOILS. 
7. Composition of K. 
Silica, with fine gravel consisting of fragments of Feldspar, Horn- 
blende, and other hard siliceous minerals,.._ ----.------- ae NOLS 
JATomin aeee Sateen tee RO aS OEE elo oe are eee 9 
Per (Oxidetotdlron, 52 --e Sess ee ecco sae eee oe ee = B80 
@arbonaterot limes sess ses) neon a= eae eee ere 29 
Phosphate of Wime geese a ceniana cia Sa eo ae ae ate ee .20 
77.04 
Water of absorption and organic matter,......--------.------- 23.66 
100.70 
It may be mentioned, as a very unexpected fact, that K. on being treated with heat and acids, and thus 
cleared of its soluble matter, left, in place of a fine siliceous sand, a gravel whose particles were generally many 
times as large as those of the sand of the soils, while they differed still more from the sand, in not being com- 
posed of quartz. but of feldspar, hornblende, epidote, &e.—minerals which are heavier and less frangible than 
quartz. The superior toughness and specific gravity of these substances would, therefore, serve to impeae their 
comminution and transportation by the action of the sea, and they might be expected to form accumulations 
upon the sides and bottoms of rivers and inlets, where their gradual disintegration and decomposition, and 
constant intermixture with organic matter, would convert them into the clay-like aggregates such as we find in 
specimen K.+ 
The operation of this marsh-mud as a manure upon the soils under examination, depends not merely on the 
saline, organic, and calcareous matter it contains, but is referrible, in part, to the large proportion of the alumi- 
nous or argillaceous ingredient, whose mechanical effects on sandy lands in promoting the retention of moisture, 
are eminently beneficial. 
The very small proportion of carbonate of lime in the marsh-mud proves that as a mineral amendment for 
soils deficient in calcareous matter, it cannot be substituted for marl, or shells; one or the other of which ought 
to be employed in conjunction with the mud. 
The saline matter of the marsh-mud, A. and B. is abundant. When treated with their weight of pure wa- 
ter, the fluid is strongly impregnated with all the soluble substances found in sea-water, and in addition, with 
traces of sulphuretted hydrogen. The stimulating effects of the salts, as well as their mechanical agency in 
favoring the absorption of moisture from their deliquescing properties, snust be apparent. 
The soil H, is remarkably distinguished from all the rest by the amount of carbonate of lime it contains.— 
This is plainly in the condition of broken shells, their fragments being discernible with the naked eye. In 
adaptation to the cotton plant, this soil is described as surpassing every other. I am disposed to ascribe this 
superiority to the carbonate of lime, since in other respects the soil scarcely differs from many others. 
May not the peculiar fertility of new sea-island cotton land be owing to the proportion of comminuted shells 
natural to such soils, and the deterioration of these lands under long cultivation, ascribable to the exhaustion of 
carbonate of lime? 
The addition of a marsh mud, which abounds in a gravel of feldspar and hornblende, like K, must undoubt- 
edly be greatly superior to one whose mineral basis is only siliceous sand. This consideration appears to me 
* After the Alumina had been separated from the oxide of iron and phosphate of lime by an alkaline ley, the oxide of iron and 
phosphate of lime were washed, dried and weighed. They were then ignited with carbonate of soda, in order to decompose the 
phosphate of lime. Acetic acid was added until all the lime was dissolved. ‘The per oxide of iron, which was not attacked by the 
acid, was now separated and weighed. The difference between its first and last weight, gives the amount of phosphate, 
7 On heating a fragment of K to whiteness in a crucible, it was converted into a well fused and very hard brick-like compound. 
’ 
