Around the turn of the third millenium, people thought about what a short
list of the most significant inventions of the second millenium
(1001-2000) would
necessarily entail...
Herb Brody (Technology Review senior editor) came up
with the following list, in chronological order:
compass, clock, lens, printing press, steam engine, telegraph,
electrical power, radio, antibiotics, and transistor.
That's just about it.
Improvements and applications of those great inventions were
ruled out, including the telephone, television, computer and other consumer electronics.
(So was the PN junction, which is overshadowed by its offspring, the transistor.)
The internal combustion engine did not make the list either,
because it is perceived as an improvement over the steam engine,
at least by nontechnical people.
However, the internal combustion engine is a radically new technical idea,
transcending fundamental limitations of steam engines.
Simply put, some chemical energy is directly put to work
in an internal combustion engine, whereas all of it is first transformed into heat
in a steam engine...
The fundamental difference is the push provided
by a chemical explosion.
The French have a better term for the internal combustion engine:
moteur à explosion.
To realize how important this is, you have to gain some exposure to the fundamentals
of steam engines, which were poorly understood for centuries, until
the theory of thermodynamics and its infamous
second law
were discovered.
The second law was first stated to explain the limited
efficiency of steam engines, but it ultimately explains
a lot more about the Universe around us and within us...
What follows is a guided tour through this fascinating history of
practical inventions and theoretical discoveries.
From water pumps to the elusive idea of entropy...
Heat Engines and the Fate of the Universe
(2004-02-15) The Aeolipile
Greatest ball of water wind and fire on Earth
The first documented steam engine was merely a toy.
It consisted of a boiler whose steam was routed through hollow supports
into a spherical chamber, which rotated on a polar axis as steam escaped from two
jet tubes along the equator.
This is described,
with many other pneumatic or hydraulic devices, in
Spiritalia seu Pneumatica by Hero / Heron of Alexandria (c.AD 10-75).
The term aeolipile
(French éolipyle, Latin
Aeoli pylae = ball of Aeolus)
may have been coined in the 17th century, when other engines appeared.
Some authors have attributed to an earlier prolific inventor called
Ctesibius
many of the contraptions described by Heron (who offers no clues on the matter).
The aeolipile may or may not
have been the work of Ctsibius.
Heron himself is much better known for the formula
named after him, which schoolchildren use to find the areas of scalene triangles.
(2005-06-26) Edward Somerset
of Worcester (c.1601-1667)
A blueprint for a steam-powered fountain (1662).
Edward Somerset was known as Lord Herbert after 1628.
In 1644, he became earl of Glamorgan, before inheriting the
title of sixth earl and second marquis of Worcester, in 1646.
Worcester published his design but apparently never built
an actual steam engine.
He proposed using the partial vacuum created when steam condenses
to obtain mechanical work from atmospheric pressure.
This was the key idea used by Newcomen in
his successful atmospheric engine, half a century later.
(2004-02-15) Denis Papin (1647-1712)
Beyond the pressure cooker: The first actual piston engine (1690).
The Frenchman Denis Papin invented the pressure cooker
A pressure cooker is a heated closed container.
Food cooks faster in it because the temperature of water can be
higher than the boiling point under ordinary atmospheric pressure.
A critical feature of the pressure cooker is, of course, its safety valve.
In 1690, Papin had the idea of fitting a piston over a boiler
with a limited amount of water in it.
When the boiler is heated, water becomes steam and the piston is
pushed upward.
When the boiler is allowed to cool, the steam condenses and atmospheric
pressure pushes the piston down, back to the original volume.
Although considerable forces can be involved, the power of Papin's engine is
low, because the heating and cooling of a single chamber is a
slow process.
(2005-06-25) Thomas Savery
(c.1650-1715): Separate Boiler
The Miner's Friend, Savery's two-piston steam engine (1698).
The English engineer Thomas Savery built an engine consisting
of two pistons over copper vessels which were alternately fed with steam
from a separate boiler.
This high-pressure engine could raise water about 20 feet (6 m).
Thomas Savery obtained several patents before
Thomas Newcomen made his own entrance.
(At some point, Savery may have employed Newcomen,
whose blacksmith shop was only
15 miles away from Savery's residence at Modbury.)
To put an end to the French Wars
of Religion, the newly-crowned (1589) King
Henri IV (1553-1610)
renounced his own Calvinist faith (1593)
and promulgated the Edict of Nantes
(13 April 1598) which granted civil rights and freedom of religion to
Huguenots in France.
This inaugurated a period of prosperity for which Henry IV was
celebrated
as one of the best-loved Kings of France. He was assassinated by a Catholic fanatic in 1610.
Two generations later,
Louis XIV became adamant about reverting
religious uniformity to his kingdom.
As financial incentives for conversions to Catholicism all but failed, he ressorted to
official persecutions,
through the practice of dragonnades.
Finally, Louis XIV infamously revoked the Edict of Nantes through the (second)
Edict of Fontainebleau (22 October 1685)
which ordered the destruction of Huguenot churches and the closing of all Protestant schools.
Enforcement did fade under the subsequent reign of Louis XV but legal headway wasn't made until Louis XVI signed the
Edict of Versailles (7 November 1787).
Freedom of religion was granted for good only by
Déclaration
des droits de l'homme et du citoyen (1789). Still current.
A law was passed on 15 December 1790 which offered French citizenship
to the descendants of all exiled Huguenots. It stayed in the books until 1945.
(Thus Mary Cartwright would have received French citizenship automatically if she
had bothered to claim it before 1945, because of her Huguenot ancestors.)
