He also promoted the study of mathematics, hitherto of little moment in the College. He founded a Philosophical Society, as a sort of offshoot of the Royal Society of London, to which he contributed a learned paper on Musical Sounds. The curious collection of ancient music still extant in his Library (bequeathed for the use of the City of Dublin, but mainly intended for a Diocesan Library) shows that he had a special interest in this subject. He wrote for the students a sensible text-book of Logic (_see fac-simile of title-page, p. 37_). He got a new and larger Chapel built, which lasted till 1798. But he was still in the era when the College authorities had no idea of building ornamentally. The houses and halls were merely modest constructions for use, and Dr. Campbell is quoted as describing them:-- The Chapel is as mean a structure as you can conceive; destitute of monumental decoration within; it is no better than a Welsh Church without. The old Hall, where College exercises are performed, is in the same range, and built in the same style.--_Op. cit._ p. 117. This is, I think, to be said of all the buildings in Dublin during the seventeenth century. So far as I know, the earliest, and perhaps the best attempt at artistic architecture is the Library, which was not commenced till 1709.[53] All the handsome houses in Dublin date from after the middle of the eighteenth century. [Illustration: FAC-SIMILE OF TITLE-PAGE, ARCHBISHOP MARSH’S “LOGIC.” Institutiones LOGICÆ. IN USUM JUVENTUTIS ACADEMICÆ DUBLINIENSIS. DUBLINI, Apud S. HELSHAM ad _Insignia Collegii_, in vico vulgò dicto _Castle-street_. 1681.]