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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. 1913 edition. Excerpt:...does not mean that the copper is being dissolved by the acid; it does mean, however, that the hydrogen from the electrolyte is transferred during the operation of the cell from the solution to the positive electrode, upon which it forms a gaseous layer. This collection of H on the positive electrode reduces the E.M.F. of the cell (Supplement, 572), thereby cutting down the current. When in this condition the cell is said to be polarized. Polarization is the reduction of the E.M.F. of a cell due usually to the collection of hydrogen on the positive electrode. 314. Polarization, How Remedied. Polarization is detrimental because it reduces the E.M.F. of the cell. It may be remedied by adding to the electrolyte an oxidizing agent; that is, a substance which will furnish oxygen to unite chemically with the hydrogen on the electrode and thus form water, as represented by the chemical equation 2 H + O = H2O One of the most desirable oxidizing agents for depolarizing purposes is a solution of chromic acid. Next in importance is a solution of sodium bichromate. Potassium bichromate is sometimes used; it is not so satisfactory, however, as the sodium bichromate on account of the insoluble crystals which it forms. 315. Factors that Determine the E.M.F. of a Cell. The electromotive force of a cell is determined by three factors: (a) the kind of electrodes used, (b) the nature of the electrolyte, and (c) the temperature at which the cell operates. The E.M.F. is independent of the size of the plates. A cell of given materials, such for example as zinc, copper, and dilute sulphuric acid, no larger than a lady's thimble will furnish as high an E.M.F. as will a similar cell having a volume capacity of several gallons. While the E.M.F. of a cell is...