Mathematical and Physical Papers. 205 



THE GENESIS OF GOLD IN MINERAL VEINS AND 



PLACERS. 



By J. T. LovEWELL, Topeka. 



T N our limited sphere of observation we can know but little of the 

 J- internal structure of the earth. Assuming it once to have been 

 a molten liquid mass, it is natural to conclude that the denser con- 

 stituents would be grouped nearest the center, and as the earth 

 cooled, and as rifts were made by contraction of the solid crust 

 down to the liquid interior, the molten rock extruded through 

 these cracks would contain more of the heavy metals. Were the 

 fissure deep enough the outflow might be metals like gold or plati- 

 num, or even heavier substances, unknown on the earth's surface. 



The hypothesis of a liquid interior has little to support it, and 

 whatever may be the temperature it is certain that the earth's in- 

 terior is a mass of great -rigidity, and we can form little conjecture 

 how its elements are combined and grouped. 



The fact of rifts in the crust may be admitted, and that these 

 were ways of exit of a molten magma which filled the crevices and 

 flowed out as it does to-day in volcanoes. 



But these fissures are filled not only with igneous rock but with 

 materials crystallized out of solutions. One of the commonest of 

 these crystallized substances is quartz, either alone or intermixed 

 with oxides, sulfides, etc., of various metals, or with the metals un- 

 combined, as gold and silver. The solvent which carried this silica 

 and these metals is doubtless water, which comes nearest of any 

 liquid to being the universal solvent. In explaining earth problems 

 we must always keep in mind the ever-present water, which, first 

 enveloping the earth as a vapor, must have been continually exert- 

 ing its solvent powers on whatever was beneath and around it. Not 

 only does it act on surfaces but it penetrates the interiors of sub- 

 stances, and its energy is increased by the gases, such as chlorine, 

 with which it may be saturated, and by the high temperature, at 

 which it must always have existed. 



If we start now with the situation when the igneous rocks and 

 crystallizations fill the fissures and outcrop on the surface of the 

 earth, we find the water acting in another role. It is now to grind 

 down the surface by glacial action, to plow out the valleys by ero- 

 sion, and to sift the fine from the coarse, the heavy from the light, 

 till the deposits are brought to their present condition. The gold 



