Such, then, is the fundamental principle of the memorandum as enunciated in its opening paragraphs. He then proceeds to elaborate it in two detailed plans of attack—one from to-leeward and the other from to-windward. It was the latter he meant to make if possible. He calls it 'the intended attack,' and it accords with the opening enunciation. The organisation is triple, but no special function is assigned to the reserve squadron. The actual attack on the enemy's rear is to be made by Collingwood, while Nelson with his own division and the reserve is to cover him. In the event of an attack having to be made from to-leeward, the idea is different. Here the containing movement practically disappears. The fleet is still to attack the rear and part of the centre of the enemy, but now in three independent divisions simultaneously, in such a way as to cut his line at three points, and to concentrate a superior force on each section of the severed line. To none of the divisions is assigned the duty of containing the rest of the enemy's fleet from the outset. It is to be dealt with at a second stage of the action by all ships that are still capable of renewing the engagement after the first stage. 'The whole impression,' as Nelson put it, in case he was forced to attack from to-leeward, was to overpower the enemy's line from a little ahead of the centre to the rearmost ship. He does not say, however, that this was to be 'the whole impression' of the intended attack from to-windward. 'The whole impression' there appears to be for Collingwood to overpower the rear while Nelson with the other two divisions made play with the enemy's van and centre; but the particular manner in which he would carry out this part of the design is left undetermined.

The important point, then, in considering the relation between the actual battle and the memorandum, is to remember that it provided for two different methods of attacking the rear according to whether the enemy were encountered to windward or to leeward. The somewhat illogical arrangement of the memorandum tends to conceal this highly important distinction. For Nelson interpolates between his explanation of the windward attack and his opening enunciation of principle his explanation of the leeward attack, to which the enunciation did not apply. That some confusion was caused in the minds of some even of his best officers is certain, but let them speak for themselves.

After the battle Captain Harvey, of the Téméraire, whom Nelson had intended to lead his line, wrote to his wife, 'It was noon before the action commenced, which was done according to the instructions given us by Lord Nelson…. Lord Nelson had given me leave to lead and break through the line about the fourteenth ship,' i.e. two or three ships ahead of the centre, as explained in the memorandum for the leeward attack but not for the windward.

On the other hand we have Captain Moorsom, of the Revenge, who was in Collingwood's division, saying exactly the opposite. Writing to his father on December 4, he says, 'I have seen several plans of the action, but none to answer my ideas of it. A regular plan was laid down by Lord Nelson some time before the action but not acted on. His great anxiety seemed to be to get to leeward of them lest they should make off to Cadiz before he could get near them.' And on November 1, to the same correspondent he had written, 'I am not certain that our mode of attack was the best: however, it succeeded.' Here then we have two of Nelson's most able captains entirely disagreeing as to whether or not the attack was carried out in accordance with any plan which Nelson laid down.

Captain Moorsom's view may be further followed in a tactical study written by his son, Vice-Admiral Constantine Moorsom.[20] His remarks on Trafalgar were presumably largely inspired by his father, who lived till 1835. In his view there was 'an entire alteration both of the scientific principle and of the tactical movements,' both of which he thinks were due to what he calls the morale of the enemy's attitude—that is, that Nelson was afraid they were going to slip through his fingers into Cadiz. The change of plan—meaning presumably the change from the triple to the dual organisation—he thinks was not due to the reduced numbers which Nelson actually had under his flag, for the ratio between the two fleets remained much about the same as that of his hypothesis.

The interesting testimony of Lieutenant G.L. Browne, who, as Admiral Jackson informs us, was assistant flag-lieutenant in the Victory and had every means of knowing, endorses the view of the Moorsoms.[21] After explaining to his parents the delay caused by the established method of forming the fleets in two parallel lines so that each had an opposite number, as set forth in the opening words of the memorandum, he says, 'but by his lordship's mode of attack you will clearly perceive not an instant of time could be lost. The frequent communications he had with his admirals and captains put them in possession of all his plans, so that his mode of attack was well known to every officer of the fleet. Some will not fail to attribute rashness to the conduct of Lord Nelson. But he well considered the importance of a decisive naval victory at this time, and has frequently said since we left England that, should he be so fortunate as to fall in with the enemy, a total defeat should be the result on the one side or the other.'

Next we have what is probably the most acute and illuminating criticism of the battle that exists, from the pen of 'an officer who was present.' Sir Charles Ekin quotes it anonymously; but from internal evidence there is little difficulty in assigning it to an officer of the Conqueror, though clearly not her captain, Israel Pellew, in whose justification the concluding part was written. Whoever he was the writer thoroughly appreciated and understood the tactical basis of Nelson's plan, as laid down in the memorandum, and he frankly condemns his chief for having exposed his fleet unnecessarily by permitting himself to be hurried out of delivering his attack in line abreast as he intended. It might well have been done, so far as he could see, without any more loss of time than actually occurred in getting the bulk of the fleet into action. Loss of time was the only excuse for attacking in line ahead, and the only reason he could suppose for the change of plan. If they had all gone down together in line abreast, he is sure the victory would have been more quickly decided and the brunt of the fight more equally borne. Nothing, he thinks, could have been better than the plan of the memorandum if it had only been properly executed. An attack in two great divisions with a squadron of observation—so he summarises the 'Nelson touch'—seemed to him to combine every precaution under all circumstances. It allows of concentration and containing. Each ship can use her full speed without fear of being isolated. The fastest ships will break through the line first, and they are just those which from their speed in passing are liable to the least damage, while having passed through, they cause a diversion for the attack of their slower comrades. Finally, if the enemy tries to make off and avoid action, the fleet is well collected for a general chase. But as Nelson actually made the attack in his hurry to close, he threw away most of these advantages, and against an enemy of equal spirit each ship must have been crushed as she came into action. Instead of doubling ourselves, he says, we were doubled and even trebled on. Nelson in fact presented the enemy's fleet with precisely the position which the memorandum aimed at securing for ourselves—that is to say, he suffered a portion of his fleet, comprising the Victory, Téméraire, Royal Sovereign, Belleisle, Mars, Colossus, and Bellerophon, to be cut off and doubled on.[22]

