9 
Sir Wrti1am R, Hamitron read a paper ‘‘On some General Theo- 
rems in the Calculus of Definite Integrals.’ 
MONDAY, JANUARY 25, 1858. 
James H. Topp, D.D., President, in the Chair. 
Tue Rev. Wioi11am Reeves, D.D., read a paper ‘‘ On the Cathach of 
Columcille’”’ (deposited in the Museum of the Academy by Sir Richard 
O’ Donnell, Bart.) 
Joun Kets Incram, LL. D., read a paper— 
ON THE OPUS MAJUS OF ROGER BACON. 
Arter some introductory observations on the unjust neglect with which 
the writings of Roger Bacon have hitherto been treated, the author pro- 
ceeded as follows :— 
In the course of my studies I have been able to clear up one unset- 
tled question respecting the works of this eminent man; and I have 
thought it probable that the Academy would be interested by any con- 
tribution, however small, towards our knowledge of a subject so imper- 
- fectly understood. 
The ‘‘ Opus Majus’” has always been regarded as the most impor- 
tant of Bacon’s writings. It was written in the year 1267, and sent to 
Pope Clement IV. in consequence of the desire expressed by that Pontiff 
that Bacon would communicate to him the substance of his researches. 
A beautiful MS. of the work exists in the Library of Trinity College, 
Dublin, and from this MS. it was edited by Samuel Jebb, at London, in 
1733. It is to this edition, or to the reprint of it at Venice, in 1750, 
that all the historians of philosophy have referred. The work, as pub- 
lished by Jebb, contains six parts, the subjects of which are as follows:— 
In the first Bacon points out the four universal causes of human igno- 
rance; in the second he treats of the relation of philosophy to theology; 
in the third, of grammar and the knowledge of languages; in the fourth, 
of mathematics, including astronomy and geography; in the fifth, of 
perspectiva, or optics; and in the sixth, of experimental science. 
When Bacon had composed the ‘‘ Opus Majus,”’ he drew up a second 
treatise, similar in substance, which he called his “‘ Opus Minus,” and 
which he also transmitted to the Pope. His object in doing so was partly 
to guard against the risk of the ‘‘Opus Majus’’ being lost, from the dan- 
gers which then beset travellers, and partly to present to his Holiness, 
in a condensed and improved form, its most essential contents. Not 
satisfied with this precaution, he prepared a third version of his great 
work, which he named his ‘‘ Opus Tertium,” ‘ad intellectum et per- 
fectionem utriusque operis precedentis,”’ and this also he transmitted to 
Clement. The two latter works have never been printed, but several 
copies of, at least, portions of them exist in the manuscript collections 
of Great Britain and continental Europe. 
