COLORADO IRRIGATION WATERS AND THEIR CHANGES. II 
TABLE I.—ANALYSIS OF PORTION OF FELSPAR DISSOLVED 
BY WATER AND CARBONIC ACID IN TWENTY-TWO DAYS. 
Analytical 
Per 
Results. 
Cent. 
Silicic Acid ...... 
14.353 
Sulfuric Acid_ ... 
9.879 
Carbonic Acid_ _ . 
19.874 
Phosphoric acid. __ .... 
0.381 
Chlorin. _ _... 
3.170 
Aluminic Oxid _ ... .. 
1.119 
Ferric Oxid _____ 
0.136 
Calcic Oxid ... __ 
23.412 
Strontic Oxid. ...Heavy 
trace. 
Magnesic Oxid. . _ . 
1.919 
Potassic Oxid . .. 
11.279 
Sodic Oxid. _ .. 
6.491 
Lithic Oxid_ ..... 
Trace. 
Ignition 
25.337 
Sum __ _ 
117.370 
Less carbonic acid and ox- 
ygen equivalent to chlor- 
in * 
20.588 
Total__ 
96.782 
Per 
Combined. Cent. 
Calcic Sulfate. __ 16.806 
Calcic Carbonate_ 29.432 
Magnesic Carbonate_ 4.013 
Potassic Chloric!__ 6.668 
Potassic Carbonate_ 10.367 
Sodic Carbonate_ 3.736 
Sodic Phosphate__ 1.257 
Sodic Silicate_ 6.765 
Aluminic Oxicl__ 1.119 
Ferric Oxid_ 0.136 
Ignition_ 5.464 
Excess Silicic Acid_ 11.018 
Total_ 96.783 
* Note.—This residue was first dried on a water bath and afterwards 
in a water oven, as I knew from analyses already made that there was in 
all probability a considerable excess of silicic acid present in a most fa¬ 
vorable form to react with any alkaline carbonates present, which I wish¬ 
ed to avoid. I fear that a reaction between the silicic acid and these car¬ 
bonates took place during the long continued boiling and heating on the 
water bath necessary to evaporate the water to dryness, especially as the 
quantity of water was large (in this instance about twenty gallons), and 
the vessel in which the evaporation was carried on was small. It is 
also certain that on ignition, even at a gentle heat, the silicic acid reacts 
upon the carbonates, and perhaps other salts also, causing an excessive 
loss over that of moisture and organic matter. The ignition in this case 
was made very cautiously, but there is evidently an uncertainty about 
its correctness. I have repeatedly observed that in cases of ignition of 
such residues, even when there was not a sufficient excess of silicic acid 
to account for it, that the carbonic acid was completely expelled by a 
very gentle ignition. This may have indicated that the carbonic acid 
was in combination with lime as calcic carbonate; but the ignition was so 
gentle that I doubt whether it would have sufficed under ordinary con¬ 
ditions to have decomposed a corresponding amount of calcic carbonate. 
Other methods of determining this loss might have been adopted, but the 
amount of material at my disposal made ignition the most feasible one, 
it being quite certain that there was no loss of bases; and as there still 
remains an excess of acid, the result emphasizes this fact. I do not 
know in this case that the whole of the CO z was expelled, but I have as¬ 
sumed it to have been, and have accordingly taken it together with the 
oxygen equivalent to the chlorin found from the sum of the results 
obtained. 
§ 23. The preceding experiment does not stand alone, and 
was really not our principal one in this connection, but as the state¬ 
ment of others would add only cumulative evidence of the correct¬ 
ness of the conclusion that the source of the inorganic matter con¬ 
tained in the Poudre water is the felspar occurring everywhere 
