182 Headden — Silicic Acid in Mouiitairi Streams. 



Without discussing the probable combinations which actually 

 existed in solution, it is evident that an unduly large amount 

 of silica had been taken up. The result presented by this 

 analysis represents the action of rain or snow water under 

 ordinary conditions. The carbonic acid introduced was mod- 

 erate in quantity and was thoroughly mixed w^ith the air before 

 being drawn through the water. Both the carbon dioxid and 

 air were well washed ; this was done to prevent the introduction 

 of organic matter, chlorin or other impurity with the air. 



The second experiment was conducted differently. A quan- 

 tity of felspar was powdered, passed through a 100 mesh sieve 

 and treated with water saturated with CO2, without any attempt 

 to remove the iron derived from the buckboard by means of 

 the magnet or otherwise. The containing vessels were sealed 

 and allowed to stand for twenty-two days with frequent shaking. 

 When the vessels were unsealed some of them showed a little 

 pressure. As the iron derived from the buckboard had very 

 largely gone into solution, I passed a current of air through the 

 vessels before I filtered off the felspar — this was a mistake. 

 The iron was easily oxidized and precipitated. It required 

 only about forty-five minutes for the oxidation to become appar- 

 ent to the eye, but the air current was continued for forty hours 

 when the whole was filtered and evaporated in platinum vessels, 

 the same precautions being taken as in the previous case. The 

 analysis of this residue resulted as follows : 



Analysis of Residue — Second Experiment with Felspar. 



Analytical 

 results. 



SiO, 



S03 



CO, 



PO _. 



Per cent. 

 ... 14-353 



9-879 

 .._ 19-874 



0-381 



Combined. 



CaSO, 



CaC03... 



MgC03 



KCl 



KCO 



Per cent. 

 .- 16-806 

 .. 29-432 

 - _ 4-013 

 .- 6-668 



CI ' 



3-170 

 1-119 



-. 10-367 



Al 



Na,C03 



NaPO 



-. 3-736 



Fe 



0-136 



_- 1-257 



CaO 



SrO 



... 23-412 



heavy trace 



1-919 

 ... 11-279 



Na,Si03 



AlO 



.. 6-765 

 .. 1-119 



MgO.. 



KO ........ 



2^3 

 FeO 



._ 0-136 



Ignition 



Excess of SiO, . 



Total 



... 5-464 



NaO .- 



6-491 



.. 11-018 



Li 



trace 





Ignition 



... 25-337 



.. 96-783 



Sum 



LessCO,-t-0= 



. . 117-370 



= C1 20-588 





Total 



96-782 





