He first discovers the principles of classification in the printed book; then turning to the manuscripts--and there are at least nineteen in the Cambridge University Library, over all of which he has cast his eye,--reports that no two manuscripts are alike, but that "gradually by comparing many manuscripts we may be able to form some notion of the order in which and the times at which the various writs became recognised members of the _Corpus Brevium_." Tests are then laid down by which the age of a Register may be determined, and finally we have "a few remarks about the early history of the Register" which are entirely original and of high importance. The two earliest manuscripts are examined, the MS Register of 1227 in the British Museum with its fifty-six writs, the MS Cambridge Register belonging likewise to the early part of Henry III's reign with its fifty-eight writs; and means are thus supplied for measuring the growth of law during the important period--the period of the Great Charter--which had elapsed between Glanvill's treatise and the third decade of the thirteenth century. Then we are guided through the later and more voluminous manuscripts. We are introduced to a Register with one hundred and twenty-one writs from the middle of the thirteenth century, to an Edwardian Register which contains four hundred and seventy-one writs; we see the writ of trespass taking a permanent place in the _Corpus Brevium_ under Edward II, we trace activity under Edward III and Richard II and then a slackening. By the turn of the fourteenth century the "great cathedral" is practically complete and the Register has assumed a form not substantially different from that which was printed in the reign of Henry VIII.