[Footnote 30: Nocturnal exploration of the College roofs has been so favourite an amusement amongst undergraduates that not long ago a book was actually published entitled _The Roof-Climber's Guide to Trinity College_. Every eminence in the College has been scaled, save only the Great Gate Tower. The Hon. C. S. Rolls, who was afterwards the first man to fly from England to France and back, and who fell a martyr to his zeal for aviation, was, in his day, the most daring and systematic of all Trinity roof-climbers.] [Footnote 31: Byron himself was morbidly sensitive on this point. Mr. Clark (_Guide to Cambridge_, p. 140) tells how he abused a friend who fell behind out of courtesy: "Ah! I see you wish to spy out my deformity." He was in residence 1805-8.] For these few will care; but this end of the library contains things which few can fail to care about. Here is the death-mask of Sir Isaac Newton, and a reflecting telescope, on the model invented by him. Here is Thackeray's manuscript of "Esmond," and Tennyson's manuscript of "In Memoriam." Here is Milton's manuscript of "Lycidas," and his first design for "Paradise Lost," all cut and scored about with alterations and corrections, showing that he originally designed his great poem to be a drama, the characters of which (headed by Moses) are here listed. Here, too, is a copy of the "Solemn League and Covenant" imposed on all men by the Puritans at the time of the Great Rebellion.[32] This was found hidden amongst the rafters of a village church near Cambridge. [Footnote 32: This instrument bound its subscribers to zealous endeavour, far from any "detestable indifference and neutrality," for the "extirpation of Popery, Prelacy, ... Archbishops, Bishops, Deans, Chapters, Archdeacons, and all that Hierarchy." Every adult in the kingdom had to sign this very thoroughgoing test, on pain of imprisonment.] And here is a copy of the famous Indulgence sold by Tetzel, Luther's denunciation of which gave the signal for the earliest outburst of Protestantism at the Reformation. When the crabbed old printing is deciphered it proves to be a startlingly mild document, no licence to commit sin, as is generally supposed, but merely granting to the purchaser the privilege of confessing, once in his life, to a priest of his own choice instead of to the parson in whose parish he dwelt. The priest so chosen is given authority to absolve from nearly all sins, but not from the heinous offence of buying alum from anyone except the Pope, in whose territory it had, at that date (1515), been recently discovered. Alum was in those days a most valuable substance, and had hitherto been attainable only at the Turkish town of Roc, in Syria, whence the name of "rock alum" still surviving in use amongst pharmacopoeists. To buy it there was not only to take money out of the pocket of the Pope, but to put it into those of the enemies of Christendom. Hence the heinousness of the offence.