This one was made of more intangible and abstract stuff than fire, iron, or even steam. And there is another important difference in how electrical knowledge developed. The early pioneers were not usually iron mongers, blacksmiths and "Cornish foremen" (to quote Herbert Hoover) but were more likely to be scientists who had little connection with industry. Even as the potential applications of electricity were becoming obvious, they still concentrated their energies on solving the riddles which surrounded it.
From about 1800 there were a succession of discoveries which over the next three decades would lay the foundations of the profession of electrical engineering. An outline of the milestones is as follows:
It was much more difficult to make progress in this new science (electricity) with the old tools of physical experiment and trial and error. Watt was able to improve Newcomen's engine without knowing a lot of thermodynamics, but it is much more difficult to know what you are doing in electricity if what is going on inside these wires cannot be analyzed and predicted. The more formal tools of science and mathematics were finding a use, even in engineering. (What a novel idea!). Georg Simon Ohm (1787-1854) was a struggling mathematics teacher in a German university. By working with electricity in his spare time, he was able to provide a mathematical model without which we could not get very far in electrical engineering. In spite of the early unfavourable reception of his publication in 1827 of what came to be known as Ohm's Law, ("a web of naked fancies, the sole effort of which was to detract from the dignity of nature...", etc quoted in "Basic Circuit Analysis" Johnson, et al, Prentice Hall 1995) he went on to be honored in his lifetime, and his name is forever with us in the unit of electrical resistance.
A very important observation by the Danish physicist H. C. Oersted in 1819 (this was the year that James Watt died) demonstrated the long suspected connection between electricity and magnetism. As we all know from elementary physics, he observed that a current carrying wire deflected a compass needle (i.e. a magnetized piece of iron), thus demonstrating that an electric current produced what we now call a magnetic field around the wire which carried the current. What is more, this "field" obviously caused a mechanical force to exist. This ability to create a force to act at a distance was very new. Everyone (since Newton) was familiar with the naturally occurring gravity force, and even the attractive and repulsive forces due to magnets, but creating a force by making a current flow was earth-shaking in its implication.
By the way, Oersted was very important in engineering education in Denmark. About the same time that he was making this fundamental discovery, he founded the Technical University of Denmark, which today is the country's major engineering university. The venerable University of Copenhagen was there, but like Oxford and Cambridge in England, did not see any need to get involved in the teaching of all this new-fangled stuff.
Following on from Oersted, it was not long before the Frenchman Andre Ampere (1775-1836) made the corresponding discovery that a current carrying wire experienced a force when placed near a magnet - i.e. in the magnetic field, as we would say now. The basis for an electric motor was now in hand. Make a wire loop, and place it on an axle between the poles of a magnet, and arrange to change the current direction every half turn, and you have it. See sketch.
No one seemed to put it together just like that, but a British genius named Michael Faraday (1791-1867) did make a device which demonstrated the motor principle in 1821. But he and others were fascinated by another puzzle. If you could produce a force and mechanical motion from electricity, it should be possible to use mechanical means to do the reverse - i.e. generate a current. Another question - and it turned out to be part of the same puzzle - was whether a current in one circuit could somehow produce one in another which was not physically connected to it. On the basis of the observed magnetic effects of currents, it seemed reasonable to expect this, and Faraday discovered how to do it in 1831. He observed, unexpectedly, that when he switched off the current in one circuit, there was momentary burst of current in the other, nearby circuit. Thus it was not the presence of the primary current which created the secondary one, but the change in it that mattered, and the key action was the relative motion of the wire and the field. He had discovered electromagnetic induction, making it possible to build generators, motors, and transformers, and so to open up a whole new source of power.
Over the next ten years or so, numerous improvements and inventions were made, some now running ahead of the science.
Some of the Applications.
One of the earliest uses of this new magical power was to sell it to cure illness. Electrotherapy - i.e. electric shock - and the application of strong magnetic fields was thought to be good for you. But the more lasting benefits ran in three different directions: communications, lighting and machinery.
Railways had a need. One of the pressing requirements with the newly developing railways was to find a way to signal ahead of the train so that people knew where the train was, the proper switches could be set to avoid collisions, and for management of the traffic. I K Brunel had a hand in this, having developed a mechanical system. The first practical electric telegraph, which used needles to point to letters, was installed on one of his lines.
Morse and his code. But on the other side of the Atlantic, a man by the name of Samuel Morse, (a professor of painting and sculpture, as we have seen) together with some friends figured out that if switching on and off a current in a coil around a bar of iron, i.e. an electromagnet, would cause another piece of iron (the armature) to move, then this could be used to make a signal, and one could communicate along the wires. The electromagnet would hold the armature down while the switch was closed. But there needed to be a better way of getting the information rate up than that allowed by the early slow arrangements to point to letters. (Charles Wheatstone (1802-1875) was involved in some of this early effort).
