In light Kundt's name is widely known for his inquiries in anomalous dispersion, not only in liquids and vapours, but even in metals, which he obtained in very thin films by means of a laborious process of electrolytic deposition upon platinized glass.
A third class of electric wave detector depends upon the power of electric oscillations to annul the electrolytic polarization of electrodes of small surface immersed in an electrolyte.
This increases the resistance of the electrolytic cell.
If, however, one electrode of this cell is connected to the earth and the other to a receiving antenna and electric waves allowed to fall on the antenna, the oscillations passing through the electrolytic cell will remove the polarization and L temporarily decrease the resistance of the cell.
Schloemilch 19 and others, and are known as electrolytic detectors.
The receiving arrangements comprised also an open or antenna circuit connected directly with a closed condenser-inductance circuit, but in place of the spark gap in the transmitter an electrolytic receiver was inserted, having in connexion with it as indicator a voltaic cell and telephone.
At the receiving station the differences in these systems depend chiefly upon variations in the actual form of the oscillation detector used, whether it be a loose contact or a thermal, electrolytic or magnetic detector.
Klaproth in 1799, is obtained when pure carbon (graphite or charcoal) is oxidized by alkaline permanganate, or when carbon forms the positive pole in an electrolytic cell (Ber., 1883, 16, p. 1209).
Wolcott Gibbs worked out the electrolytic separation of copper in 1865.
Quantitative methods are divided into four groups, which we now pass on to consider in the following sequence: (a) gravimetric, (0) volumetric, (7) electrolytic, (5) colorimetric.
(7) Electrolytic. - This method consists in decomposing a solution of a salt of the metal by the electric current and weighing the metal deposited at the cathode.
(5) Colorimetric. - This method is adopted when it is necessary to determine minute traces (as in the liquid obtained in the electrolytic separation of copper) of substances which afford well-defined colour reactions.
The first exact quantitative study of electrolytic phenomena was made about 1830 by Michael Faraday (Experimental Researches, 1833).
1) through two branches containing the two electrolytic cells A and B.
Kohlrausch formulated a theory of electrolytic conduction based on the idea that, under the action of the electric forces, the oppositely charged ions moved in opposite directions through the liquid, carrying their charges with them.
Again, water, the best electrolytic solvent known, is also the body of the highest specific inductive capacity (dielectric constant), and this property, to whatever cause it may be due, will reduce the forces between electric charges in the neighbourhood, and may therefore enable two ions to separate.
This view of the nature of electrolytic solutions at once explains many well-known phenomena.
An interesting relation appears when the electrolytic conductivity of solutions is compared with their chemical activity.
Moreover, a study of the chemical relations of electrolytes indicates that it is always the electrolytic ions that are concerned in their reactions.
Arrhenius has pointed out that the coefficient of affinity of an acid is proportional to its electrolytic ionization.
We may take it, then, that only that portion of these bodies is chemically active which is electrolytically active - that ionization is necessary for such chemical activity as we are dealing with here, just as it is necessary for electrolytic conductivity.
But the ions of an electrolytic solution can move independently through the liquid, even when no current flows, as the consequences of Ohm's law indicate.
C. Jones, The Theory of Electrolytic Dissociation (New York, 1900); N.
Some of the more important papers on the subject have been reprinted for Harper's Series of Scientific Memoirs in Electrolytic Conduction (1899) and the Modern Theory of Solution (1899).
The electrolytic reduction of the aromatic nitro compounds gives rise to substituted hydroxylamines which are immediately transformed into aminophenols or amines.
The earliest is that of Quincke, who coated a glass grating with a chemical silver deposit, subsequently thickened with copper in an electrolytic bath.
It is best to commence the electrolytic thickening in a silver acetate bath.
In the absence of metallic tin there is no visible change; but, as soon as the metal is introduced, an electrolytic action sets in and the articles get coated over with a firmly adhering film of tin.
Borchers, trace it to the presence of oxide, produced, for example, either by the use of a solution containing a trace of basic salt of zinc (to prevent which the bath should be kept just - almost imperceptibly - acid), or by the presence of a more electro-negative metal, which, being co-deposited, sets up local action at the expense of the zinc. Many processes have been patented, the ore being acted upon by acid, and the resulting solution treated, by either chemical or electrolytic means, for the successive removal of the other heavy metals.
