What doth it mean and whither tendeth, This life—this death—this world—the whirling stars? Why do we live to-day—to-morrow endeth Our half dreampt dream behind the twilight bars? [Illustration] The Phosphates of Tennessee By H. D. RUHM Mr. Ruhm is one of the pioneers in the phosphate field and his paper on this subject is the work of an expert.—Ed. The phosphates of Tennessee occur chiefly, in fact, almost entirely, in the strata representing the Silurian and Devonian geological ages, or, more properly, in the former, and in a transition period between the two. The Silurian age was essentially the age of shell fish, animals with their skeletons entirely on the outside of their bodies. The deposits of countless millions of these shell fish and their remains form the immense beds of limestone representing the Silurian age. The composition of these shell fish was carbonate of calcium, or “lime,” and hence our common limestones are calcium carbonate. [Illustration: _Fig. A._ _Fig. B._] The Devonian age was the age of fishes or vertebrates, and owing to the need of greater elasticity of their bones and smaller weight, they are composed of phosphate of calcium, or “lime.” Far back in the Silurian age the “Hand that fashioned all things well” began to change some of these shell fish to provide for the future order of things, so that their outside skeletons, or shells, were composed of phosphate of lime instead of carbonate. These two commingling, the resultant beds of rock became somewhat phosphatic and formed the “phosphatic limestones” of the Silurian age. In some places the phosphate shells were in considerable proportion, and subsequent erosion, proper underground drainage and leaching, dissolved out the carbonate of lime to greater or less extent and left the “brown phosphate” of the middle basin, varying in grade according to the preponderance of phosphate shells in the original deposit and the extent of the subsequent leaching. Meantime the transition stage between the two ages had been reached and the resulting deposit spread over the central basin and the highland rim in the form of a thin blanket of varying thickness and quality of the so-called blue rock, which is blue, brown, gray and black, according to the coloring matter present or absent, composed of a preponderance of microscopic shell fish with skeleton composed of phosphate of lime, but mixed with enough carbonate to make the resulting mass vary from sixty-five per cent to as high as eighty per cent calcium phosphate.