The first of these often quoted memoranda is the ‘Plan of Attack,’ usually assigned to May 1805, when Nelson was in pursuit of Villeneuve, and it is generally accompanied by two erroneous diagrams based on the number of ships which he then had under his command.  But, as Professor Laughton has ingeniously conjectured, it must really belong to a time two years earlier, when Nelson was off Toulon in constant hope of the French coming out to engage him.[1] The strength and organisation of Nelson’s fleet at that time, as well as the numbers of the French fleet, exactly correspond to the data of the memorandum.  To Professor Laughton’s argument may be added another, which goes far actually to fix the date.  The principal signal which Nelson’s second method of attack required was ‘to engage to leeward.’  Now this signal as it stood in the Signal Book of 1799 was to some extent ambiguous.  It was No. 37, and the signification was ’to engage the enemy on their larboard side, or to leeward if by the wind,’ while No. 36 was ’to engage the enemy on their starboard side if going before the wind, or to windward if by the wind.’  Accordingly we find Nelson issuing a general order, with the object apparently of removing the ambiguity, and of rendering any confusion between starboard and larboard and leeward and windward impossible.  It is in Nelson’s order book, under date November 22, 1803, and runs as follows: 

’If a pennant is shown over signal No. 36, it signifies that ships are to engage on the enemy’s starboard side, whether going large or upon a wind.

’If a pennant is shown in like manner over No. 37, it signifies that ships are to engage on the enemy’s larboard side, whether going large or upon a wind.

’These additions to be noted in the Signal Book in pencil only.’[2]

The effect of this memorandum was, of course, that Nelson had it in his power to let every captain know, without a shadow of doubt, under all conditions of wind, on which side he meant to engage the enemy.

To the evidence of the Signal Book may be added a passage in Nelson’s letter to Admiral Sir A. Ball from the Magdalena Islands, November 7, 1803.  He there writes:  ’Our last two reconnoiterings:  Toulon has eight sail of the line apparently ready for sea ... a seventy-four repairing.  Whether they intend waiting for her I can’t tell, but I expect them every hour to put to sea.’[3] He was thus expecting to have to deal with eight or nine of the line, which is the precise contingency for which the memorandum provides.  There can be little doubt therefore that it was issued while Nelson lay at Magdalena, the first week in November 1803.[4]