Headden — Silicic Acid in Mountain Streams. 177 



The waters of Clear Creek are less representative than the 

 others, not because their gathering grounds are different or that 

 they have their courses through territories of different geologi- 

 cal formations, for such is not the case, but there is a very much 

 larger population within its area of drainage, the towns of Cen- 

 tral City, Black Hawk, Idaho Springs, Georgetown, and some 

 smaller towns being within it and above the point where the 

 sample was taken, which was from the Welch Ditch a mile 

 above the town of Golden. Further, mining and particularly 

 milling is actively carried on within its drainage area and on 

 its branches. The tailings of twenty odd mills are discharged 

 into its waters, to say nothing of the mine water which daily 

 mingles with that of the creek. The effect of these conditions 

 is plainly shown in the analysis but does not obscure the true 

 character of the water to any extent. I will not abridge the 

 analysis, though parts of it are superfluous for the present 

 purpose. 



Analysis of Water from Clear Creek, Sample taken from Welch Ditch, one 

 mile above Golden. 



Analytical 



results, 



SiO, 



S03 



CO, 



CI ._ 



Na,0 



K,0 



Li,0 



CaO 



SrO 



MgO 



ZnO 



AIO3 



Fe'A 



Mn30...... 



CuO 



PbO 



Ignition ... 



Per 



cent. 



17-953 



24-844 



6-870 



2-479 



7-073 



3-506 



trace 



21-041 



trace 



4-011 



0-207 



2-477 



1-916 



0-691 



trace 



none 



(7-491) 



Sum 100-559 



Oequiv. toCl -559 



Grs. 

 Imp. Gal. 



1-3644 

 1-8881 

 0-5221 

 0-1884 

 0-5375 

 0-2665 



trace 

 1-5991 



trace 

 0-3048 

 0-0157 

 0-1883 

 0-1456 

 0-0525 



trace 



none 

 0-5693 



7-6423 

 •0425 



Per 



Combined. cent. 



CaSO^ 42-252 



CaC03 6-483 



MnC03 7-707 



MgCl, 0-764 



KCl --. 4-017 



K,Si03 1-578 



Na^Si03 13-952 



Al,03 -. 2-477 



Fe,03 1-916 



ZnO _-- 0-207 



CuO trace 



PbO none 



Mn30^ 0-691 



Ignition (7-491) 



Sum 89-535 



Excess of SiO„ 10-464 



Total. 



Grs. 

 Imp. Gal. 



3-2111 



0-4927 

 0-5856 

 0-0581 

 0-3053 

 0-1196 

 1-0604 

 0-1883 

 0-1450 

 0-0157 

 trace 

 none 

 0-0525 

 0-5693 



6-8036 

 •7953 



99-999 7-5989 



Total... 100-000 7-5998 

 Total solids 7*6 grs. imp. gal. 



