"The defeat of the British fleet or fleets would, of course, be effected by purely naval operations; but the acquiescence in its destruction could, perhaps, only be secured by a blow affecting the British power at its source, and therefore the establishment by an enemy of his naval superiority would almost certainly be followed by an invasion of Great Britain. So long, then, as the British navy can be maintained invincible, the Empire could be adequately defended against attack of any European Power other than Russia, and for such a defence, therefore, no more is needed than complete naval preparation, and such military preparation as is required for the full efficiency of the navy. Any additional military preparation is, as against attack of this nature, merely an insurance to cover the possibility of the failure of the navy. After such failure, it might save the British Islands, but it could not save the Empire."

Dilke wrote that this doctrine was the opposite of what he had previously held and preached, and expressed a doubt whether, that being the case, the book could go on as a joint work. Wilkinson replied that the first question was whether the doctrine of the chapter was sound, and that the question of the names on the title-page could wait till the work was done.

In Problems of Greater Britain Dilke had discussed the view of Sir John Colomb and of his brother, Admiral Colomb. The Admiral appeared to rely upon "blockade," which required a navy much stronger than Great Britain possessed, and might, with modern weapons and the torpedo, be impracticable of execution, while Sir John Colomb appeared to admit the necessity of purely military forces to prevent invasion. Dilke, looking at the extent of the Empire to be defended, had thought that the concentration of the navy in home waters must involve the abandonment of the rest of the Empire. This is the view usually held by those who are thinking of what they have to protect. Wilkinson thought first of the enemy's forces and how to destroy them. If they can be destroyed, the enemy is helpless and the territories of the victor are safe, because the enemy has no force with which to molest them. On the appearance of Problems, Dilke, as the extracts from his Diary at that time show, had begun to doubt whether this view was not the right one; Wilkinson's exposition and the discussion which accompanied it completed his conversion. This was the turning-point of his studies of Imperial Defence.

The next chapter was headed "The Command of the Sea." Here the debated doctrine was applied.

"The purpose of Great Britain to render her territories secure would be perfectly accomplished by the destruction of the enemy's navy, as this would render any attempt at the transport of troops impracticable. The destruction of the enemy's navy would, of course, also be the best possible protection for England's sea-borne trade (though, no doubt, for this purpose additional measures would be required), and for her communications with every part of her Empire. Thus, in every possible war in which Great Britain could engage, the prime function of the British navy is to attack, and if possible to destroy, the organized naval forces of the enemy."

Suppose the enemy sought battle, the question would soon be decided, but if he wished to avoid it the difficulty would be to find him and to compel him to accept it. For this purpose the best plan was that adopted in 1803 by Lord St. Vincent, which consisted in placing at the outset, in front of every one of the enemy's military ports, a British squadron superior to that which the enemy had within it. This was incorrectly termed "blockade," as the object was not to prevent the issue of the French fleets from their ports, but to prevent their exit unwatched and to fight them when they should come out. This plan must be supplemented by a reserve fleet, and by numerous cruisers to hunt such of the enemy's cruisers as might be at large. The alternative plan of Lord Howe, of concentrating the fleet at one of the home ports, was also discussed, but considered less advantageous, as it left the enemy's fleet free to proceed to sea. But it was shown that the navy of 1891 was twenty battleships short of the number believed by naval officers to be required for the successful adoption of St. Vincent's plan against the French navy alone.

The defence of India was treated in two chapters entitled "The Peace of India" and "The North-West Frontier," which were in substance a restatement of the view expressed in Problems of Greater Britain.

The chapter on "The Armies" was a translation into specific shape, with full details and calculations, of Dilke's idea of a separation between the British and Indian systems. It was argued that the militia and volunteers should be organized into army corps with permanent fully paid commanders and the necessary auxiliary troops, and it was pointed out that the volunteer department of the War Office ought to be entrusted to volunteer officers. A chapter on "The Management of the Home Army" asserted that "Any system proposed for the better management of the army must satisfy three distinct conditions: It must be framed with a view to the preparation of the army for war; it must secure unimpaired the authority of the Cabinet; and it must provide for an efficient control over expenditure by the House of Commons." The first requirement of a sound system was a general who could be entrusted with the duty of advising the Cabinet upon the conduct of war and with the actual management of campaigns. He ought to have a proper general staff and the field troops at home should be organized into localized autonomous army corps. "The British army at home has no generals, and can have none until its battalions are settled and grouped into brigades, divisions, and army corps." There must be a second general charged with all branches of supply.

Any satisfactory Admiralty system, it was pointed out, would provide a competent naval adviser for the Cabinet. But it was doubted "whether it will be possible to secure unity of design in defence so long as the War Office and the Admiralty are separately represented in the Cabinet. The difficulty would be overcome if it became the practice for one Minister to hold both offices." Dilke had long had the common-sense idea that a single Minister ought to have general charge of all the preparations for war and its conduct by sea and land.

He had made excisions and additions in the chapters as they had reached him, and had closely scrutinized the expression throughout. The whole book was read through by the two men together, and each point discussed to complete agreement. Dilke then proposed that it should appear in Wilkinson's name, as it was substantially Wilkinson's work, and that he himself might write a preface. Wilkinison said that it was a joint work, that the idea of the book was Dilke's, that its substance was the outcome of the intimate exchange of views between them, and that it ought to bear both their names. In his diary Dilke wrote: "Wilkinson's part in it was far greater than mine, though we argued out the whole." When the book appeared, Admiral Colomb wrote to Dilke: "On reading the introduction and the first and second chapters, I am inclined to sing 'Nunc dimittis,' for, as far as I can understand the matter, you put forward all the views for which I have contended; and coming thus from your hands, I think they will henceforth be current views." Dilke sent the letter to Wilkinson, noting on it: "Colomb thinks he has converted me. I reply, he couldn't. You did—after he had failed." He regarded his collaboration with Wilkinson as an intellectual partnership in regard to defence, and hardly ever spoke or wrote on the subject without referring to it.