3. The more popular teaching of today is, that matter existed in a highly heated state in the form of a diffused cloud. Steel, in his “Fourteen Weeks in Geology,” suggests that “From unknown causes, this cloud-matter began to revolve about a center or sun. This nucleus drew matter direct to itself from all parts of our system. Other portions revolving were thrown off, and formed new centers for planetary gathering, as they respectively took up their orbicular march about the sun. This fiery mist is supposed to have come together in a heated state. The planets, at least, have since been cooling, though as yet having but a thin crust.” To this theory of primeval heat, in some form, all our text books conform. A theory so long and so universally accepted might be supposed to have some solid facts upon which to rest. But really it has less to sustain it than had the Ptolemaic theory of Astronomy: that, at least, had observation in its favor, but this fails even here. It is a curious circumstance in this guess work of results, that whether heat is made to increase on an average one degree in fifty feet, as given by many geologists, or one degree in one hundred feet, as given by others, precisely the same results are reached, viz., fifty miles crust, and intensely heated matter beyond. This assumption is based upon the supposed fact that the internal heat traverses the rock by conduction. If this were true, then the degree of heat gained in any one hundred feet of rock, as you descend into the Earth’s crust, would be the approximate measurement of any other hundred feet in the same shaft; but the reverse of this is true. No two measurements seem to be alike. The miner, as a practical geologist, in this regard knows that this heat is generally caused by chemical action of the rock upon which you have let in air or water, or both. This heat is found to vary according to nature of the rock which you expose. If the rock is rich in pyrites of iron or lime, in any of its numerous forms, then disintegration is abundant and much heat is generated; but, on the other hand, where all disintegrating elements are wanting, there is no perceptible increase of heat.