2 Voltaic Electricity and Electrolysis

    The discovery of so-called contact electricity by Galvani (1780) and Volta (1792) is so well known that we may pass by it here. However interesting Galvani's experiments..." "...and the resulting discussion about the origin of electric charges may be, we are here more concerned with formulating concepts  and laws. Hence we shall recount only the facts..."

Fig.81  Voltaic cell

    "...If two different metals are dipped into a solution (Fig. 81), say, copper and zinc into dilute sulphuric acid, the metals manifest electric charges that have exactly the same properties as frictional electricity. According to the fundamental law of electricity, charges of both signs occurr on the metals (poles) to the same amount. The system composed of the solution and the metals, which is called a voltaic element or cell, thus has the power of separating the two kinds of electricity. Now, it is remarkable that this power is apparently inexhaustible, for if the poles are connected by a wire so that their charges flow around and neutralize each other, as soon as the wire is  

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again removed, the poles are still charged. Thus the element continues to keep up the supply of electricity as long as the wire connection is maintained. Hence a continuous flow of electricity must be taking place. How this is to be imagined in detail depends on whether the one-fluid or the two-fluid theory is accepted. In the former case only one current is present: in the latter, two opposite currents, one of each fluid, flow.      Now, the electric current manifests its existence by showing very definite effects. Above all it heats the connecting wire. Everyone knows this fact from the metallic filaments in our electric bulbs. Thus the current continually produces hear energy. From what does the voltaic element derive the power of producing electricity con-tinually and thereby indirectly generating heat? According to the law of conservation of energy, wherever one kind of energy appears during a process, another kind of energy must disappear to the same extent.    
      The source of energy is the chemical process in the cell. One metal dissolves as long as the current flows; at the same time a constituent of the solution separates out on the other. Complicated chemical processes may take place in the solution itself. We have nothing to do with these but content ourselves with the fact that the voltaic element is a means of generating electricity in unlimited quantities and of producing considerable electric currents.
      We shall now have to consider, however, the reverse process, in which the electric current produces a chemical decomposition. For example, if we allow the current between two indecomposable wire leads (electrodes), say of platinum, to flow through slightly acidified water, the latter resolves into its components, hydrogen and oxygen, the hydrogen coming off at the negative electrode (cathode), the oxygen at the positive electrode (anode), The quantitative laws of this process of "electrolysis," discovered by Nicholson and Carlisle (1800) were found by Faraday (1832). The far-reaching conse-quences of Faraday's researches for the knowledge of the structure of matter are well known; it is not the consequences themselves that lead us to discuss these researches but the fact that Faraday's laws furnished the means of measuring electric currents accurately, and hence allowed the structure of electromagnetic theory to be com-pleted.  

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This experiment of electrolytic dissociation can be carried out not only with a voltaic current, but just as well with a discharge current, which occurs when oppositely charged metallic bodies are connected by a wire. Care must be taken that the quantities of electricity that are discharged are sufficiently great. We have appara-tus for storing electricity, so-called condensers , whose action depends on the induction principle, and which give such powerful discharges that measurable amounts are decomposed in the electrolytic cell. The amount of the charge that flows may be measured by the methods of electrostatics discussed above. Now Faraday discovered the law that twice the charge produces twice the dissocia-tion, three times the charge three times the dissociation - in short that the amount m of dissociated substance (or of one of the products of dissociation) is proportional to the quantity e of electricity that has passed through the cell:
Cm= e.
The constant C depends on the nature of the substances and of the chemical process.
    A second law of Faraday regulates this dependence. It is known that chemical elements combine in perfectly definite proportions to form compounds. The quantity of an element that combines with 1 gm. of the lightest element, hydrogen, is called its equivalent weight. For example, in water (H 2 O)
8gm. of oxygen (O) are combined with 1 gm. of hydrogen (H), hence oxygen has the equivalent weight 8gm. Now Faraday's law states that the same quantity of electricity that seperates out 1 gm. of hydrogen is able to separate out 1 gm. of hydrogen is able to separate out an equivalent weight of every other element, for example, 8 gm. of oxygen.
       Hence the constant C need only be known for hydrogen, and then we get it for every other substance by dividing this value by the equivalent weight for the substance."
The scribe noted the appearance of Ra and the eight.

