INTRODUCTION

The Industrial Revolution in England began in 1762 and lasted to 1840. It was one of the most important periods in human history—primarily because of its profound influence on the daily life of average people. In particular, the standard of living was increased, but there were still major problems with conditions.

The era was significant for the military. It changed the way armies were equipped and how they fought, and it introduced mass production, which was something new in the civilized world. Guns, ammunition, and other weapons of war could now be easily produced by the thousands. And of particular importance was that weapons manufacture was standardized so that parts were interchangeable and could easily be replaced.

What role did physics, and science in general, play in this revolution? As it turns out, there is some controversy. There's no doubt that the developments spurred interest in physics; and new branches of physics actually arose as a result. But how much did the earlier breakthroughs of Newton, and the breakthroughs that occurred during the Industrial Revolution, relate to physics? The problem here is the definition of “science,” and more particularly “physics.” Many argue that “pure physics” made little contribution. And indeed it is true that the major contributions came from applied physics and technology, as most of the advances were actually engineering advances.

Nevertheless, there were dramatic changes in society—mostly for the good, although for the lower class, smog from the new blast furnaces (which used coal as fuel) was something new and unhealthy. And there's no doubt that the Industrial Revolution had a huge effect on war and warfare.

THE FRENCH REVOLUTION

For the most part the Industrial Revolution took place mainly in England, at least in the early years, but looking back in history it's easy to see that its origins were in France. However, it didn't play out fully in France until it was well underway in England.

The origins of the Industrial Revolution can be traced to Louis XIV of France, who ruled from 1643 to 1715. He had the longest reign of any French king—seventy-four years. He became king when he was four years old, but the Queen Mother and her assistant wielded power until he was twenty-one. When he took over, England's navy ruled the seas, and the French army was no match for the highly trained English army. Louis, who was convinced that his power was given to him by God and that he was accountable to no one except God, decided to make France the strongest country in Europe, and to do it he would have to build up its army and its navy. Furthermore, if these were to be first rate, they would have to have first-rate weapons, strategies, and tactics. And he was determined to make this come to pass. Strangely, though, he had no interest in “leading” his armies into war as Adolphus of Sweden had done, and he cared little about new developments in technology, or science in general. His major interest was dancing and partying at his many palaces (he built the immensely plush palace at Versailles). Fortunately, he had a very competent finance minister named John Baptiste Colbert, and he put Colbert to work upgrading the army and navy. And indeed, Colbert did an excellent job; within a few years France had one of the strongest navies and best-equipped armies in Europe. His navy went from 18 outdated ships to 190 ships equipped with all the modern devices known, and his army increased from a few thousand poorly trained men to 400,000 highly trained soldiers, equipped with the best cannons and muskets available at the time.1

With all of this available to him, Louis decided he was going to expand the borders of France—in essence, he wanted to conquer Europe and defeat the English in the process. He thought of war as a “sporting event,” with himself as commander. He began by attacking Belgium and Holland with his large army. He easily overcame them, but soon other countries saw him as an egotistical aggressor and began to form alliances against him, and, as a result, his losses began to pile up. One of his major losses was the War of Spanish Succession, which started in 1701 and continued to 1714; by the time it ended, France was almost bankrupt. Indeed, throughout much of his long reign he was at war, and by the time he died in 1715 he was highly unpopular.²

Even though he was unsuccessful in his expansionist ambitions, he did make the important contribution of starting the Industrial Revolution. It all began with gunpowder. He wanted gunpowder produced fast and efficiently, and the methods that were in use at the time were too slow, so he directed his ministers to build a huge workshop in Paris for producing gunpowder. In it he set up what was probably the first “assembly line” for mass production. Production underwent several steps, with groups of people involved in each step, where each group performed only one operation before passing the product on to the next group. It was a new tactic, and it worked wonderfully. Soon he had warehouses full of gunpowder.

From here he turned to the production of guns—both cannons and muskets—and he set up an assembly line for them. He mass-produced uniforms in another assembly line. From here the new revolution could have spread and made France the greatest industrial nation on earth—but it didn't. By the end of Louis's reign France was nearly bankrupt. As a result, the major part of the Industrial Revolution took place in England.

