Scientific American Supplement No. 819, September 12, 1891 eBook

This eBook from the Gutenberg Project consists of approximately 130 pages of information about Scientific American Supplement No. 819, September 12, 1891.

Scientific American Supplement No. 819, September 12, 1891 eBook

This eBook from the Gutenberg Project consists of approximately 130 pages of information about Scientific American Supplement No. 819, September 12, 1891.

Only fifteen years ago it would have been folly to desire to obtain remunerative results through the electrolysis of water.  Such research was subordinated to the industrial production of electric energy.

We shall not endeavor to establish the priority of the experiments and discoveries.  The question was in the air, and was taken up almost simultaneously by three able experimenters—­a Russian physicist, Prof.  Latchinof, of St. Petersburg, Dr. D’Arsonval, the learned professor of the College of France, and Commandant Renard, director of the military establishment of aerostation at Chalais.  Mr. D’Arsonval collected oxygen for experiments in physiology, while Commandant Renard naturally directed his attention to the production of pure hydrogen.  The solutions of the question are, in fact, alike in principle, and yet they have been developed in a very different manner, and we believe that Commandant Renard’s process is the completest from an industrial standpoint.  We shall give an account of it from a communication made by this eminent military engineer, some time ago, to the French Society of Physics.

Transformations of the Voltameter.—­In a laboratory, it is of no consequence whether a liter of hydrogen costs a centime or a franc.  So long as it is a question of a few liters, one may, at his ease, waste his energy and employ costly substances.

The internal resistance of a voltameter and the cost of platinum electrodes of a few grammes should not arrest the physicist in an experiment; but, in a production on a large scale, it is necessary to decrease the resistance of the liquid column to as great a degree as possible—­that is to say, to increase its section and diminish its thickness.  The first condition leads to a suppression of the platinum, and the second necessitates the use of new principles in the construction of the voltameter.  A laboratory voltameter consists either of a U-shaped tube or of a trough in which the electrodes are covered by bell glasses (Fig. 1, A and B).  In either case, the electric current must follow a tortuous and narrow path, in order to pass from one electrode to the other, while, if the electrodes be left entirely free in the bath, the gases, rising in a spreading form, will mix at a certain height.  It is necessary to separate them by a partition (Fig. 1, C).  If this is isolating and impermeable, there will be no interest in raising the electrodes sensibly above its lower edge.  Now, the nearer together the electrodes are, the more it is necessary to lower the partition.  The extension of the electrodes and the bringing of them together is the knotty part of the question.  This will be shown by a very simple calculation.

[Illustration:  Fig. 1.—­A, B, commonest forms of laboratory voltameters.  C, diagram showing ascent of bubbles in A voltameter.]

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Scientific American Supplement No. 819, September 12, 1891 from Project Gutenberg. Public domain.