'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]

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 wa