Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

such a number of these were provided in connection, as to give him a battery of some two thousand pairs. It was with such ample means that Davy, and, still more recently, Faraday, made their splendid discoveries. Dr. Wollaston found that the effect of this battery was still further augmented in power, for the same number of cells, if there was a greater surface given to the copper than to the zinc. This double-sized copper characterized the Wollaston battery. Berzelius then demonstrated that if, instead of using a wooden trough, the copper itself be made into cells, or cups, so as to hold and en- velop the zincs, but without touching, this would enhance still further the excellency of the battery. Such galvanic arrangements were for many years exclusively used for all experiments and practice that was ventured upon ; but they all possessed one great in- Fig 9 ABer2eIiusBattery; convenience ; and that was, that after a very separate from the induction . , ,. ,. . , .. i n it Ilelix,— commonly called the short time they lost their power, and finally „Coiiper and Zillc„ or Bul. would cease to act, until they were cleaned p'mte of c°ppc'' Battery, and replenished. To avoid this, M. Becquerel proposed to plunge each of the metals into a special liquid, — being separated from each other by a porous diaphragm which would conduct and allow a com- munication between the two liquids. To that end he con- structed a battery in a glass jar ; he then placed in this vessel a cylinder of zinc, closed at its bottom like a deep cup. In the space between the glass jar and its contained zinc cylinder he placed the acidulated water ; but in the interior of the zinc was placed a bladder, or piece of intestine, which contained the copper, together with a strong solution of the sulphate of cop- per. When the poles of this battery are connected, both the water and the solution of sulphate of copper are decomposed by the electro-chemical action ; one part of the oxygen liberated combines with zinc to form oxide of zinc, which at once combines again with the sulphuric acid that acidulated the outer fluid to form sulphate of zinc, while another part of the oxygen com-