Headden — Silicic Acid in Mountain Streams. 



179 



Analysis of Water from the Running Lode Mine. 



nalytical 

 results. 



Per cent. 



Combined. 



Per cent. 



SiO, 



. 11-298 



CaSO^ _. 



39-835 



803^. 



. 23-423 



CaC03 



13-610 



CO, 



. 16-099 



MgC03 



13-724 



CI. 



1-936 



K,CO, 



2-433 



Na,0 



8-262 



Na.Ca 



5-276 



KO 



1-659 

 trace 



NaCl 



Na,Si03 



3-195 



Li;o _. 



6-861 



CaO 



. 24-039 



Fe,03, Al,03.. 



0-J02 



SrO.- 



trace 



Mn30, 



0-120 



MgO 



6-563 



Ignition ....._ 



(6-935) 



Fe,0,, A1A-. 



•102 







Mn30, 



•120 



Sum 



. 92-091 



Ignition 



_ (6-935) 

 . 100-436 



Excess of SiO, 

 Total 



7-915 



Sum 



100-006 



= C1 



-436 







Total 



. 100-000 





Total solids 23-0 grs. per imp. gal. 



On combining the results of this analysis we find here as in 

 the other cases a decided excess of acids which can scarcely be 

 supposed to be due to other than free silicic acid. 



The uniformity of these results indicate that these waters are 

 entirely normal for the conditions under which they occur, i. e. 

 within or in contact with granite or rocks rich in felspar. In 

 this case the rocks do not belong to the eruptives, but I cannot 

 see why the class of rock in which the felspar might occur 

 should make any material difference in the general result. The 

 composition of the residues might be considered as suggesting 

 a lime mineral other than felspar as having furnished the min- 

 eral matter to the waters, but local conditions make it very 

 probable, and direct experiment will, I think, establish it, that 

 the felspars do in these cases furnish the mineral matter to 

 these waters. I do not by any means intend to claim that the 

 felspars are the only minerals acted on by water and carbon 

 dioxid, but simply that our waters represent the products of 

 such action and it is evident that neither high temperature nor 

 great pressure have played any part in producing the solutions. 

 These two factors have been appealed to to account for the 

 excessive silicic acid in the geysers and hot springs, but my 

 results indicate that these are not necessary to account for the 

 presence of the silicic acid. These points seem to me to have 

 been well tested in some experiments which I have made with 



