was woven out of prosaic material it has
been this industrial development of modern chemistry.

But although the results are striking enough when thus summed up, and
although the industrial importance of all this work will be conceded by
those who have the welfare of the country in mind, the paths which the
pioneers have had to beat out can unfortunately be followed but by the
few. It is not given to our science to strike the public mind at once with
the magnitude of its achievements, as is the case with the great works of
the engineer. Nevertheless the scientific skill which enables a Forth
Bridge to be constructed for the use of the travelling public of this
age--marvellous as it may appear to the uninstructed--is equalled, if not
surpassed, by the mastery of the intricate atomic groupings which has
enabled the chemist to build up the colouring-matters of the madder and
indigo plants.

A great industry needs no excuse for its existence provided that it
supplies something of use to man, and finds employment for many hands. The
coal-tar industry fulfils these conditions, as will be gathered from the
foregoing pages. If any further justification is required from a more
exalted standpoint than that of pure utilitarianism it can be supplied. It
is well known to all who have traced the results of applying any
scientific discovery to industrial purposes, that the practical
application invariably reacts upon the pure science to the lasting benefit
of both. In no department of applied science is this truth more forcibly
illustrated than in the branch of technology of which I have here
attempted to give a popular account. The pure theory of chemical
structure--the guiding spirit of the modern science--has been advanced
enormously by means of the materials supplied by and resulting from the
coal-tar industry. The fundamental notion of the structure of the benzene
molecule marks an epoch in the history of chemical theory of which the
importance cannot be too highly estimated. This idea occurred, as by
inspiration, to August Kekule of Bonn in the year 1865, and its
introduction has been marked by a quarter century of activity in research
such as the science of chemistry has never experienced at any previous
period of its history. The theory of the atomic structure of the benzene
molecule has been extended and applied to all analogous compounds, and it
is in coal-tar that we have the most prolific source of the compounds of
this