68 BULLETIN 82 . 
TABLE LVIL—ANALYSIS OF SILT FROM QUEEN RESERVOIR, 
PROWERS COUNTY, COLO., SAMPLE TAKEN JAN. 23, 1903. 
PER CENT. 
Silicic Acid. 69.262 
Sulfuric Acid . 0.080 
Carbonic Acid. 2.819 
Phosphoric Acid.. 0 120 
Chlorin ...Trace 
Sodic Oxid. 1.401 
Potassic Oxid. 1.807 
Calcic Oxid. 4.904 
Magnesic Oxid. 1.081 
Ferric Oxid. 3 603 
Aluminic Oxid.10.428 
Manganic Oxid. 0.082 
Ignition . 4.283 
Total. 99.870 
Nitrogen, 0.075 per cent. 
§ 129. The elements of plant food contained in this are the 
potassic oxid, the phosphoric acid, and perhaps the lime and the 
organic matter. The exceedingly low content of nitrogen indi¬ 
cates that the value of the organic matter is small. This silt 
differs from the two previously given in carrying a little phospho¬ 
ric acid. This may come from the rock particles or from the shells, 
and may be from fragments of bone, a few of which were found 
in the silt. The chief value is in the potash, forty pounds per 
ton, but I can see but little difference between this potash, which, 
for the greater part at least, is contained in the felspar in the silt, 
and potash contained in any other finely divided felspar. The 
only question involved is the one of the degree of fineness. The quan¬ 
tity of potash is small, scarcely greater than that contained in an 
acre foot of some irrigation waters, especially those which have 
been stored—an acre foot of the Queen Reservoir water carrying 
72.3 grains per gallon, and the salts in solution containing 0.5 per 
cent of their weight of potassic oxid, contains fourteen pounds of 
potassic oxid, while a ton of the silt carries forty pounds, every 
whit of which has to be brought into solution. The three sam¬ 
ples of suspended matter, or silts, which have been presented rep¬ 
resent very different conditions, and yet the composition is essen¬ 
tially the same. We find the mineralogical constituents the same, 
and essentially the same percentages of potassic oxid in the two 
from the Poudre, but less in the third, representing the lower 
Arkansas, and in none of them is it high, 2.9 per cent in round 
numbers. 
§ 130. The fourth sample of suspended matter, of which I 
shall give an analysis, is of an entirely different nature. This 
material is not soil, or the natural products of decay on the sur¬ 
face of the crust, but refuse from mills, the products of 
decay formed in veins, comminuted gangue rock, slimed ore, etc., 
which is discharged into the water course and carried by the 
