Bringing Modern Views of Electricity into the Digital Age
I’ve been working on digitizing Modern Views of Electricity by Sir Oliver Lodge, a book that takes a deep look at early ideas about electricity, energy flow, and inertia. The goal is to make it more accessible and readable for modern audiences, fixing spelling mistakes, cleaning up messy math, and structuring it better.
This isn’t just about preservation—it’s about making Lodge’s ideas easier to explore in today’s AI-driven world. The way we study historical scientific texts is changing, and I want this book to be part of that shift.
Did Electricity Have Inertia? Early Scientists Thought So
One of the most interesting parts of the book is Lodge’s discussion on inertia in electricity. Back then, some scientists thought that electric current might behave like a moving fluid, meaning it would take time to start or stop, just like water in a pipe. If that were true, we should see signs of momentum when switching currents on and off.
Scientists, including Clerk Maxwell, looked for this effect by testing whether an electrical coil with a current would behave like a gyroscope, resisting movement. But nothing like that was ever found—electricity doesn’t seem to have mechanical inertia.
That said, Lodge points out that there is still something like inertia in electrical circuits. When a circuit is broken suddenly, a spark appears because the current doesn’t stop instantly—it “bursts through” the gap with energy. These effects, once called extra-currents, are now explained by self-induction and electromagnetic fields.
Poynting’s Discovery: Energy Doesn’t Travel Inside Wires
Another big shift in thinking came from John Henry Poynting, who showed that electrical energy doesn’t actually flow through wires at all—it moves through the space around them.
Before Poynting’s work, most people assumed that electricity traveled through conductors like water through a pipe. But in reality, the electric and magnetic fields around the wire are what guide energy. The wire is just there to provide the structure—the real action is happening in the surrounding space.
This was a huge change in how scientists thought about electricity. It helped move away from the idea of electricity as a physical substance and towards what we now understand as electromagnetic fields and waves.
Why Digitize This Book?
Lodge’s work captures a time when scientists were still figuring out the basics of electromagnetism. Some of the ideas turned out to be wrong, others became the foundation of modern electrical engineering. But either way, these early discussions still matter.
By digitizing this book, I want to:
- Make it easier to read and explore, especially for people who aren’t used to old-style scientific writing.
- Fix messy math and formatting, so the equations make sense.
- Preserve the original ideas, while making them clearer for today’s researchers and students.
There’s something exciting about looking at these old debates with fresh eyes. With today’s technology—AI, simulations, and advanced electromagnetic research—we can re-examine these ideas in ways Lodge and his peers never could.
What’s Next?
I’m planning to keep working through Modern Views of Electricity, cleaning up more sections and making them available in a format that works for modern research and education. If you’re interested in historical electromagnetism, this book is worth a read—it shows how scientific ideas evolve and why we should never take today’s theories for granted.
If you have thoughts, let me know! Let’s bring this classic into the 21st century.
Thirty-Eight
RETURNING now to the general case of conduction, without regard to the special manner of it, we must notice that, if a current of electricity were anything of the nature of a material flow, there would probably be a certain amount of inertia connected with it; so that to start a current with a finite force would take a little time; and the stoppage of a current would also have either to be gradual or else violent.
It is well known that if water is stagnant in a pipe it cannot be quite suddenly set in motion; and again, if it be in motion, it can only be suddenly stopped by the exercise of very considerable force, which jars and sometimes bursts the pipe. The impetus of running water is utilized in the water-ram. It must naturally occur, therefore, to ask whether any analogous phenomena are experienced with electricity; and the answer is that analogous phenomena are very conspicuous.
A current does not start instantaneously: it takes a certain time—though usually a very short time—to rise to its full strength; and when started it tends to persist, so that if its circuit be suddenly broken, it refuses to stop quite suddenly, and bursts through the introduced insulating partition with violence and heat. It is this ram or impetus of the electric current which causes the spark seen on breaking a circuit; and the more sudden the breakage, the more violent is the spark apt to be.
The two effects—the delay at making circuit, and the momentum at breaking circuit—used to be called extra-current effects, but they are now more commonly spoken of as manifestations of self-induction.
We shall understand them better directly; meanwhile, they appear to be direct consequences of the inertia of electricity; and certainly, if electricity were a fluid possessing inertia, it would behave to a superficial observer just in this way.
Thirty-Nine
But if an electric current really possessed inertia, as a stream of water does, it would exhibit itself not only by these effects but also mechanically. A conducting coil delicately suspended might experience a rotary kick every time a current was started or stopped in it; and a coil in which a steady current is maintained should behave like a top or gyrostat and resist any force tending to deflect its plane.