Page 159

...Thus electrolytic dissociation furnishes us with a very convenient measurement of the quantity of electricity e
That has passed through the cell during a discharge. We need only determine the mass m of a product of decomposition that has the equivalent weight..." "...and then we get the desired quantity of electricity from equation (48). It is of course a matter of indifference whether this electricity is obtained from the discharge of charged conductors (condensers) or whether it comes from a voltaic cell. In the latter case the electricity flows continuously with constant strength; this means that the charge = J x t passes through any cross-section of the conducting circuit and hence also through the decomposing cell in the time t Here the quantity
is called the intensity of current or current strength, for it measures how much electrical charge flows through the cross-section of the conductor per unit time.
Page 160
       1 + 6 = 7

3. Resistance and Heat of Current

We must next consider the process of conduction or current itself. It has been customery to compare the electric current with the flowing of water in a pipe and to apply the concepts there valid to the electrical process. If water is to flow in a tube there must be some driving force If it flows from a higher vessel through an inclined tube to a lower vessel, gravitation is the driving force (Fig. 82 ) This is greater, the higher the upper surface of the water
Fig 82 The current strength of the water is proportional to the potential difference V and therefore to the difference h in height of the two levels.
is above the lower. But the velocity of the current of water, or its current strength, depends not only on the forces exerted by gravi-tation but also on the resistance that the water experiences in the conducting tube. If this is long and narrow, the amount of water passing through per unit of time is less than in the case of a short wide tube. The currant strength J is thus proportional to the difference V of potential energy that drives the water (which is proportional to the difference in height h of the two levels;"
"...and inversely proportional to the resistance W. We set  

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     J = V   or  JW =V,                                                                                                                                              (50)
In which the unit of resistance chosen is that which allows one unit of current to flow when the difference of level is one unit of height.
     G.S. Ohm (1826) applied precisely the same ideas to the electric current. The difference of level that effects the flow corresponds to the electric force. We define the sign of the current as positive in the direction from the positive to the negative pole. For a definite piece of wire of length l we must set V=El, where E is the field strength, which is regarded constant along the wire. For if the same electric field acts over a greater length of wire, it furnishes a ber impulse to the flowing electricity. The force V is also called the electromotive force (difference of potential or level) It is, moreover, identical with the concept of electric potential which we mentioned above (p.154).
     Since the current strength J and the electrical intensity of field E, hence also the potential difference or electromotive force V = El, are measurable quantities, the proportionality between J and V expressed in Ohm's may be tested experimentally
     The resistance W depends on the material and the form of the conducting wire; the longer and thinner it is the greater is W. If l is the length of the wire and f the size of the cross-section then W is directly proportional to l, and inversely proportional to f.

where the factor of proportionality..."  "...depends only on the material of the wire and is called the conductivity..."

Page 162  
    1 + 6 + 2 = 9

"... In this form Ohm's law is left only one constant whose value depends on the conducting material, namely, the conductivity, but in no other way depending on the form and size of the conducting body (wire).
    In the case of insulators..." "= 0. But ideal insulators do not exist. Very small traces of conductivity are always present except in a com-plete vacuum. There is an unbroken sequence leading from bad conductors (such as porcelain or amber) to the metals, which have enormously high conductivity.
      We have already pointed out that the current heats the conducting wire. The quantitative law of this phenomenon was found by Joule (1841). It is clearly a special case of the law of conservation of energy, in which electric energy becomes transformed into heat. Joule's law states that the heat developed per unit of time by the current J in traversing the potential difference V is
Q = JV,                                                                                                                                                                                  (53)  
Where Q is to be measured not in calories but in mechanical units of work. We shall make no further use of this formula, and state it here merely for the sake of completeness.

By this time both the Zed Aliz Zed and far yonder scribes's Z's, were about ready to abandon their gyroscopes

162  1 x 6 x 2 = 12  1 + 2 = 3   1 + 6 + 2 = 9





4 Electromagnetism

Up to the early nineteenth century, electricity and magnetism were regarded as two regions of phenomena which was similar in some respects but quite separate and independent. A bridge was eagerly sought between the two regions, but for a long time without success. At last Oersted (1820) discovered that the magnetic needle is deflected by voltaic currents. In the same year Biot and Savart discovered the quantitive law of this phenomenon, which Laplace formulated in terms of action at a distance. This law is very important for us, for the reason that in it there occurs a constant peculiar to electromagnetism and of the nature of a velocity, which showed itself later to be identical with the velocity of light.
    Biot and Savart established that the current flowing in a straight wire neither attracts nor repels a magnetic pole, but strives to drive  

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it around in a circle about the wire (Fig. 83), so that the positive pole moves in the sense of a right handed screw turned from below (con-trary to the hands of a watch) about the positive direction of the current."

That's odd said the odd ones, at odds over whether the watch was showing the right time, or had it now taken a turn for the hearse. To which the scribe responded would you believe, by writing the words Spirit and Spiral.

