The number of things which Roger Bacon succeeded in discovering by the application of the principle of testing everything by personal observation, is almost incredible to a modern student of science and of education who has known nothing before of the progress in science made by this wonderful man. He has been sometimes declared to be the discoverer of gunpowder, but this is a mistake since it was known 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 than 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 known about gunpowder at this time, this was of itself a marvelous anticipation of what might be accomplished by it. [Illustration] RATHHAUS (TANGERMÜNDE) Bacon prophesied, however, much more than merely {43} 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 concluded 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 realized 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." [Footnote 5] When we recall that the very latest thing in transportation are motor-boats and automobiles driven by gasoline, a high explosive, Roger Bacon's prophesy becomes one of these weird anticipations of human progress which seem almost more than human. [Footnote 5: These quotations are taken from Ozanam's Dante and Catholic Philosophy, published by the Cathedral Library Association, New York, 1897. ]