preaching among the masses of the poor.  He had written little.  So far was he from attempting to write that his new superiors prohibited him from publishing anything under pain of forfeiture of the book and penance of bread and water.  But we can see the craving of his mind, the passionate instinct of creation which marks the man of genius, in the joy with which he seized a strange opportunity that suddenly opened before him.  “Some few chapters on different subjects, written at the entreaty of friends,” seem to have got abroad, and were brought by one of the Pope’s chaplains under the notice of Clement the Fourth.  The Pope at once invited Bacon to write.  But difficulties stood in his way.  Materials, transcription, and other expenses for such a work as he projected would cost at least, L60, and the Pope sent not a penny.  Bacon begged help from his family, but they were ruined like himself.  No one would lend to a mendicant friar, and when his friends raised the money he needed it was by pawning their goods in the hope of repayment from Clement.  Nor was this all; the work itself, abstruse and scientific as was its subject, had to be treated in a clear and popular form to gain the Papal ear.  But difficulties which would have crushed another man only roused Roger Bacon to an almost superhuman energy.  By the close of 1267 the work was done.  The “greater work,” itself in modern form a closely-printed folio, with its successive summaries and appendices in the “lesser” and the “third” works (which make a good octavo more), were produced and forwarded to the Pope within fifteen months.

[Sidenote:  The Opus Majus]

No trace of this fiery haste remains in the book itself.  The “Opus Majus” is alike wonderful in plan and detail.  Bacon’s main purpose, in the words of Dr. Whewell, is “to urge the necessity of a reform in the mode of philosophizing, to set forth the reasons why knowledge had not made a greater progress, to draw back attention to sources of knowledge which had been unwisely neglected, to discover other sources which were yet wholly unknown, and to animate men to the undertaking by a prospect of the vast advantages which it offered.”  The developement of his scheme is on the largest scale; he gathers together the whole knowledge of his time on every branch of science which it possessed, and as he passes them in review he suggests improvements in nearly all.  His labours, both here and in his after works, in the field of grammar and philology, his perseverance in insisting on the necessity of correct texts, of an accurate knowledge of languages, of an exact interpretation, are hardly less remarkable than his scientific investigations.  From grammar he passes to mathematics, from mathematics to experimental philosophy.  Under the name of mathematics indeed was included all the physical science of the time.  “The neglect of it for nearly thirty or forty years,” pleads Bacon passionately, “hath nearly destroyed the entire studies of