An effective steam postal marine is unquestionably most desirable and necessary for the defense of our country, and for the prosecution of any foreign war. Lord Canning, the British Post-Master General, recently said in a report to the House of Lords, that although all of the steam mail packets might not be able to carry an armament, or be required in the transport service in time of war, yet the mail facilities which they would then afford would be more important and necessary than at any other time. He had no idea that because engaged in a foreign war the postal service would be useless, but to the contrary, more than ever indispensable. Such proved to be the fact in the late contest in the Crimea, and such is to-day the case with regard to the troubles in India and China. Their postal vessels have proven a first necessity in both of these wars, not only for transport of the troops, but for speedy intelligence also. Without them, England could not have entered the Crimean contest, and the French forces would have been compelled to remain at home. Turkey would have been overawed, and Constantinople would have fallen before the Russian fleet. We are to-day, and always must be, liable to a foreign war. We have a great boiling cauldron running over with excitement all along our southern and south-western borders. Central America, Cuba, the West-Indies, and South-America are far more foreign countries to us than Europe or the Mediterranean to England. Cuba will no doubt be at some day our most important naval station and possession. Even the defense of our own coast would require an immense transport service; for Texas is nearly four thousand miles from Maine, and California is seven thousand from the Atlantic seaboard. No better proof can be given of the necessity of a large and extra naval transport service than the late Mexican war. But for our steamers it would have taken us years to concentrate an army on the shores of Mexico. It was a tedious process at the time; for our ocean mail packets were not then in use. We could now land a larger number of men there in one month than we then did in a whole year. But our transport facilities are not yet by any means adequate.