It is a matter of current knowledge among geologists that various mineral substances of a greater or less degree of purity are at the present time being separated through the agency of natural processes from other substances or gathered from a previously widely disseminated state and placed by themselves. To this general process the term geological concentration has been applied. It is also well known from the study of mineral veins, residual earths, etcetera, that similar processes of concentration have been in operation throughout geological time, and that in obedience to a law of nature, as yet inscutible, whereby like seeks like, most mineral substances of commercial value have been segregated in veins, beds, and other deposits, and thus become available for human uses. No systematic attempt seems to have been made, however, to formulate the many and frequently highly complex processes by which the concentration of mineral substances . . .