wn many years before by the Arabs
and by them introduced into Europe. He did study explosives very
deeply, however, and besides learning many things about them,
realized how much might be accomplished by their use in the
after-time. He declares in his Opus Magnum: "That one may cause to
burst forth from bronze, thunderbolts more formidable that those
produced by nature. A small quantity of prepared matter occasions a
terrible explosion accompanied by a brilliant light. One may
multiply this phenomenon so far as to destroy a city or an army."
Considering how little was know about gunpowder at this time, this
was of itself a marvelous anticipation of what might be accomplished
by it.

Bacon anticipated, however, much more than merely destructive
effects from the use of high explosives, and indeed it is almost
amusing to see how closely he anticipated some of the most modern
usages of high explosives for motor purposes. He seems to have
realized that some time the apparently uncontrollable forces of
explosion would come under the control of man and be harnessed by
him for his own purposes. He foresaw that one of the great
applications of such a force would be for transportation.
Accordingly he said: "Art can construct instruments of navigation
such that the largest vessels, governed by a single man, will
traverse rivers and seas more rapidly than if they were filled with
oarsmen. One may also make carriages which without the aid of any
animal will run with remarkable swiftness." {323} When we recall
that the very latest thing in transportation are motor-boats and
automobiles driven by gasoline, a high explosive, Roger Bacon's
prophecy becomes one of those weird anticipations of human progress
which seem almost more than human.

It was not with regard to explosives alone, however, that Roger
Bacon was to make great advances and still more marvelous
anticipations in physical science. He was not, as is sometimes
claimed for him, either the inventor of the telescope or of the
theory of lenses. He did more, however, than perhaps anyone else to
make the principles of lenses clear and to establish them on a
mathematical basis. His traditional connection with the telescope
can probably be traced to the fact that he was very much interested
in astronomy and the relations of the heavens to the earth. He
pointed out very clearly the errors which had crept