THE ENGLISH REVOLUTION

The revolution in England, which began about 1760, was fueled mostly by three technical advances: James Watt's steam engine, John Wilkinson's new techniques for iron production, and new techniques in the textile industry. Several developments in the chemical industry, along with the development of new machine tools, were also helpful.3

With the advent of steam engines, efficiency increased dramatically. But for the early part of the revolution, industry still relied on waterpower, wind, and horses for driving small engines.

The first successful steam engine came in 1712. It was invented by Thomas Newcomen, based on experiments performed thirty years earlier by Christiaan Huygens and his assistant, Papin. It consisted of a piston and cylinder, with the end of the cylinder above the piston open to the atmosphere. Steam was introduced in the region below the piston. This steam was condensed by a jet of cold water, producing a partial vacuum. The pressure difference between the vacuum and the atmospheric pressure on the other side of the piston caused the piston to move downward in the cylinder. It was attached to a rocking beam that in turn was attached to a water pump.

Newcomen's steam engines were used in England for years for draining the water in mines. But it was the improvements to the design made by James Watt that provided the major breakthrough to the Industrial Revolution. Other things that played an important role in the revolution were the development of new machine tools such as the lathe and various planing and shaping machines. Cylindrical boring machines were also important in relation to war, and they were used for boring cannons. Much of this was made possible, however, by the conversion from wood or charcoal to coal in the large furnaces of the time.

The development of new chemicals, such as sulfuric acid, sodium carbonate, alkali, and so on, was also important. Portland cement was also used for the first time during the Industrial Revolution.

JAMES WATT AND THE STEAM ENGINE

The major breakthrough that made the Industrial Revolution possible was the invention of the steam engine by James Watt. Initially it was just an improvement on Newcomen's model, but it proved later to be much more than that. Born in a well-to-do family in Greenock, Scotland, in 1736, Watt did not attend a regular school during his early years. He was home-schooled by his mother, but later on he did attend Greenock's grammar school. From an early age his skills in mathematics were obvious, but he also liked to build things. When he was eighteen he went to London to study instrument making. Later, he set up a shop in Glasgow as an instrument maker; in particular, he specialized in scales and parts for telescopes, barometers, and various other instruments of the day. His skills came to the attention of the physics and astronomy department at the University of Glasgow, and he was offered the opportunity to set up a small workshop at the university so he could help monitor and repair the instruments used there. As a result he became friends with several of the university personnel; in particular, the well-known physicist Joseph Black (an expert on heat) became his confidant and mentor.4

In 1759 another friend, John Robinson, told him about the problems of the Newcomen steam engine, and he was asked to repair a Newcomen engine belonging to the university. Looking into the design of the engine, Watt soon realized that it was extremely inefficient. In short, it was wasting much of the energy it was producing because three-quarters of the heat of the steam was being consumed in heating the engine cylinder during each cycle. The main reason for this waste was the cold water that was injected into the cylinder to condense the steam to reduce its pressure. Much of the energy, therefore, was going into repeatedly heating the cylinder.

Watt redesigned the engine so that the steam condensed in a separate chamber away from the piston. In addition, he maintained the temperature of the cylinder by surrounding it with the steam “jacket.” This meant that most of the heat from the steam would now be performing work. This improved the efficiency and power of the engine dramatically. Watt built and demonstrated his new machine in late 1765. Surprisingly, though, even with its obvious advantages and potential, he had trouble finding someone to back him in producing it commercially.

Eventually, though, he was introduced to Mather Bolton, the owner of a foundry near Birmingham, and they became partners. Over the next few years the firm of Bolton and Watt became very successful. Watt continued to improve his machine and soon converted it so that it would produce rotational power. This proved to be a boon in grinding, milling, and weaving. Later he developed a compound engine, in which two or more engines could be used together.

But there was still a problem with the largest engines: the piston in the cylinder did not always fit tightly. This problem was solved by John Wilkinson.

JOHN “IRON MAD” WILKINSON

In 1774 John Wilkinson made a significant breakthrough in the construction of cannons. For years cannons had been constructed of iron that was cast with a core. Any imperfections in the interior were removed by a quick bore job, but this created a serious problem: each cannon was slightly different, and parts therefore had to be custom made. They could not be interchanged from cannon to cannon. Wilkinson showed that casting a solid cylinder and boring a hole in it by rotating the barrel produced much more accurately machined cannons, which would allow for the interchangeability of parts. It also made the cannons much less likely to explode during manufacture. As a result, the production of large cannons was improved. Watt's new steam engines helped Wilkinson produce more large guns with less labor, and Wilkinson's new techniques with iron and steel helped Watt build bigger and better steam engines. The partnership was of great benefit to the English military. Many of the large cannons were installed on ships, helping to make England's navy even stronger.5

Although Watt probably didn't realize it, his work was also critical in the development of a new branch of physics, called thermodynamics. Thermodynamics is primarily concerned with studying and improving the efficiency of all kinds of heat engines, and it would soon become an important branch of physics.

