Prof. Doug Jones
This is the fourth installment in our series of stories about people whose names we know yet we know little about them. This month we are going to meet James Watt. James Watt is, of course, known as the one who developed a practical steam engine, which ushered in the industrial revolution. How did an inventor of steam engines get the unit of power named after him? We'll find out. But first, let's define our term. The rigorous definition of the Watt is:
the absolute meter-kilogram-second unit of power equal to the work done at the rate of one joule per second or to the power produced by a current of one ampere across a potential difference of one volt”
Sometimes people get confused about the difference between energy and power. I found this wonderfully simple explanation and example on the KQED website;
“Energy is what makes change happen and can be transferred from one object to another. Energy can also be transformed from one form to another.
Power is the rate at which energy is transferred. It is not energy but is often confused with energy. The watt is the most commonly used unit of measure for power. It measures the rate of energy transfer.
A watt equals a joule per second. If a smart phone uses five joules of energy every second, then the power of the phone is five joules per second, or five watts.”
So once again, in our imperfect water analogy, if Volts is the amount of water stored in a huge water tank many feet off the ground, (potential energy) and current in Amperes is the amount of water flowing through a pipe whose size would represent the resistance in Ohms, (the bigger the pipe the less resistance) then power in Watts is the amount of water per unit time flowing through the pipe. It is a measure of how much work could be done. If you imagine a water wheel at the end of the pipe, obviously a large flow of water will get more work done than a trickle will. This is part of Ohm’s law that we saw a few months ago. Power in Watts is equal to I (current in amperes) times E (EMF in Volts) or P= I x E.
James Watt was born in Greenock, Scotland in 1736, 53 years before Georg Ohm was born. This makes him the oldest of the men we have looked at so far. So, the world in 1736…. Sir Isaac Newton had died only 9 years earlier, and some of his major works were just being published. In what was to become the United States, Benjamin Franklin launched the very first organized volunteer firefighting company. He named it The Union Fire Company. Elsewhere, the great Swiss Mathematician Leonhard Euler was very active. 1736 marked the dedication of the great Silbermann pipe organ in Dresden. It consisted of 3 manuals, and 43 ranks, huge for its day and a well-sized instrument by even today's standards! In December of that year, JS Bach gave a recital on the great Silbermann organ. In 1736 King George II was on the throne in Great Britain. Watt was born 52 years before the first penal colony was established in Australia. Of course, Africa was still unexplored by Europeans and China was embroiled in the Qing dynasty and the subjugation of the Ming, a process that lasted 65 years and cost some 25million lives! 
century as a whole was a century of chaos in South America with Europe trying to control as much of it as they could. This was the world that welcomed James Watt.
James Watt was born into a fairly successful family. His grandfather was a math teacher and his father was a shipbuilder. James’ mother, Agnes Muirhead, was also very well educated and taught James how to read. By all accounts, James was a “fragile child” who suffered from a number of ailments. 
He was homeschooled for a while and developed an interest in making things. His father set him up with his own workbench complete with tools and forge and young James developed a knack for building models as well as mathematical instruments like quadrants, compasses, and scales. Eventually, he did attend school and learned Latin, Greek, and Mathematics. By his mid-teens, Watt decided to become an instrument maker. Apparently, there were two disasters that struck at about the same time. A ship that his father had heavily invested in sunk and that financial loss just about ruined him. At roughly the same time, his mother died. Realizing that there was little future for James in Greenock, his father sent him to Glasgow in 1754. The story of how James navigated life and the twists and turns that made him the man he was to become is fascinating, but unfortunately beyond the scope of this overview. The opportunity that really changed everything came in 1763 when he was 27 yrs. old. By now James was working for the University of Glasgow as a sort of independent contractor building scientific instruments. One day a professor at the university brought James a problem. The university had a scale model of a steam engine pump called a Newcomen Pump. These pumps had become widespread in England and Europe at the time and were used to pump water out of mines. They were extremely inefficient. The university was given the task to figure out why the Newcomen engine was so inefficient, so they built a scale model so they could investigate the problem… but the scale model would not run! James by now had a reputation of being good at building and fixing things, so the professor asks him to see if he could get the model running. Watt was not only able to fix the model, but in so doing he discovered the reason that these engines consumed such huge quantities of steam and fuel. The solution to improving the Newcomen engine took over two years of study. By 1765, Watt built his first small-scale steam engine that was significantly more efficient than the Newcomen. In 1769 Watt patented his engine. The patent called “ A New Method of Lessening the Consumption of Steam and Fuel in Fire Engines” 
is now thought to be one of the most important patents ever issued because the efficient harnessing of steam ushered in the industrial revolution. In 1775 Watt entered into a partnership with an industrialist of some means, Matthew Bolton, which lasted over 25 years. During that time, Watt kept making improvements to the engine. In 1781 he invented a way to make the reciprocating action into a rotary one, making his engine suitable for use in far more applications than simply pumping water. By 1790 he had added a centrifugal governor that could keep the engine at a constant speed and a pressure gauge to monitor the boiler pressure.
Observant readers will probably by now realize that the story of Watt does not include anything about electricity. It is interesting that the man whose name is associated with electrical power was not a pioneer in electricity at all. The other three greats, Volta, Ampere and Ohm, all were heavily involved in discoveries and inventions pertaining to electricity. Watt was interested in power! In 1782, a sawmill ordered an engine that would replace a team of 12 horses. In order to figure out how much power the steam engine had to deliver he needed to ascertain the power that 1 horse could produce. Watt used data provided by the sawmill and figured out that a horse could lift 33,000 pounds a distance of 1 foot in one minute. He called this 1 horsepower! We still use this unit to rate the output of engines of all types.
Unlike many inventors and innovators of his time, Watt did live to see his inventions succeed and enjoy the fruits of his labors. Not only did Watt achieve considerable wealth from his steam engines, he also won acclaim from the academic and scientific institutions of his day. In 1785, Watt and Bolton were elected fellows of the Royal Society of London. He was given an honorary Doctorate from University of Glasgow in 1806 and in 1814 he was made a foreign associate of the French Academy of Sciences. 
James Watt died in 1819. His mind was keen right to the end.
He almost single handedly transformed the western world from one being based in agriculture to one based on engineering. It is fitting he should be recognized by naming the unit of power
It is interesting to note that the unit of horsepower and the Watt are essentially the same thing, just expressed differently. 1 horsepower = 745.7 Watts! So, I could say that my Goldwing can develop 87,246 Watts. In fact, in Europe and Australia it is common to rate the output of an engine in Watts or Kilowatts. We could also say that the Danley J5 Caleb is a 53.6 HP loudspeaker!
We have now covered the 4 most prominent names in our business: Volta, Ampere Ohm and Watt. Next month we will continue with the series, but look at some folks who are just a bit more obscure, like Faraday, Henry and Coulomb.