_Defence of Venice by Von Ebner._--During this brief struggle, defensive torpedo operations were carried out under the direction of Colonel Von Ebner, of the Imperial Austrian Engineers. The harbour of Venice was protected by a most elaborate system of submarine mines, devised by the above-named officer. Though the importance of his system was proved by the fact of no attempt being made on Venice, yet no opportunity was afforded of _practically_ testing its efficiency. AMERICAN CIVIL WAR (1861-65). _Cause of the Present Importance of the Torpedo._--The prominent position the torpedo now holds as a most important and legitimate function of naval warfare is owing without doubt to the successful and extensive employment of them on the part of the Confederates during this long and bloody struggle. _Reasons which induced the Confederates to employ Torpedoes._--The numerous harbours and navigable rivers in the possession of the Southerners, the few ships of war at their disposal, the overwhelming fleet of the Northerners, and the introduction for the first time of ironclads in naval warfare, are the principal causes which forced the Confederates to resort to torpedoes as a means of offence and defence. Though a few rude and extempore submarine mechanical mines were met with by the Federals during the earliest part of the war, it was not until many months after the commencement of hostilities that the Confederates, finding themselves quite unable to cope with their rivals on the sea, set to work in earnest to organise a system of submarine warfare on a grand scale. _Torpedo Corps formed, &c.--Loss of "Cairo."_--By October, 1862, a secret service torpedo corps, with headquarters at Richmond, was in full swing, and the principal harbours and rivers of the Confederates were systematically protected by means of electrical and mechanical mines, also a scheme of offence by drifting and spar torpedoes was in preparation, and in December of the same year they experienced the first-fruits of their labour by the total destruction of the Federal war steamer _Cairo_. The following brief review of the numerous torpedo operations carried out by both sides, and the effect their use had on the war, will be sufficient to enable the general reader to gain some idea of the vast importance of this submarine weapon in future warfare. Fuller and more detailed accounts will be found in Commander S. Barnes's, U.S.N., Colonel Von Scheliha's, and Captain H. Steward's torpedo works.