"The quantitative law can be brought into the simplest form by supposing the conducting wire to be divided into a number of short pieces of length l and writing down the effects of these current elements, from which the whole current is obtained by summation. We shall state the lae of a current element only for the special case in which the magnetic pole lies in the plane that passes through the middle part of the element and is perpendicular"

         Fig 83 The magnetic field H surrounding a current J.         Fig. 84 The direction of H is perpendicular to the directions
                                                                                                                    of J and the radius vector r  
"to its direction (Fig 84). Then the force that acts on the magnet pole of unit strength, i.e., the magnetic intensity of field H in this plane is perpendicular to the line connecting the pole with the mid-point of the current element, and is directly proportional to the current intensity J and to its lengthl, and inversely proportional to the square of the distance r:"

                                                                                                 cH= J1 .                                                                                  (54)

"Outwardly this formula has again a similarity to Newton' law of attraction or Coulomb's law of electrostatics and magnetostatics, but the electromagnetic force has nevertheless a totally different  

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character. For it does not act in the direction of the connecting line but perpendicular to it. The three directions J,r H are  perpendi-cular to each other in pairs. From this we see that electrodynamic effects are intimately connected with the structure of Euclidean space; in a certain sense they furnish us with a natural rectilinear coordinate system..."
     The factor of proportionality c introduced in formula (
54) is com-pletely determined since the distance r, the current strength J and the magnetic field H are measurable quantities. It clearly denotes the strength of that current which, flowing through a peiece of conducter of unit length, produces a unit of magnetic field at a unit distance. It is customary and often convenient to choose in place of the unit of current that we have introduced (namely, the quantity of static electricity that flows through the cross-section per unit of time and is called the electrostatic unit), this current of strength c (in electrostatic measure) as the unit of current; it is then called the electromagnetic unit of current. Its use has an advantage in that
                                                                       Jl           Hr2 ,
Equation (54) assumes the simple form  H= r2 or J =  l       so that measurement of the strength of a current is reduced to that of two lengths and of a magnetic field. Most practical instruments for measuring currents depend on the deflection of magnets by currents, or the converse, and hence give the current strength in electro-magnetic measure.
To express this in terms of the electrostatic measure of current first introduced the constant c must be known; for this, however, only one measurement is necessary.
     Before we speak of the experimental determination of the quantity c, we shall get an insight into its nature by means of a simple dimen-sional consideration. According to (54) it is defined by c = J l .
                                                                                                               Hr 2
Page 165

"But we know that the electric charge e and the magnetic strength of pole p have the same dimensions because Coulomb's law for electric and magnetic force is exactly the same. Hence..."
"...c has the dimensions of a velocity.
   The first exact measurement of c was carried out by Weber and Kohlrausch (1856). These experiments belong to the most memor-able achievements of precise physical measurement not only on account of their difficulty but also on account of the far-reaching consequences of the result. For the value obtained for c was
3 x 10 10  cm. / sec., which is exactly the velocity of light.
      This equality could not be accidental. Numerous thinkers, including Weber himself and many other mathematicians and phy-sicists, felt the close relationship that the number c =
3 x 10  10 cm./sec established between two great realms of science, and they sought to discover the bridge that ought to connect electromagnetism and optics. This was accomplished by Maxwell after Faraday's wonder-ful and ingenious method of experimenting had brought to light new facts and new views..."

This has arrived said Zed Aliz, its for inclusion afore even the even deadline.

The Expanding Universe
Sir Arthur Eddington 1932

Page 113

                           "...and since the velocity of light c is 300,000 km per sec.,..."
9th line down of main text.
Writ the scribe, counting on it

Cassell's English Dictionary 1974

Page 69

"Augean (aw je an ) [L. Augeas, Gr. Augeias], a.Pertaining to Augeas (mythic king of Elis, whose stable, containing 3000 oxen, had not been cleaned

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out for thirty years, till Hercules, by turning the river Alpheus through it, did so in a day) ;..."
 At this most critical moment in the now of our passing. The Zed AlizZed took time out to address yon companies goodly mix of striven souls. And in manner gentle, this incantation sold .Dearest of dear friends, all iz one and one iz all, the GOD of the THAT, iz the GOD of MIND, THAT MIND hath always sparkling point with thee.THAT mind of thine, and THAT sparkle point of the THAT, iz the number
NINE,and its dynastic progeny. NINE iz the number of the THAT. Listen to the call of thy GOD      
                                                                   '3000 Oxen  x   thirty years'
                                                                               ' thirty years'
                                                                                     30 x 360                                                                                                  10800
                                                                             Ra + the eight gods