of war with Spain. While the tension lasted he is known
to have used the critical period in exercising his fleet in tactical
evolutions, in order to perfect it in a new code of signals which he
had been elaborating for several years.[1] It is probable therefore
that this Signal Book belongs to that year, and that it is one of
several copies which Howe had printed with the battle signals blank
for his own use while he was elaborating his system by practical
experiment. This conjecture is brought to practical certainty by a
rough and much-worn copy of it in the United Service Institution. It
was made by Lieut. John Walsh, of H.M.S. Marlborough, one of Howe's
fleet, and inside the cover he has written 'Earl Howe's signals by
which the Grand Fleet was governed 1790, 1791, and 1794.'

It was upon the tactical system contained in this book that all the
great actions of the Nelson period were fought. The alterations which
took place during the war were slight. The codes used by Howe himself
in 1794, and by Duncan at Camperdown in 1797, follow it exactly. A
slightly modified form was issued by Jervis to the Mediterranean
fleet, and was used by him at St. Vincent in 1797. No copy of this is
known to exist, but from the logs of the ships there engaged it would
appear that, though the numbering of the code had been changed, the
principal battle signals remained the same. In 1799 a new edition was
printed in the small quarto form. In this the Signal Book and the
Instructions were bound together, and were issued to the whole navy,
but here again, though the numbers were changed, the alterations were
of no great importance.[2] Reprints appeared in 1806 and 1808, but
the code itself continued in use till 1816. In that year an entirely
new Signal Book based on Sir Home Popham's code was issued with a
fresh set of Explanatory Instructions, or, as they had come to be
called, 'Instructions relating to the line of battle and the conduct
of the fleet preparatory to their engaging and when engaged with an
enemy.'[3] Both these sets of 'Explanatory Instructions' are printed
below, but, as we have seen, they throw but little light by themselves
on the progress of tactical thought during the great period they
covered. They were no longer 'Fighting Instructions' in the old sense,
unless read with the principal battle signals, and to these we have to
go to get at the ideas that underlay the tactics of Nelson and his
contemporaries.

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