The work of Wilkinson and Watt was, without a doubt, critical to the military, but it created a problem. Wilkinson soon began to realize he was indispensable, and he began to think that the British military was not compensating him sufficiently. He was ambitious and wanted to expand his iron and steel empire, but he needed more money, and it looked like his chance of getting much more from the British military was slim. And he also knew that other countries would be eager to pay for his knowledge and technology, France in particular. So, without mentioning it to the British authorities, he met with some French diplomats, and, as expected, they were eager to buy his cannons. But there was, of course, a problem: How could he ship them to France without alerting British custom officials? He got around this by labeling his exports as large iron “pipes.” And France paid him so well that he soon became a very rich man.

BENJAMIN ROBINS

While advances were being made in the construction of cannons, advances were also being made in the construction of muskets, particularly in relation to their accuracy. And as it turned out, physics was critical to these advances. Most of these advances were associated with one name: Benjamin Robins.

Robins was born in Bath, England, in 1707 to Quaker parents. His father was a tailor, but the profession brought him little money, and the family was relatively poor. Benjamin's mathematical ability eventually attracted the attention of some of his friends, and a letter was sent to Dr. Henry Pemberton in London. Pemberton sent young Robins a test, and he did so well on it that he was invited to come to London. At the time, Pemberton was preparing a new edition of Newton's Principia, and Robins read it along with many other important works in mathematics and physics. By the time he was twenty, Robins was publishing in major journals and was elected a fellow of the Royal Society (a tremendous honor for anyone so young). He continued to publish extensively; in one publication he defended Newton's new “calculus” from several attacks by would-be mathematicians.6

A new military academy, the Royal Military Academy, was established in 1741. Robins applied for a position, but surprisingly, despite his impressive qualifications, he was turned down. Some people have said that this annoyed Robins so much that he became determined to show the academy what a mistake it had made, and, as a result, he threw himself into the study of the physics of guns, artillery, and projectiles.

After a careful study of the armaments of the day, he was amazed to find out how inaccurate they were. In some battles as many as 250 rounds of ammunition were fired for every enemy killed. In fact, manufacturers didn't bother to put sights on military muskets because they were never used for individual targets. A volley of bullets fired by a large number of soldiers was the main tactic used at the time.

Robins was determined to find out what the major problems were. As a test he fixed a musket in a rigid clamp and set up targets (paper screens) at distances of fifty, one hundred, and three hundred feet. He then measured how far the bullet had strayed off the target (away from a straight line) for each of the distances. He found that at one hundred feet it was off by fifteen inches, and at three hundred feet it was off by several feet. Furthermore, it was off by different amounts in different directions. So much for accuracy. It was no wonder that it was a waste of time aiming at a target three hundred feet away.

Robins immediately asked himself why the accuracy was so poor. There had to be a logical reason. He finally determined that the problem had to do with the spin of the projectile. Spin was not given purposely; nevertheless, when the bullet emerged from the barrel it had some spin, and this spin was different for each projectile. The reason for it was that the spherical projectile was purposely made slightly smaller than the diameter of the barrel, and as it moved down the barrel it struck the sides of the barrel at various points, and each time it hit, its spin changed. The critical change, however, was the last one just before it emerged from the barrel. This would be the spin it had in flight. And Robins assumed (correctly) that this spin was interacting with the air that the projectile was passing through, and this interaction affected its trajectory.

The next problem, then, was to determine the bullet's speed as it emerged from the barrel, and, if possible, its spin. To determine its speed, Robins invented what is called a ballistic pendulum—one of the most important inventions in the history of gunnery. He began by clamping a musket in position. Directly in front of it he placed a large block of wood that was mounted at the end of a wire or rope so that it could swing like a pendulum. Robins found that when the gun was fired the block absorbed the kinetic energy of the musket ball, and, as a result, the block swung through a few degrees on the supporting wire. The kinetic energy of the bullet was being changed into potential energy in the process. Equating the two types of energy, Robins solve the equation for the velocity of the projectile, and he determined that the musket ball had struck the block with a velocity of 1,139 miles per hour. After all of the years that guns and cannons had been used, this was the first time anyone had any indication of how fast the bullets were going. So it was, indeed, a tremendous feat.

