But, by what process, or operation of nature, came these seams, or veins of gold or other metals, to be thus deposited? Was it by the agency of fire, or by water and alluvion? I think it probable that both may have been at work, being the two greatest solvents in nature, and, at the same time, the greatest chrystalizers. Perhaps metallic _ores_ may be the work of alluvion, and the production of pure _metallic_ substances—that of heat. With respect to gold, I think the latter theory is the more reasonable, as it is always found in a pure state, while the quartz (or pure silex) in which it is contained may be alluvial, and one pf the earliest deposites from the decomposition of the ancient unstratified mass. But where shall we seek for the original supply of the precious metal? How is it formed, or whence has it been extracted by the agency of heat? It is not enough to say that, like other metals, it is found diffused throughout all nature, for an appreciable quantity of gold has been extracted from violets. In my opinion, it exists on the original unstratified mass, in imperceptible proportions; but those proportions varying a different places, other metals being more or less abundant. The greater proportion of our soils, according to Sir Humphrey Davy, is formed by the decomposition of the original granite; and this accounts for diffusion of gold in minute particles, which may be taken up by plants, and enter into the composition of organized bodies. If then, the unstratified rock is the original seat of the metal, but in particles infinitely minute, it may have been separated by a very high degree of heat, by which it would be sublimated or volatilized, and thus carried upwards by chemicoelectric force, by a process resembling distillation. In this way, it would penetrate the quartz rock, or be condensed in the spaces of the laminated strata, such as the talc, schist, or mica slate. Such is the theory of Trimmer, Buchland, and other modern mineralogists. Lyall says—“granite, syenite, and those porphyries, which have a granite form structure, in short all plutonic rocks (rocks having undergone the action of heat) are frequently observed to contain metals, at or near their junction with stratified formations. On the other hand, the veins which traverse stratified rocks are, as a genera] law, more metalliferous near such junctions, than in other portions. Hence it has been inferred that these metals may have been spread in a _gaseous form_, through the fused mass, and that the contact of another rock, of a different state of temperature or sometimes the existence of rents in other rocks in the vicinity, may have caused the sublimation of the metals.”