I may premise that Cambridge has an important advantage over Oxford in the fact that she has a far larger number of men to choose from in selecting a university crew. It may seem to many, at first sight, that as good a crew might well be selected from three hundred as from five hundred boating-men; because it is not to be supposed that either number would supply many more than eight first-rate oarsmen. But it must be remembered that there are first-rate oarsmen _and_ first-rate oarsmen. The unpractised eye may detect very little difference between the best and the worst oarsmen in such crews as Oxford and Cambridge yearly send to contend for the blue-riband of the river. But differences exist; and if the best man of the crew were replaced by one equal in rowing ability to the worst, or _vice versâ_, an important difference would be observed in the time of rowing over the racing course, under similar conditions of wind, tide, and so forth. Accordingly, a large field for the selection of the men is a most important advantage. Taking, for instance, the five hundred rowing men of Cambridge and dividing them into two sets--one of three hundred men, corresponding to the three hundred rowing men of Oxford, and the other of two hundred men--we see that the first set ought to supply a crew strong enough to meet Oxford, and the second a crew nearly as strong. Now, if the best men of the two Cambridge crews thus supposed to be formed are combined--say five taken from the first and three from the second, all the inferior men being struck out--a far stronger crew than either of the others would undoubtedly be formed. So that if Cambridge were generally the winner in these contests, the Oxonians would be able to account for their want of success in a sufficiently satisfactory manner. The successive defeats sustained by the Cambridge crews in 1861-69 are therefore so much the less readily explained as due to mere accident, by which of course I mean simply such an accidental circumstance as that better oarsmen chanced to be at Oxford than at Cambridge in these years, not to accident occurring in the race itself. Several reasons were assigned from time to time for the repeated victories of Oxford. Some of these may conveniently be examined here, before discussing what I take to be the true explanation.