The works appear to have been well received. We next find BACON at Oxford writing his _Compendium Studii Philosophiae_, in which work he indulged in some by no means unjust criticisms of the clergy, for which he fell under the condemnation of his order, and was imprisoned in 1277 on a charge of teaching "suspected novelties". In those days any knowledge of natural phenomena beyond that of the quasi-science of the times was regarded as magic, and no doubt some of ROGER BACON'S "suspected novelties" were of this nature; his recognition of the value of the writings of non-Christian moralists was, no doubt, another "suspected novelty". Appeals for his release directed to the Pope proved fruitless, being frustrated by JEROME D'ASCOLI, General of the Franciscan Order, who shortly afterwards succeeded to the Holy See under the title of NICHOLAS IV. The latter died in 1292, whereupon RAYMOND GAUFREDI, who had been elected General of the Franciscan Order, and who, it is thought, was well disposed towards BACON, because of certain alchemical secrets the latter had revealed to him, ordered his release. BACON returned to Oxford, where he wrote his last work, the _Compendium Studii Theologiae_. He died either in this year or in 1294.
 For further details concerning BACON'S life, EMILE CHARLES: _Roger Bacon, sa Vie, ses Ouvrages, ses Doctrines_ (1861); J. H. BRIDGES: _The Life & Work of Roger Bacon, an Introduction to the Opus Majus_ (edited by H. G. JONES, 1914); and Mr A. G. LITTLE'S essay in _Roger Bacon Essays_, may be consulted.
It was not until the publication by Dr SAMUEL JEBB, in 1733, of the greater part of BACON'S _Opus Majus_, nearly four and a half centuries after his death, that anything like his rightful position in the history of philosophy began to be assigned to him. But let his spirit be no longer troubled, if it were ever troubled by neglect or slander, for the world, and first and foremost his own country, has paid him due honour. His septcentenary was duly celebrated in 1914 at his _alma mater_, Oxford, his statue has there been raised as a memorial to his greatness, and savants have meted out praise to him in no grudging tones. Indeed, a voice has here and there been heard depreciating his better-known namesake FRANCIS, so that the later luminary should not, standing in the way, obscure the light of the earlier; though, for my part, I would suggest that one need not be so one-eyed as to fail to see both lights at once.
 See _Roger Bacon, Essays contributed by various Writers on the Occasion of the Commemoration of the Seventh Centenary of his Birth_. Collected and edited by A. G. LITTLE (1914); also Sir J. E. SANDYS' _Roger Bacon_ (from _The Proceedings of the British Association_, vol. vi., 1914).
 For example, that of ERNST DUHRING. See an article entitled "The Two Bacons," translated from his _Kritische Geschichte der Philosophie_ in _The Open Court_ for August 1914.
To those who like to observe coincidences, it may be of interest that the septcentenary of the discoverer of gunpowder should have coincided with the outbreak of the greatest war under which the world has yet groaned, even though gunpowder is no longer employed as a military propellant.
BACON'S reference to gunpowder occurs in his _Epistola de Secretis Operibus Artis et Naturae, et de Nullitate Magiae_ (Hamburg, 1618) a little tract written against magic, in which he endeavours to show, and succeeds very well in the first eight chapters, that Nature and art can perform far more extraordinary feats than are claimed by the workers in the black art. The last three chapters are written in an alchemical jargon of which even one versed in the symbolic language of alchemy can make no sense. They are evidently cryptogramic, and probably deal with the preparation and purification of saltpetre, which had only recently been discovered as a distinct body. In chapter xi. there is reference to an explosive body, which can only be gunpowder; by means of it, says BACON, you may, "if you know the trick, produce a bright flash and a thundering noise." He mentions two of the ingredients, saltpetre and sulphur, but conceals the third (_i.e_. charcoal) under an anagram. Claims have, indeed, been put forth for the Greek, Arab, Hindu, and Chinese origins of gunpowder, but a close examination of the original ancient accounts purporting to contain references to gunpowder, shows that only incendiary and not explosive bodies are really dealt with. But whilst ROGER BACON knew of the explosive property of a mixture in right proportions of sulphur, charcoal, and pure saltpetre (which he no doubt accidentally hit upon whilst experimenting with the last-named body), he was unaware of its projective power. That discovery, so detrimental to the happiness of man ever since, was, in all probability, due to BERTHOLD SCHWARZ about 1330.
 For an attempted explanation of this cryptogram, and evidence that BACON was the discoverer of gunpowder, see Lieut.-Col. H. W. L. HIME'S _Gunpowder and Ammunition: their Origin and Progress_ (1904).