Morse's his chief contribution was to invent the code, known by his name. It is, of course, a binary code - two elements, dot and dash. He apparently researched newspapers to see which letters were most used, and the most frequent ones get the simplest code. No more than four bits are needed for any letter.
At the receiving end, the electromagnet was set up so that a strip of paper moved along in front of a pencil that pressed on the paper when the switch was closed, and the familiar dots and dashes could be sent. In 1844 Morse sent his famous message from Washington to Baltimore: "What hath God wrought".
A flourishing technology. The whole world was soon connected by a network of wires, including cables under the oceans, and we have seen how Brunel's Great Eastern figured in some of this. The South Atlantic was traversed by cable in 1874, and the Pacific Ocean in 1901. Dozens of cables came into Trinity Bay, Conception Bay, and other points in Newfoundland. (See Tarrant, references, which has been a major source of much of my information on the Newfoundland connection to telegraphy.)
In the early days, the "signal" consisted of simply interrupting the current by opening and closing a switch. An early innovation was a "double key". Pressing in one direction sent a positive voltage ("dot") and in the other direction a negative voltage was sent ("dash"). Ingenious methods of transferring these signals to a paper tape (e.g. a "siphon galvanometer", see Tarrant) greatly improved reliability and speed. The limit of manual transmission, which was about 50 words per minute was soon gotten over by preparing a paper tape and subsequently running it through a transmitting apparatus at up to 400 words per minute.
Voices on the wire. The next big step was to get away from that code, and talk directly to the wire. It is not altogether surprising that the person to do this was someone who understood the properties of speech. He was, of course, Alexander Graham Bell, who was an expert teacher of deaf people, again, like Morse, not an engineer or scientist. What was needed was some contrivance to superimpose variations in air pressure, which constitute speech, on an electrical current flowing in the wire. A box with flexible walls and filled with carbon particles became a rudimentary microphone, (this was a contribution by Thomas Edison see - Matschoss, Great Engineers p321) and every school kid knows that Mr. Bell told Mr. Watson to "come here" in 1875.
Can we get rid of the wire? Among the new breed of telegraph engineers there were those who dreamed of ways to get rid of the wire. They could see that the inductive principle could be used; by opening and closing a switch in one coil, a corresponding current variation appeared in another, as long as it was not too far away. If an oscillator were set up and generated audio frequency signals, then these signals could be detected by an simple electromagnetic earphone in a loop or coil some distance away. Among those who experimented w with wireless telegraphy of this sort was engineer and physicist Oliver Heaviside (1850-1925). But coils linked by only magnetic induction were not practical over any more than short distances unless the coils were unreasonably large.
James Clark Maxwell (1831-1879) But science was again catching up, and the chief person responsible was Sir Michael Faraday's assistant, James Clark Maxwell (1831-1879). By the way, Faraday was once asked what his greatest discovery was, and he replied "James Maxwell". Maxwell was trying to understand the science of what his mentor had discovered - electromagnetic induction.
Light and electromagnetism. He was also convinced, as was Faraday, that there was some connection between light and electromagnetism. Light was supposed to have some kind of vibratory motion, and looking for a model that had something to vibrate, scientists had proposed an invisible, elastic mass less medium which they called "aether" or ether, to use the modern spelling.. This was very much a postulate, or hypothesis, but was serving until they found something better. It was hard to conceive of wave motion without a medium. The ether hypothesis was eventually disproved by the famous Michelson - Morley experiment in 1887.
But we digress. Maxwell at first used a rather mechanical model involving the ether to explain electromagnetic induction, but he apparently still felt that it should not be essential. He was not too concerned with physical models in any case, and as electricals know, or will soon find out, in 1865 he published the theory (A Dynamical Theory of the Electric Field) for a set of equations which now bear his name and form the basis of all electrical and magnetic phenomena, including light. (NB: The Great Eastern was setting out for Newfoundland with the first cable that year). The theory does not depend on the existence of the ether. Very few people understood it, and some eminent people at the time doubted that the velocity of propagation could be finite, as was being predicted.
The resulting physical model given by Maxwell's theory is not difficult to explain, if we can visualize "fields". A varying electric field must create a varying magnetic field, and vice versa. As one collapses, the other grows. Their lines of force are mutually perpendicular, and the wave travels in a direction perpendicular to them both with the velocity of light.
Maxwell's theory led on to experiments by Heinrich Hertz (1857-1894), who demonstrated in 1886 that such waves could be detected, verifying the theory - and paving the way for another fantastic development.
Guglielmo Marconi (1874-1937) But the initiative to put this knowledge to use in the world came not from the established scientific community but from a young fellow from Italy. He was well-to-do and informed, but hardly a leading scientist or engineer. However, he was certainly an inventor and risk taker. His name was Guglielmo Marconi (1874-1937). He had listened to the day's scientists, and read their papers, and did experiments based on the work of Hertz, who died prematurely young in 1894, at the age of only 37.
