The task to which Bacon had been set by the Papal mandate was rapidly accomplished, in spite of difficulties which might have overcome a less resolute spirit; but the work extended to such great length in his hands, that he seems to have felt a not unnatural fear that Clement, burdened with the innumerable cares of the Pontificate, would not find leisure for its perusal, much less for the study which some part of it demanded.  With this fear, fearful also that portions of his work might be deficient in clearness, and dreading lest it might be lost on its way to Rome, he proceeded to compose a second treatise, called the “Opus Minus,” to serve as an abstract and specimen of his greater work, and to embrace some additions to its matter.  Unfortunately, but a fragment of this second work has been preserved, and this fragment is for the first time published in the volume just issued under the direction of the Master of the Rolls.  But the “Opus Minus” was scarcely completed before he undertook a third work, to serve as an introduction and preamble to both the preceding.  This has been handed down to us complete, and this, too, is for the first time printed in the volume before us.  We take the account of it given by Professor Brewer, the editor, in his introduction.

“Inferior to its predecessors in the importance of its scientific details and the illustration it supplies of Bacon’s philosophy, it is more interesting than either, for the insight it affords of his labors, and of the numerous obstacles he had to contend with in the execution of his work.  The first twenty chapters detail various anecdotes of Bacon’s personal history, his opinions on the state of education, the impediments thrown in his way by the ignorance, the prejudices, the contempt, the carelessness, the indifference of his contemporaries.  From the twentieth chapter to the close of the volume he pursues the thread of the Opus Majus, supplying what he had there omitted, correcting and explaining what had been less clearly or correctly expressed in that or in the Opus Minus.  In Chapter LII. he apologizes for diverging from the strict line he had originally marked out, by inserting in the ten preceding chapters his opinions on three abstruse subjects, Vacuum, Motion, and Space, mainly in regard to their spiritual significance.  ‘As these questions,’ he says,’ are very perplexing and difficult, I thought I would record what I had to say about them in some one of my works.  In the Opus Majus and Opus Minus I had not studied them sufficiently to prevail on myself to commit my thoughts about them to writing; and I was glad to omit them, owing to the length of those works, and because I was much hurried in their composition.’  From the fifty-second chapter to the close of the volume he adheres to his subject without further digression, but with so much vigor of thought and freshness of observations, that, like the Opus Minus, the Opus Tertium may be fairly considered an independent work.”—­pp. xliv-xlv.[13]

The details which Bacon gives of his personal history are of special interest as throwing light upon the habits of life of a scholar in the thirteenth century.  Their autobiographic charm is increased by their novelty, for they give a view of ways of life of which but few particulars have been handed down.