As it regards their production, the present state of geological and chemical science suggests _three_ theories, each of which would be adequate to the object. It is necessary to premise that _water_ is a common agent in each of the three theories. 1. The splendid discoveries of Sir H. Davy, in regard to the _bases_ of the earths, demonstrating them to be _metallic_, and the earths merely _oxides_ of those metals, have led to the conjecture, _that these metals exist in nearly a pure state in the interior of the earth_; of course the _crust_ of the earth is composed of the various metallic oxides. It is well known that many of these metals _take fire on coming into contact with water, as potassium, sodium, &c_; and _all of them oxidize rapidly on meeting with water and air_, and thus _large quantities of hydrogen gas would be evolved_. This theory is so reasonable, in view of the _combustibility_ of metals, and so conformable to science, that we almost decide it is true, without further examination. But, in order that its demonstration should be clear, it must first be shown, _that the metals do exist in nearly a pure state in the interior of the earth_: and then, _that they are accessible by water, or air, or both_. The first point can only be rendered _probable by analogy_. We _know_ that the earths which are found in the crust of our planet are _metallic oxides_. It is very natural to suppose these metals existed in a pure _metallic state at the creation, as well at the surface as at the centre_; as all other bodies most probably existed in an elementary and uncombined state when God first produced them. From this supposition it is easy to see, that when water and air came into action, which would be at the earth’s surface, these metals would be rapidly oxidized, thus forming the earths. But as this process would commence at the _surface_ of the earth, and _tend towards the centre_, it is evident its _progress would be arrested by its own action_. For the _accumulation of the earths_, by the oxidation of the metals, would gradually form the _superincumbent crust_, which would act as a _barrier_ to the water and air, preventing their contact with the metals in the interior, _which_, of course, _would not be oxidized_.