Cavendish, of Lavoisier, of Davy, of Lamarck, of Cuvier, of Jussieu,
of Decandolle, of Werner and of Hutton, suffices to indicate the
strength of physical science in the age immediately preceding that of
which I have to treat. But of which of these great men can it be said
that their labors were directed to practical ends? I do not call to
mind even an invention of practical utility which we owe to any of
them, except the safety lamp of Davy. Werner certainly paid attention
to mining, and I have not forgotten James Watt. But, though some of
the most important of the improvements by which Watt converted the
steam-engine, invented long before his time, into the obedient slave
of man, were suggested and guided by his acquaintance with scientific
principles, his skill as a practical mechanician, and the efficiency
of Bolton's workmen had quite as much to do with the realisation of
his projects.

[Sidenote: but instigated by love of knowledge]

In fact, the history of physical science teaches (and we cannot too
carefully take the lesson to heart) that the practical advantages,
attainable through its agency, never have been, and never will be,
sufficiently attractive to men inspired by the inborn genius of the
interpreter of nature, to give them courage to undergo the toils and
make the sacrifices which that calling requires from its votaries.
That which stirs their pulses is the love of knowledge and the joy of
the discovery of the causes of things sung by the old poets--the
supreme delight of extending the realm of law and order ever farther
towards the unattainable goals of the infinitely great and the
infinitely small, between which our little race of life is run. In the
course of this work, the physical philosopher, sometimes
intentionally, much more often unintentionally, lights upon something