Publisher's Synopsis
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 edition. Excerpt: ...a depolarizer, oxidizing the hydrogen to water and itself being reduced to nitrous gases. The electromotive force of this battery is between 1.6 and 1.7 volts. The Bunsen cell is a Grove cell with carbon in place of platinum for the positive pole. In the chromic acid battery, due to Poggendorff, the electrolyte is a solution of sulphuric acid and potassium bichromate. The positive pole is carbon and the negative zinc, which is withdrawn from the battery when not in use. The chromic acid acts as depolarizer. The electromotive force is about 1.3 volts. These batteries have at present little more than historical interest. The use of primary cells is now nearly entirely confined to the Leclanche, the Lalande, and the Daniell cells. Leclanche' brought out his cell in 1868.2 It consists of a zinc rod forming the negative pole and dipping into a solution of ammonium chloride. The positive pole is carbon in contact with manganese dioxide for a depolarizer. When the circuit is closed, zinc goes in solution as zinc chloride and the ammonium radical is deposited on the carbon, which breaks up into ammonia and hydrogen. The ammonia dissolves and the hydrogen is oxidized by the manganese dioxide to water. This depolarization is not rapid, however, consequently not much current can be taken from a Leclanche cell at a time without the voltage dropping considerably, but it recovers on standing. The electromotive force of this cell on open circuit differs from one cell to another, varying from 1.05 to 1.8 volts. This cell is put on the market under a large number of different 1 Wiedemann, Die Lehre von der Elektricitat, 1, 867, (1893). 2 Wiedemann, I.e. p. 850. forms and under different names. One of the best Leclanche cells on the market is the Sampson...