Clerk Maxwell has carefully looked for this latter form of momentum effect and found none. He took a bar electromagnet, mounted it on gimbals so that it was free to rotate if it wished, and then spun it rapidly about an axis perpendicular to the magnetic axis. If there had been the slightest gyrostatic action, the magnet would have rotated about the third perpendicular axis. But it did nothing of the kind. One may say, in fact, that nothing like momentum has yet been observed in an electric current through solids or liquids by any mechanical mode of examination.
There is a now well-known exception in the case of gases; but it is safe to say that a coil or whirl of electricity does not behave in the least like a top.
Section One Hundred and Eighty-Five
I have looked for the effect in another way suggested by Maxwell, namely, by starting and stopping a current in a freely suspended coil and watching for recoil kicks at the instants of varying current strength. Terrestrial magnetism and the reaction between fixed and movable parts of the circuit caused spurious effects; but when these were reduced to a minimum, by the thick soft-iron case of a marine galvanometer and other suitable precautions, no certain residual effect due to change of momentum could be perceived. The experiments were by no means final, but they were sufficient to show that to detect any possibly existent effect of the kind, considerable refinement must be employed.
Suppose, however, that highly refined experiments directed to the same object still gave a negative result, would that prove that a current has no momentum of any kind? Not necessarily. It might be taken as suggesting that an electric current consists really of two equal flows in contrary directions, so that mechanically they neutralize one another completely, while electrically—that is, in the phenomena of self-induction or extra-current—they add their effects.
Or it might mean merely that the momentum was too minute to be so observed. Or, again, the whole thing—the appearance of inertia in some experiments and the absence of it in others—may have to be explained in some altogether less simple manner, to which we will proceed to lead up.
Condition of the Medium Near a Current
Forty
So far we have considered the flow of electricity as a phenomenon occurring solely inside conductors, just as a flow of water through pipes is a phenomenon occurring solely inside them. But a number of remarkable facts are known which completely negate this view of the matter. Something is no doubt passing along conductors when a current flows, but the disturbance is not confined to the conductor; on the contrary, it spreads more or less throughout surrounding space.
The facts which prove this have necessarily no hydraulic analogue but must be treated suorum generum, and they are as follows:
- A compass needle anywhere near an electric current is permanently deflected so long as the current lasts.
- Two electric currents attract or repel one another, according as they are in the same or opposite directions.
- A circuit in which a current is flowing tends to enlarge itself so as to enclose the greatest possible area.
- A circuit conveying a current in a magnetic field tends either to enlarge or to shrink or to turn partway around, according to the aspect it presents to the field.
- Conductors in the neighbourhood of an electric circuit experience momentary electric disturbances every time a current in it is started or stopped or varied in strength.
- The same thing happens even with a circuit conveying a steady current if the distance between it and a conductor is made to vary.
- The inertia-like effects of self-induction, or extra-currents, can be almost abolished in a covered wire by doubling it closely on itself, or better by laying a direct and return ribbon face to face; whereas they may be intensified by making the circuit enclose a large area, more by coiling it up tightly into a close coil, and still more by putting a piece of iron inside the coil so formed.
Nothing like any of these effects is observable with currents of water; and they prove that the phenomena connected with the current, so far from being confined to the wire, spread out into space and affect bodies at a considerable distance.
Forty-One
Nearly all this class of phenomena were discovered by Ampere and Faraday, and were called by the latter current-induction. According to his view, the dielectric medium round a conducting circuit is strained and subject to stresses, just as is the same medium round an electrically charged body.
- The one is called an electrostatic strain.
- The other is called an electromagnetic or electro-kinetic strain.
But whereas electrostatic phenomena occur solely in the medium—conductors being mere breaks in it, interrupters of its continuity, at whose surface charge effects occur but whose substance is completely screened from disturbance—that is not the case with electro-kinetic phenomena.
It would be just as erroneous to conceive electro-kinetic phenomena as occurring solely in the insulating medium as it would be to think of them as occurring solely in the conducting wires.
The fact is, they occur in both—not only at the surface of the wires, like electrostatic effects, but all through their substance. This is proved by:
- Conductivity increases in simple proportion with sectional area.
- Every part of a conductor gets hot.
- In the case of liquids, by their decomposition.
But the equally manifest facts of current attraction and current induction prove that the effect of the current is felt throughout the surrounding medium as well, and that its intensity depends on the nature of that medium.
We are thus wholly prevented from ascribing the phenomenon of self-induction or extra-current to simple and straightforward inertia of electricity in a wire, like that of water in a pipe.