experiments he was making at this time with friction fuses ended in an explosion, by which his hearing was permanently injured.
While Siemens was stationed, in 1840, at Wittenberg, he became interested in the discovery, then recently made by Jacobi, of the precipitation of metallic copper from the sulphate by means of the galvanic current. He repeated the experiments successfully, and applied the process-—so far as his means would permit—to other metals. His studies were interrupted by his arrest and imprisonment for connection as second with a duel between two of his brother-officers. Not relishing the idea of spending an indefinite period in idleness, he managed on his way to the citadel to make arrangements to have the materials required in his electroplating researches smuggled in to him. He set up a small laboratory in his cell and made himself contented there. Recollecting, from experiments he had made in the Daguerrean process, that hyposulphite of soda would dissolve the insoluble salts of gold and silver, he applied the principle to electrolysis with astonishing success; and he believes, he says, that it was one of the greatest joys of his life when a newly silvered teaspoon which he had immersed at the zinc pole of a Daniell cell into a cup filled with a hyposulphite gold solution, while the copper pole was connected with a louis d'or as an anode, "was converted in a few minutes into a gilded spoon of the most beautiful, purest golden luster." Galvano-plating was then new in Germany, and his discovery made much talk. A jeweler of Magdeburg, visiting him in prison to examine into its merits, he sold him the right to use it for forty louis, and thus obtained means for continuing his experiments. He counted upon enjoying still several months of captivity, and the unmolested prosecution of his researches, when the unwelcome message came to him of a royal pardon, and he was obliged to leave the citadel at once, without house or other spot in which to set up his apparatus. He asked leave from the commandant to stay a little longer, but was denied, accused of being ungrateful for the royal clemency, and was hurried out of his quarters at midnight. He had gained by his experimenting the reputation of not being well qualified for practical work, and was assigned to the fireworks factory at Spandau. He had great success in making pieces of unexampled brilliancy for the birthday celebration of the Emperor of Russia, and was invited to compete in a sailboat race with Prince Frederick Karl—and beat him. Then he was ordered to Berlin, to serve in the artillery arsenal; to his great delight—for this commission would give him time and opportunity for carrying on his researches.
Wilhelm Siemens having completed his studies and constructed a steam engine, Werner furnished it with a differential regulator. He made a profitable contract with a silver-ware