The last important witness is Captain Codrington, of the Orion. No one seems to have kept his head so well in the action, and this fact, coupled with the high reputation he subsequently acquired, gives peculiar weight to his testimony. It is on the question of the advanced or reserve squadron that he is specially interesting. On October 19 at 8 P.M., just after they had been surprised and rejoiced by Nelson's signal for a general chase, and were steering for the enemy, as he says, 'under every stitch of sail we can set,' he sat down to write to his wife. In the course of the letter he tells her, 'Defence and Agamemnon are upon the look out nearest to Cadiz; … Colossus and Mars are stationed next. The above four and as many more of us are now to form an advanced squadron; and I trust by the morning we shall all be united and in sight of the enemy.' Clearly then Nelson must have issued some modification of the dual 'order of battle and sailing.' Many years later in a note upon the battle which Codrington dictated to his daughter, Lady Bourchier, he says that on the 20th, in spite of Collingwood's advice to attack at once, Nelson 'continued waiting upon them in two columns according to the order of sailing and the memorable written instruction which was given out to all the captains.'[23] Later still, when a veteran of seventy-six years, he gave to Sir Harris Nicolas another note which shows how in his own mind he reconciled the apparent discrepancy between the dual and the triple organisation. It runs as follows: 'In Lord Nelson's memorandum of October 9, 1805, he refers to "an advanced squadron of eight of the fastest sailing two-decked ships" to be added to either of the two lines of the order of sailing as may be required; and says that this advanced squadron would probably have to cut through "two, three or four ships of the enemy's centre so as to ensure getting at their commander-in-chief, on whom every effort must be made to capture";[24] and he afterwards twice speaks of the enemy's van coming to succour their rear. Now I am under the impression that I was expressly instructed by Lord Nelson (referring to the probability of the enemy's van coming down upon us), being in the Orion, one of the eight ships named, that he himself would probably make a feint of attacking their van in order to prevent or retard it.' Here then would seem to be still further confusion, due to a failure to distinguish between the leeward and windward form of attack. According to this statement Codrington believed the advanced squadron was in either case to attack the centre, while Nelson with his division contained the van. But curiously enough in a similar note, printed by Lady Bourchier on Nicolas's authority, there is a difference in the wording which, though difficult to account for, seems to give the truer version of what Codrington really said. It is there stated that Codrington told Nicolas he was strongly impressed with the belief 'that Lord Nelson directed eight of the smaller and handier ships, of which the Orion was one, to be ready to haul out of the line in case the enemy's van should appear to go down to the assistance of the ships engaged to meet and resist them: that to prevent this manoeuvre on the part of the enemy Lord Nelson intimated his intention of making a feint of hauling out towards their van,' &c. There is little doubt that we have here the true distribution of duties which Nelson intended for the windward attack—that is, the advanced squadron was to be the real containing force, but he intended to assist it by himself making a feint on the enemy's van before delivering his true attack on the centre.[25]

From Codrington's evidence it is at any rate clear that some time before the 19th Nelson had told off an 'advanced squadron' as provided for in his memorandum, and that the ships that were forming the connection between the fleet and the frigates before Cadiz formed part of it. Now Nelson had begun to tell off these ships as early as the 4th. On that day he wrote to Captain Duff, of the Mars, 'I have to desire you will keep with the Mars, Defence and Colossus from three to four leagues between the fleet and Cadiz in order that I may get information from the frigates stationed off that port as expeditiously as possible.' On the 11th, writing to Sir Alexander Ball at Malta, he speaks of having 'an advanced squadron of fast sailing ships between me and the frigates.' The Agamemnon (64) was added on the 14th, the day after she joined. On that day Nelson entered in his private diary, 'Placed Defence and Agamemnon from seven to ten leagues west of Cadiz, and Mars and Colossus four leagues east of the fleet,' &c,[26] On the 15th he wrote to Captain Hope, of the Defence: 'You will with the Agamemnon take station west from Cadiz from seven to ten leagues, by which means if the enemy should move I hope to have constant information, as two or three ships will be kept as at present between the fleet and your two ships.'[27]

On the 12th he writes to Collingwood, of the Belleisle, the fastest two-decker in the fleet, as though she too were an advanced ship, and on the morning of the 19th he tells him the Leviathan was to relieve the Defence, whose water had got low. Later in the day, when Mars and Colossus had passed on the signal that the enemy was out, he ordered 'Mars, Orion, Belleisle, Leviathan, Bellerophon and Polyphemus to go ahead during the night.'[28] On the eve of the battle therefore these six ships, with Colossus and Agamemnon, made up the squadron of eight specified on the memorandum.