In 1844 some attention was attracted to an alleged invention of a Captain Warner for blowing up ships. The _John of Gaunt_, a sailing-ship, was taken in tow by a steamer and blown up off Brighton in the presence of an immense crowd of spectators; but as the inventor wanted the Admiralty to pay him £400,000 for it before he showed them what it was like, his secret naturally remained a secret. It would seem to have been merely a mine floating just beneath the surface of the water, with some arrangement to explode it on contact. The Crimean War gave us some little experience of underwater mines, for several were employed by the Russians in the Baltic and the Black Sea. They were feeble affairs, and did no damage worth mentioning. One was fished up and exploded on board one of our ships, but no one was seriously hurt. Some were made of copper, others of wood fastened together like the staves of a barrel. But the rumour of these mines, which were stated to contain 700 pounds of powder and to explode either on contact or by what was then called a "galvanic current"--that is to say, electricity--caused the allied French and British fleets in the Baltic to exercise great care in their movements. As at the present day, a system of trawling for them was instituted, and no less than fifty were picked up off Cronstadt in ten days. [Illustration: Russian Mine laid in the Baltic in the Crimean War A B, Close-fitting copper cases containing powder. C, Leather tube containing electric wire. D, Mooring weight. E, Small white wooden ball showing position of mine. F, Openings to load mine. G, Iron framework supporting mine. K, Iron ring-part of frame. L, Mooring rope.] "The angling for this dangerous kind of prey was thus managed: two boats took between them a long rope, which was sunk by heavy weights to a depth of ten or twelve feet, and held suspended at that depth by empty casks as floats; the boats then separated as far as the rope would allow, and rowed onwards at right angles to the length of the rope; it was a species of trawl fishing in which the agitation of the floats showed that a prey had been caught, which prey was then hauled up carefully."[55] Mines were also fished up off Kertch and other Black Sea ports, showing that the Russians had gone in extensively for submarine defence, and only failed in causing us serious loss on account of the primitive character of the mines and the precautions which we took against them. On our part we had some idea of using a so-called submarine invented by Mr. Scott Russell, a noted engineer; but it seems to have been merely an elongated diving-bell which could not carry out a satisfactory trial. Two attempts were made by Boatswain John Shepherd, R.N., to blow up Russian ships in the harbour of Sebastopol, but apparently without success. He went in alone in a punt, taking with him some kind of an explosive apparatus, and for his "bold and gallantly executed" exploits he received the Victoria Cross.