Marconi invented a practical antenna, and in 1901 was here in St. John's to receive the faint clicks of a Morse code "s" sent from England. There was no joy in the offices of the Anglo-American Telegraph Company on this occasion, and due to their pressure on the local government, and the monopoly obtained by Cyrus Field in the 1854, Marconi was definitely not made welcome to continue his experiments here, and went elsewhere.
Students can read more about Marconi in the "Great Engineers" document, on our web site. By the way, he continued to make important contributions to science and engineering, and was awarded (jointly with K F Braun) the Nobel Prize for physics in 1909.
Although the first cables (and there were many more - the 1866 cable
was no longer usable by 1873, see Tarrant) had been landed in Heart's Content
only about 40 years before, the end of that technology was now in sight.
The last telegraph cable was laid into Newfoundland in 1953. The
Content office (then of Western Union) finally closed in 1965. Telephone
cable traffic more and more replaced telegraph through the 60's and 70's,
and that too is now gone. By the late 90's the only underwater communications
cables to operate to Newfoundland were two large fibre optic connections
across the Cabot Strait.
Probably the most apparent consequence of electricity to touch the ordinary person, and for that matter, industry, was its application to turn night into day. Until about 1800, only candles and crude animal oil lamps lit the night. About that time, coal gas lighting came along. Among the early developers, by the way, were our friends at Boulton and Watt, in Birmingham. Furthermore, "Colonel" E L Drake bored a hole in the ground in Pennsylvania in 1859, and discovered petroleum, for which the main use until automobiles came along was to make it into kerosene and use it for lighting. So by the late nineteenth century, coal gas and kerosene lit streets, factories and homes. (For the story of the discovery of petroleum, see Daniel Yergin, references)
The first lighting from electricity depended on the arc generated when a circuit was broken. This was done by having two carbon rods close enough for the arc to jump, and this technique goes back to 1808. But it was a very unsatisfactory system, smelly, smoky and hot. The real solution was invented more or less simultaneously by Thomas Edison (1847-1931) and Joseph Swan (1828-1914) in the late 1870's. This was, of course, the incandescent bulb. In addition to finding a reasonably good filament material, the main problem had been getting a sufficiently good vacuum. With a newly invented pump from Germany, Edison managed to get it down to one millionth of an atmosphere. Edison and Swan were very much in competition at first, but eventually formed the Edison and Swan United Electric Company. Before the nineteenth century finished, electric light was spreading everywhere.
Before the applications of electricity on a large scale could get going, engineers had to find the means to generate electricity on a large scale, and distribute it to potential customers. Note that it was now all engineering, running ahead of the science again. Science was now involved with the discovery of the electron, etc.
Soon after Faraday discovered the induction principle, work was taking place on ways to turn mechanical energy into electrical. Initially a permanent magnet was used to produce the field, then German engineers pioneered the use of electromagnetic windings and the "dynamo" came into being. The first power station in the world was put into operation in New York by the Edison Company in 1882, transmitting power at 110 v dc. Edison's company eventually became General Electric.
Direct current had some advantages, and had many supporters at first. But one of the people who was fascinated with alternating current, and all the amazing effects of electrical resonance, was the eccentric genius and engineer whose picture we saw at the beginning - Nikola Tesla.(1856-1943). (See Cheney, references) He invented the real workhorse of rotating machinery, the simple poly phase induction motor, and the transformer. Some of his eccentricity was demonstrated by the project to transmit large quantities of electrical power without wires. A tower to do this across the Atlantic was actually built in New York in 1901-03.
Tesla's ideas on the advantages of ac power attracted the attention of George Westinghouse, and after much competition, not all of it honorable, the Westinghouse Company got the contract to develop the water power of Niagara Falls, with an ac plant. By 1896 ten 5000 horsepower turbines were supplying Buffalo with electricity. The electric age was well under way.
Our lectures in the history of technology have essentially dealt with the 19th century, with a bit of attention to the previous century. This is, say, 150 years, and we have not seen anything of mass communication (radio, TV), flight, space travel, or computers, let alone the web! All of these come in the twentieth century, much of it in the last 50 years. Engineers have been involved in all of it - often leading it; sometimes building on scientific discovery, but also sometimes uncovering problems which scientists then unravel, probably leading to still more technological development.
But does it all lead to the unadulterated betterment of the human condition? Some people don't think so, and we will examine that in the next part of the course.
Tarrant, D R. Atlantic Sentinel Newfoundland's Role in Transatlantic Cable Communications. Flanker Press, 1999.
Yergin, Daniel. The Prize. Simon and Shuster, 1991.
Cheney, Margaret . Tesla, Man Out Of Time. Dell Publishing Co, New York, 1981.
Matschoss, Conrad. Great Engineers. Books for Libraries Press, New York, 1970.