Spragge's 'Sea Book' contains also a set of ten 'additional instructions' all of which are new.

They are undated, but from another copy in Capt.

Robert Moulton's 'Sea Book' we can fix them to April 18th, 1665.[3] Their whole tenour suggests that they were the outcome of prolonged discussions in the council of war; and in the variously dated copies which exist of sections of the orders we have evidence that between the last week in March, when the duke hoisted his flag, and April 21st, when he put to sea, much time must have been spent upon the consideration of the tactical problem.[4] The result was a marked advance.

In these ten 'additional instructions,' for instance, we have for the first time a clear distinction drawn between attacks from windward and attacks from leeward.

We have also the first appearance of the close-hauled line ahead, and it is enjoined as a defensive formation when the enemy attacks from windward.