intendment) from February 9, 1863, to the 1st of May, time of the removal of Mr. Waldron from his office, Lieutenant Young having been appointed by General Ripley to take his place.

On the 9th of February last I reported to Major Harris for duty, and was assigned to Mr. Waldron as assistant engineer, recommended by Dr. Cheves. Mr. Waldron was left in charge of a line of electric torpedoes intended to obstruct the channel between Forts Moultrie and Sumter. The main portion of said cable was composed of a copper wire, insulated by a wrapper of cloth immersed in a solution of melted India rubber and protected by a double twist of cotton. To said line, 3,500 feet long, was attached twenty-five double branches, 90 feet in length and 100 feet apart, to be connected with fifty torpedoes, intended to be kept in a steady position through the means of a proper anchorage and at a certain depth (2 feet) below the surface of low water. During the contemplated attack upon the forts an electric current was to be ke permanent on thaw hole system, giving a sensitive property to each torpedo, the armatures spreading from the cartridge box having to be touched by the enemy's vessels in order to close the protecting distance between the poles, create the spark, and explode the fuse. Each branch (fifty in number) had to receive a special contrivance to secure the current within the line after the shooting of one or several torpedoes; but this arrangement was postponed by Dr. Cheves, for an elastic Indian-rubber tube was necessary for it, and could not be obtained in the limits of the Confederacy.

After a close examination of said line I concluded that the cable was not fit for use, for the main portion, which had to rest on the bottom (said bottom being, according to the map, a mixture of sand, broken stones, and shell), would have been worn and cut in a short time under the action of the tide. The accompanying specimen, A, is a portion of the same. the branches constructed in a similar way, but protected only by single wrapper, would be partly exposed to the same danger, and destroyed in a still shorter time. Specimen B is a piece of the same.

I accordingly reported the facts to Mr. Waldron, urging a complete change of the cable. In the mean of it was substituted to the main line and the former used for the branches, converting therefor the whole cable in a much stronger and substantial work, affording better chance to resist destruction. At the same time the torpedoes were tested and found incapable to resist the hydraulic pressure, for they all collapsed in 8 feet of water. They were made of tin-iron, without any frame inside, and altogether too light. I took as a substitute some small lager beer barrels of thirteen gallons' capacity. One of them was sunk in 24 feet water, and when taken up, twenty-four hours after, the inside was perfectly dry. Satisfied with their resistance, we had them cooperid properly, securing at each end a small wooden cone, in order to diminish the effect of the current. Inside and outside they were coated with a mixture of coal-tar and resin, of a suitable consistency. In these new torpedoes the same cartridge cones were used, the change being only in the difference of shape and material, the principle remaining exactly the same as previously established by Dr. Cheves. An elastic India-rubber tube of a certain diameter was absolutely necessary to complete the line. This article existing not in the limits of the Confederacy, Mr. Waldron applied to General Ripley for a lieutenant who had some experience in the India-rubber manufacture. After fifteen days of trails and experiments, resulting in very imperfect samples, the lieutenant abandoned the work. I then undertook the same, and succeeded at last in making