Now that Robins had determined the muzzle velocity of the gun, he had to figure out what happened as the projectile traveled through the air to its target. How was its velocity altered? By moving the block of wood farther away from the barrel, Robins could find out. And it was soon obvious to him that the bullet was losing velocity rapidly. In fact, a bullet lost almost half its initial speed in the first hundred yards. The air through which the musket ball moved was obviously having a serious effect. Scientists and engineers of the time knew that air caused drag on a musket ball, but they didn't realize how dramatic the effect was. The basic problem was the shape of the projectile: a sphere. A sphere was not as aerodynamic as other shapes, and Robins soon realized this. What was the best shape to minimize atmospheric drag? The answer, at least to some degree, was already known. Archers had experimented with different types and shapes of arrowheads over the years, and they had found that the most dynamic arrow tip appeared to be one that was elongated and shaped to a point. But there was a problem with an elongated musket projectile with a point. It would tumble as it moved through space, making things even worse.

Robins analyzed the problem carefully, and, in doing so, he realized that there were actually two problems: finding the most aerodynamic projectile, and getting rid of the random spin as it left the barrel of the gun. Robins soon found that he could solve both of these problems with one significant change. He would give the bullet an elongated form with a pointed end, and he would cause it to spin around an axis through its center in the elongation direction. The best way to do this was to score the inside of the musket barrel with a series of spiraled grooves. In other words, he decided to “rifle” the barrel. But the grooves would only work—give the bullet is spin along its central axis—if the bullet fit into the grooves. In short, the grooves had to bite into the lead as the bullet moved down the barrel. In fact, it was soon shown that the ideal size for a bullet was slightly larger than the diameter of the barrel.

Finally, Robins drew up plans for a breach-loaded gun; this was a gun in which the breach could be opened so that the charge of powder and a bullet could be inserted into the barrel. With the powder and bullet in place it could then be securely closed so that it was ready for firing. This was a significant breakthrough, but it wasn't actually used until several years after Robins's death. Rifled muskets were a problem technologically, so they didn't really take off for another few years. Nevertheless, Robin's breakthrough revolutionized military warfare, and it soon made England one of the strongest countries in Europe.

THE FLINTLOCK

The basic musket of the time also underwent a significant change during this era. The change was introduced early in the seventeenth century, and by 1660 the new musket became the major European military musket, and it continued to be used until about 1840. Most muskets of the time had smooth barrels and fired lead balls. They had a range of about 150 yards, and they weighed about ten pounds. When rifling began to be used on the barrels it gave them considerably better accuracy and a much greater range. But for the most part, rifled muskets were used only by sharpshooters (or what we might call snipers). The problem was that the rifled musket took much longer to load because of the use of tight-fitting bullets. Furthermore, the barrels of the rifled muskets (now called “rifles”) had to be cleaned after each shot, and this took too much time.7

The major difference in this new rifle, called the flintlock, compared to the wheel lock, was the use of a piece of flint to create sparks. A person firing a flintlock would cock the gun by using his or her thumb to pull a lever back against a strong spring (see diagram). At the end of the lever was a piece of flint with a point on it. As in the case of previous guns, the flintlock had a flash pan that was loaded with finely ground gunpowder. When the flash pan was primed it was closed. On the top of the flash pan was a steel striking plate called a frizzen, and when the trigger was pulled, the spring would force the flint down toward the plate. When it struck the frizzen it caused the pan to open. And as it slid down the frizzen it created a shower of sparks. The sparks would ignite the powder in the flash pan. As a result, a flame would flare down through the touchhole and ignite the charge in the barrel.

Close-up of the flintlock mechanism.

The flintlock mechanism was used on both rifles and pistols. By now, in fact, military pistols were becoming quite common; they had a relatively short range, but they were easy to handle, which made them popular with the cavalry. The smaller flintlock pistols were about six inches long; larger ones were about sixteen inches long. One of the most popular pistols was the Queen Anne pistol. This elegant and beautifully designed gun was frequently the weapon of choice for dueling, which was a popular method of solving arguments at the time. Indeed, some of the pistols even had two, three, or more barrels for quicker shooting.