30) obtained potassium by the electrolysis of a mixture of potassium and calcium chlorides fused over a lamp. There are here foreshadowed two types of electrolytic furnace-operations: (a) those in which external heating maintains the electrolyte in the fused condition, and (b) those in which a currentdensity is applied sufficiently high to develop the heat necessary to effect this object unaided.
In ordinary electrolytic work only the continuous current may of course be used, but in electrothermal work an alternating current is equally available.
It was found in practice (in 1889) that the expenditure of energy per pound of reduced aluminium was about 23 H.P.-hours, a number considerably in excess of that required at the present time for the production of pure aluminium by the electrolytic process described in the article Aluminium.
Since that date other processes have been devised and the electrolytic processes have entirely replaced the older methods of reduction with sodium.
Methods have also been discovered for the electrolytic manufacture of calcium, which have had the effect of converting a laboratory curiosity into a product of commercial importance.
The principle usually followed in the electrolytic refining of metals is to cast the impure metal into plates, which are exposed as anodes in a suitable solvent, commonly a salt of the metal under treatment.
Similarly, the formation of organic halogen products may be effected by electrolytic chlorine, as, for example, in the production of chloral by the gradual introduction of alcohol into an anode cell in which the electrolyte is a strong solution of potassium chloride.
Many electrolytic methods have been proposed for the purification of sugar; in some of them soluble anodes are used for a few minutes in weak alkaline solutions, so that the caustic alkali from the cathode reaction may precipitate chemically the hydroxide of the anode metal dissolved in the liquid, the precipitate carrying with it mechanically some of the impurities present, and thus clarifying the solution.
Peters has found that with these methods the best results are obtained when ozone is employed in addition to electrolytic oxygen.
(Leipzig, 1900); Gore, The Art of Electrolytic Separation of Metals (London, 1890); Blount, Practical Electro-Chemistry (London, 1906); G.
A group of bodies may, however, be yet discovered between alloys and electrolytes in which evidence may be found of some gradual change from wholly metallic to electrolytic conduction.
For electrolytic precipitation the solution may contain up to 0.1% KCN.
In the Transvaal the operation occupies 32 to 4 days for fine sands, and up to 14 days for coarse sands; the quantity of cyanide per ton of tailings varies from 0.26 to 0.28 lb, for electrolytic precipitation, and o 5 lb for zinc precipitation.
- The electrolytic separation of the gold from cyanide solutions was first practised in the Transvaal.
Many variations of the electrolytic process as above outlined have been suggested.
In the " dry " methods the silver is converted into sulphide or chloride, the gold remaining unaltered; in the " wet " methods the silver is dissolved by nitric acid or boiling sulphuric acid; and in the electrolytic processes advantage is taken of the fact that under certain current densities and other circumstances silver passes from an anode composed of a gold-silver alloy to the cathode more readily than gold.
Miller's chlorine process is of any importance, this method, and the wet process of refining by sulphuric acid, together with the electrolytic process, being the only ones now practised.
It is especially suitable to gold containing little silver and base metals - a character of Australian gold - but it yields to the sulphuric acid and electrolytic methods in point of economy.
The electrolytic parting of gold and silver has been shown to be more economical and free from the objections - such as the poisonous fumes - of the sulphuric acid process.
Von Riemsdijk) and 270.5° (C. C. Person); commercial bismuth melts at 260° (Ledebur), and electrolytic bismuth at 264° (Classen).
Electrolytic or ionic dissociation is the separation of a substance in solution into ions.
Whether continuous current or alternating current, and if the latter, whether monophase or polyphase; (ii) according to whether they record intermittently or continuously; (iii) according to the principle of their action, whether mechanical or electrolytic; (iv) according to the nature of the measurement, whether quantity or energy meters.
Most of the practical meters in use at the present time may be classified under the following five heads: electrolytic meters, motor meters, clock meters, intermittent registering meters and induction meters.
Electrolytic Meters are exclusively ampere-hour meters, measuring electric quantity directly and electric energy only indirectly, on the assumption that the pressure of the supply is constant.
The first electrolytic house meter in connexion with public electric supply was described by St.