to the United States at the earliest opportunity, and he accordingly declined the offer. In July, 1866 representatives from Sweden and Norway, and Holland came to London to be instructed. There is some evidence that Russia and England also sent representatives at this time. “I have a school under weigh”, humorously wrote Maury, “with Sweden and Norway as pupils—board and tuition 500 pounds. They will graduate in ‘sea mining’ this week. Monday the 16th, the school opens for the Dutch at 500 pounds. I have heard no more about turning Frenchman. But the King of Wurttemberg has been pestering me to keep the Prussians out of his pea-patch of a kingdom. ‘Barkis is willing’, but I can’t say whether anything will come out of it; I think not as the war looks like it is drawing to a close”. The lectures which Maury gave in connection with the demonstrations of his mines gave an introductory sketch of all that his predecessors since the time of Priestly had done in this field, an account of all that had been accomplished by the South with this new weapon during the late war, and then in detail the results of his own experiments. As far as the submarine mine was concerned, he added nothing new to what he had set down in the agreement with Holmes which was drawn up by him just before leaving England near the close of the war. But as to their use on land, the following details appear for the first time among his papers: “After this hasty sketch, I come to electrical torpedoes for guarding mountain passes and roadways, etc., for the protection of strongholds and the defense of fortified positions. Shells cast for the purpose should be used, but in an emergency tin canisters, or any other perfectly water-tight cases, will answer. I am not aware that electricity was used by either of the belligerents in the late American war for springing mines on land. “The cases for land-torpedoes should be shells cast expressly for the purpose. The thickness of the shell being from one-fourth to an inch, and even more, or less, according to the size and the probable handling in transportation.