Although they were a significant improvement over matchlocks and wheel locks, flintlocks had problems of their own. The flint had to be sharp or the gun would misfire. Also, the flintlock was vulnerable to moisture and accidental firing. In addition, occasionally the gun would explode in soldiers’ hands.

CHRISTIAAN HUYGENS

Getting back to the physics of the era, we have one of the greatest physicists to appear after Newton. Unlike Robins and some of the scientists we've discussed so far, Huygens was born into a highly respected and relatively rich Dutch family; his father was a diplomat and part-time natural philosopher who played an important role in Christiaan's early education.8

Christiaan was schooled at home by some of the best local teachers until he was sixteen. It was obvious that he had considerable ability in mathematics, and this came to the attention of a family friend, the eminent mathematician Rene Descartes. Descartes encouraged Huygens to study mathematics at the University of Leiden. And indeed, Christiaan studied mathematics as well as law at the university, beginning in 1645. Over the next few decades he made numerous discoveries in physics, mathematics, and even astronomy, and although they had little effect on the military weapons of his time, his discoveries would have a tremendous influence later on.⁹

In addition to fundamental contributions to mathematics that included the first book on probability theory and solutions to many of the basic mathematical problems of the day, Huygens made major contributions to physics. In 1659, for example, he derived a formula for the force (now called the centripetal force) associated with circular motion, as in the case of a ball whirling at the end of the string. His formula stated that F = mv²/r, where m is mass, v is velocity, and r is radius. He also made fundamental discoveries relating to the elastic collision of two bodies; he was the first to show experimentally that the total momentum before the collision is always equal to the total momentum after the collision (as predicted by Newton's third law). In addition, he invented the first pendulum clock, and he was the first to derive the formula for the period of a pendulum. He also devised new methods for grinding lenses and making telescopes, and he used telescopes to discover the largest moon of Saturn, now named Titan. He also observed Saturn's ring and predicted correctly that it was thin and not attached to the planet.

In the area of physics, however, he is probably best known for his wave theory of light, which he proposed in 1678. A few years later Newton suggested that light was composed of tiny particles he called corpuscles, and for many years there were two theories about the nature of light: one based on waves, and one based on particles. In 1801 Thomas Young showed that Huygens was correct, but today's quantum physics has embraced the concept of wave–particle duality, since light seems to exhibit both properties, depending on one's method of observation.

Huygens also developed a balance spring for clocks and watches that is still used in some modern devices, and in 1675 he patented the first pocket watch. In 1673 he began experimenting with a combustion engine, which he fueled with gunpowder. It was not successful, but he designed a simple form of steam engine that was helpful to James Watt in his work.

PHYSICS AND THE INDUSTRIAL REVOLUTION

As mentioned earlier, a number of scholars have suggested that pure science (including physics) played only a minor role in the development of the Industrial Revolution. But if you look at the overall picture, it's easy to see that many fundamental discoveries in physics took place during this time, most notably those of Huygens. In addition, both the Royal Society in England and the French Academy in France were formed. The goal of both organizations was the enhancement of pure and applied physics. And although enhancement of the military was not a major goal of either, it was no doubt a secondary goal.

Another important advance during this time, which no doubt helped Watt's steam engine, was a formulation of the fundamental gas law now known as Boyle's law. It states that the product of pressure and volume is constant for a given mass of confined gas, as long as the temperature is constant. This means, for example, that when the volume of the gas is halved, the pressure is doubled, or if the volume is doubled, the pressure is halved. It was first stated by Robert Boyle of England in 1662.

Watt's work, in turn, was critical to military development in that it made the production of both cannons and muskets much more efficient. Furthermore, as mentioned earlier, a major branch of physics, namely thermodynamics, was created as a result of Watt's work on the efficiency of engines.

Huygens's work on collisions and the centripetal force was also helpful in relation to the development of weapons of war, but it was his work on light, and his suggestion that light was a wave, which would eventually have tremendous implications. A few years later, with the work of Maxwell and Hertz, it would lead to the discovery of the electromagnetic spectrum, which would eventually have a very large impact on war.

And finally, Benjamin Robins's advances in gunnery were based primarily on physics, and they would dramatically change war over the next few decades.