When the war commenced, there was a man named Maury, a lieutenant in the United States service, and who was connected with the National Observatory in Washington. He was thought to be a scientific, practical man. He had been educated by the government, had received great pay, and was in a high position; but he forgot all that, and joined the Rebels. He imitated General Floyd, and stole public property, carrying off from the National Observatory valuable scientific papers which did not belong to him. He was employed by the Rebel government to construct torpedoes and infernal machines for blowing up Commodore Foote's gunboats. He had several thousand made,--some for the land, which were planted around Columbus in rear of the town, and which were connected with a galvanic battery by a telegraph wire, to be exploded at the right moment, by which he hoped to destroy thousands of the Union troops. He sunk several hundred in the river opposite Columbus. They were oblong cylinders of wrought iron, four or five feet in length; inside were two or three hundred pounds of powder. Two small anchors held the cylinder in its proper place. It was air tight, and therefore floated in the water. At the upper end there was a projecting iron rod, which was connected with a percussion gun-lock. If anything struck the rod with much force, it would trip the lock, and explode the powder. At least, Mr. Maury thought so. The above engraving will show the construction of the torpedoes, and how they were placed in the water. The letter A represents the iron rod reaching up almost to the surface of the water. At B it is connected with the lock, which is inside the cylinder, and not represented. C represents the powder. The arrows show the direction of the current. One day he tried an experiment. He sunk a torpedo, and let loose a flat-boat, which came down with the current and struck the iron rod. The powder exploded and sent the flat high into the air. Thousands of Rebel soldiers stood on the bluffs and saw it. They hurrahed and swung their hats. Mr. Maury was so well pleased that the river was planted with them, above, in front, and below the town. He thought that Commodore Foote and all his gunboats would be blown out of the water if they attempted to descend the stream. But the workmanship was rude. The parts were not put together with much skill. Mr. Maury showed that his science was not practical. He forgot that the river was constantly rising and falling, that sometimes the water would be so high the gunboats could glide over the iron rods with several feet between, he forgot that the powder would gather moisture and the locks become rusty. It was discovered, after a while, that the torpedoes leaked, that the powder became damp, and changed to an inky mass, and that the hundreds of thousands of dollars which Mr. Maury had spent was all wasted. Then they who had supposed him to be a scientific man said he was a humbug.