Pinus, which heptane yielded primary heptyl-alcohol, and
methyl-pentyl-carbinol, exactly as the heptane obtained from petroleum
does (_Annalen de Chemie_, ccxvii., 139, and clxxxviii., 249; and
_Berichte der Deutschen Chemischen Gesellschaft_, viii., 1649); and,
further, petroleum contains a large number of hydrocarbons which are
found in coal. Again, Mendelejeff, Beilstein, and others (_Bulletin de
la Societe Chemique de Paris_, No. 1, July 5, 1883), have found
hydrocarbons of the--

C_{n}H_{2n2+}, C_{n}H_{2n-6},

also hydrocarbons of the C_{n}H_{2n} series in the petroleum of Baku,
American petroleum containing similar hydrocarbons.

I think all these facts give very great weight to the theory that
petroleum is of organic origin.

On the other hand, Berthelot, from his synthetic production of
hydrocarbons, believes that the interior of the globe contains
alkaline metals in the _free_ state, which yield acetylides in the
presence of carbonic anhydride, which are decomposed into acetylene by
aqueous vapor. But it has been already proved that acetylene may be
polymerized, so as to produce aromatic carbides, or the derivatives of
marsh gas, by the absorption of hydrogen. Berthelot's view, therefore,
is too imaginative; for the presence of _free_ alkaline metals in the
earth's interior is an unproved and very improbable hypothesis.
Byasson states that petroleum is formed by the action of water,
carbonic anhydride, and sulphureted hydrogen upon incandescent iron.
Mendelejeff thinks it is formed by the action of aqueous vapor upon
carbides of iron; and in his article, "Petroleum, the Light of the