therefore, form part of the
_Compendium_, as Brewer seems to think. It must be confessed, however, that
nothing can well be more confusing than the references in Bacon's works,
and it seems well-nigh hopeless to attempt a complete arrangement of them
until the texts have been collated and carefully printed.

All these large works Bacon appears to have looked on as preliminaries,
introductions, leading to a great work which should embrace the principles
of all the sciences. This great work, which is perhaps the
frequently-referred-to _Liber Sex Scientiarum_, he began, and a few
fragments still indicate its outline. First appears to have come the
treatise now called _Compendium Studii Philosophiae_ (Brewer pp. 393-519),
containing an account of the causes of error, and then entering at length
upon grammar. After that, apparently, logic was to be treated; then,
possibly, mathematics and physics; then speculative alchemy and
experimental science. It is, however, very difficult, in the present state
of our knowledge of the MSS., to hazard even conjectures as to the contents
and nature of this last and most comprehensive work.

Bacon's fame in popular estimation has always rested on his mechanical
discoveries. Careful research has shown that very little can with accuracy
be ascribed to him. He certainly describes a method of constructing a
telescope, but not so as to lead one to conclude that he was in possession
of that instrument. Burning-glasses were in common use, and spectacles it
does not appear he made, although he was probably acquainted with the
principle of their construction. His wonderful predictions (in the _De
Secretis_) must be taken _cum grano salis_; he believed in astrology, in
the doctrine of signatures, and in the philosopher's stone, and _knew_ that
the circle had been squared. For his work in connexion with gunpowder, the
invention of which has been claimed for him on the ground of a passage in
his _De mirabili potestate artis et naturae_, see GUNPOWDER.

_Summary._--The 13th century, an age peculiarly rich in great men, produced
few, if any, who can take higher rank than Roger Bacon. He is in every way
worthy to be placed beside Albertus Magnus, Bonaventura, and Thomas
Aquinas. These had an infinitely wider renown in their day, but modern
criticism has restored the balance in his favour, and is even in danger of
erring in the opposite direction. Bacon, it is now said, was not
appreciated by his age bec