the ethereal solution is allowed to evaporate. The residue (phenol) is
weighed directly, and from this the percentage can be ascertained. By
this method of extraction, the oil of turpentine, resins, etc.,
contained in _Pinus sylvestris_ do not pass into solution, because
they are insoluble in water, even when boiling; what passes into
solution besides phenol is a little tannin, which is practically
insoluble in ether.

From this investigation it will be seen that phenol exists in various
proportions in the free state in the leaves, stem, and cones of _Pinus
sylvestris_, and as this compound is a product in the distillation of
coal, and as geologists have to a certain extent direct evidence that
the flora of the Carboniferous epoch was essentially crytogamous, the
only phænogamous plants which constituted any feature in "the coal
forests" being the coniferæ, and as coal is the fossil remains of that
gigantic flora which contained phenol, I think my discovery of phenol
in the coniferæ of the present day further supports, from a chemical
point of view, the views of geologists that the coniferæ existed so
far back in the world's history as the Carboniferous age.

I think this discovery also supports the theory that the origin of
petroleum in nature is produced by moderate heat on coal or similar
matter of a vegetable origin. For we know from the researches of
Freund and Pebal (_Ann. Chem. Pharm._, cxv. 19), that petroleum
contains phenol and its homologues, and as I have found this organic
compound in the coniferæ of to-day, it is probable that petroleum in
certain areas has been produced from the conifers and the flora
generally of some primæval forests. It is stated by numerous chemists
that "petroleum almost always contains solid paraffin" and similar
hydrocarbons. Professors Schorlemmer and Thorpe have found heptane in