The second memorandum, which Nelson communicated to his fleet, soon after he joined it off Cadiz, is regarded by universal agreement as the high-water mark of sailing tactics.  Its interpretation however, and the dominant ideas that inspired it, no less than the degree to which it influenced the battle and was in the mind of Nelson and his officers at the time, are questions of considerable uncertainty.  Some of the most capable of his captains, as we shall see presently, even disagreed as to whether Trafalgar was fought under the memorandum at all.  From the method in which the attack was actually made, so different apparently from the method of the memorandum, some thought Nelson had cast it aside, while others saw that it still applied.  A careful consideration of all that was said and done at the time gives a fairly clear explanation of the divergence of opinion, and it will probably be agreed that those officers who had a real feeling for tactics saw that Nelson was making his attack on what were the essential principles of the memorandum, while some on the other hand who were possessed of less tactical insight did not distinguish between what was essential and what was accidental in Nelson’s great conception, and, mistaking the shadow for the substance, believed that he had abandoned his carefully prepared project.

For those who did not entirely grasp Nelson’s meaning there is much excuse.  We who are able to follow step by step the progress of tactical thought from the dawn of the sailing period can appreciate without much difficulty the radical revolution which he was setting on foot.  It was a revolution, as we can plainly see, that was tending to bring the long-drawn curve of tactical development round to the point at which the Elizabethans had started.  Surprise is sometimes expressed that, having once established the art of warfare under sail in broadside ships, our seamen were so long in finding the tactical system it demanded.  Should not the wonder be the converse:  that the Elizabethan seamen so quickly came so near the perfected method of the greatest master of the art?  The attack at Gravelines in 1588 with four mutually supporting squadrons in echelon bears strong elementary resemblance to that at Trafalgar in 1805.  It was in dexterity and precision of detail far more than in principle that the difference lay.  The first and the last great victory of the British navy had certainly more in common with each other than either had with Malaga or the First of June.  In the zenith of their careers Nelson and Drake came very near to joining hands.  Little wonder then if many of Nelson’s captains failed to fathom the full depth of his profound idea.  Naval officers in those days were left entirely without theoretical instruction on the higher lines of their profession, and Nelson, if we may judge by the style of his memoranda, can hardly have been a very lucid expositor.  He thought they all understood what with pardonable pride he called the ‘Nelson touch.’  The most sagacious and best educated of them probably did, but there were clearly some—­and Collingwood, as we shall see, was amongst them—­who only grasped some of the complex principles which were combined in his brilliant conception.