in an enemy’s harbours in order to render more effective a blockade was no novelty in maritime warfare, as Russell must have well known, and that there was no modern record of such obstructions having permanently destroyed a harbour.  A far more reasonable explanation is that which connects the energy of the British Government in opposing a proposed American closing of Southern harbours by Presidential proclamation, with a like energy against the stone boat project.  The first method was indeed rightly regarded as a violation of accustomed maritime belligerency, but both methods were primarily objectionable in British eyes because they were very evidently the result of efforts to find a way in which an as yet ineffective blockade could be made more rigorous.  On the impossibility of an effective blockade, if conducted on customary lines, the British people and Foreign Secretary had pinned their faith that there would be no serious interruption of trade.  This was still the view in January, 1862, though doubts were arising, and the “stone boat” protest must be regarded as another evidence of watchful guardianship of commerce with the South.  The very thought that the blockade might become effective, in which case all precedent would demand respect for it, possibly caused Russell to use a tone not customary with him in upbraiding the North for a planned “barbarity.”

Within three months the blockade and its effectiveness was to be made the subject of the first serious parliamentary discussion on the Civil War in America.  In another three months the Government began to feel a pressure from its associate in “joint attitude,” France, to examine again with much care its asserted policy of strict neutrality, and this because of the increased effectiveness of the blockade.  Meanwhile another “American question” was serving to cool somewhat British eagerness to go hand in hand with France.  For nearly forty years since independence from Spain the Mexican Republic had offered a thorny problem to European nations since it was difficult, in the face of the American Monroe Doctrine, to put sufficient pressure upon her for the satisfaction of the just claims of foreign creditors.  In 1860 measures were being prepared by France, Great Britain and Spain to act jointly in the matter of Mexican debts.  Commenting on these measures, President Buchanan in his annual message to Congress of December 3, 1860, had sounded a note of warning to Europe indicating that American principles would compel the use of force in aid of Mexico if debt-collecting efforts were made the excuse for a plan “to deprive our neighbouring Republic of portions of her territory.”  But this was at the moment of the break-up of the Union and attracted little attention in the United States.  For the same reason, no longer fearing an American block to these plans, the three European Governments, after their invitation to the United States to join them had been refused, signed a convention, October 31, 1861, to force a payment of debts by Mexico.  They pledged themselves, however, to seek no accession of territory and not to interfere in the internal affairs of Mexico.