In 1985, France officially apologized to the descendants of Huguenots
and other victims of state persecutions.
Among the many French Hugenots who were exiled in the wake of the revocation
of the edict of Nantes, we find a few noted scientists:
Thomas Newcomen was an English blacksmith born in Dartmouth (Devonshire)
who set up shop there in 1685,
in partnership with a plumber named John Calley
[also spelled "Cawley"] (d.1717) who shared his interest in engines.
In 1698, Newcomen started corresponding with
Thomas Savery
and attempted to improve on Savery's machine to produce a safe and
reliable steam engine.
In 1708, Newcomen obtained a patent
(jointly with Savery)
for what's usually considered to be the
first practical
steam engine.
The use of low-pressure steam (5 psi) made it extremely safe.
The key idea was to spray cold water inside the piston's
chamber when is was filled with steam.
This caused steam to condense rapidly, and
the atmosphere pushed the piston back to a smaller volume.
In 1712, the first operational engine was built over
a mine near Dudley Castle.
It ran at 6 to 8 strokes per minute, with manual valves.
Automatic valves later allowed a typical regime of
10 to 12 rpm.
Newcomen's engine was successfully used to pump water from coal mines
throughout Europe. It was even exported to North America in 1755.
(2005-07-06) Nicolas Joseph Cugnot (1725-1804)
Le
Fardier de Cugnot was the first automobile (October 1769).
Joseph Cugnot was a French military engineer.
Ostensibly, he designed his fardier à vapeur
(steam dray) for the purpose of hauling artillery pieces.
The second prototype, which was completed by June 1771,
is religiously preserved in Paris, at the
Conservatoire National des Arts et Métiers.
(2004-02-15) James E. Watt (1736-1819)
The steam engine comes of age: Steam condenser
and governor.
The water-cooled steam condenser, patented by James Watt in 1769,
was the key to a dramatic improvement in the efficiency of steam engines.
Although the fundamental issue was not fully understood until 1824
(see Carnot's limit below)
this improved efficiency came from a greater temperature difference
[or ratio, rather] between active parts of the engine
throughout its cycle.
Watt's engine has two separate chambers:
The piston's cylinder remains at the temperature of
hot steam, while the steam condenser is water-cooled.
Among many other innovations,
Watt also introduced an ingenious speed regulator in 1788,
which is probably the earliest technological example of a
feedback mechanism:
The so-called Watt governor
(also known as the centrifugal or flyball governor)
made steam engines safer and easier to use.
By 1790, the new and improved Watt engines
had all but completely replaced Newcomen engines.
Watt's clever innovations were so successfull that it's now
necessary to stress that James Watt
did not invent the steam engine!
(2005-06-26) Richard Trevithick (1771-1833):
Steam Locomotive
The inventor of the railroad locomotive was not George Stephenson.
In 1796, Richard Trevithick
experimented with high-pressure noncondensing
steam engines and built his first miniature locomotive.
On Christmas eve of 1801, he took 7 of his friends
on a trip aboard a "road locomotive".
He is credited with the idea that smooth wheels on smooth
iron rails would provide enough traction for most practical purposes.
In February 1804, Trevithick tested the first locomotive ever to
run on rails.
This locomotive featured a single vertical cylinder, an 8-foot flywheel
and an innovative exhaust steam chimney
(producing an efficient updraft).
It hauled 5 wagons, 10 tons of iron and 70 passengers,
but made only 3 short trips on a projected 9-mile railroad
between the Merthyr-Cardiff Canal and the ironworks at Pen-y-darren
(whose owner, Samuel Homfray, was financing the enterprise).
Each time, the locomotive broke some cast-iron rails.
The sponsor gave up.
George Stephenson himself stressed the importance of the
experiments of Trevithick in the development of locomotives.
However, in February 1828, the House of Commons
denied a pension to Trevithick, who died in poverty.
The immediate successors to the Trevithick locomotives were used
in mining operations.
This included the Blutcher locomotive, built
in 1814 by the British engineer George Stephenson (1781-1848).
In 1829, the Liverpool and Manchester Railroad ran a
locomotive competition for a railway intended to carry both passengers and freight.
The trials took place at Rainhill, near Liverpool, in October 1829.
The award went to Stephenson, for a legendary locomotive named
Rocket.
(2005-06-23) Sadi Carnot (1796-1832):
The Carnot Cycle
Fundamental limitations:
The second law of thermodynamics.
After the dramatic innovations of James Watt, many engineers wondered
if anything could be done to further increase the low efficiency
of steam engines.
By offering a sobering upper limit to that efficiency,
a young Frenchman helped create the new science of thermodynamics:
In 1824, [Nicolas Léonard] Sadi Carnot analyzed an ideal engine
transforming into work some of the heat going from a hot source to a cold one...
Carnot defined the efficiency of an heat engine
as the ratio of the net work done
by the engine to the heat it received from its boiler
(whatever heat is spend by the engine to warm up the condenser is,
indeed, pure waste).
This efficiency can't exceed the following function of the hot
(T1 ) and cold (T0 )
temperatures above absolute zero, known as Carnot's limit :
1 -
T0 / T1
The unavoidable "waste" is thus equal to the ratio of the absolute temperatures.
This example was ultimately generalized into what became the
Second Law of Thermodynamics, even
before the First Law was generally accepted.
Carnot's limit is not directly applicable to an internal
combustion engine, which may involve some direct transformation
of chemical energy into mechanical work.
(2005-06-22) Sir Charles Algernon
Parsons (1854-1931)
Steam turbines (1884) are still used in nuclear power plants.
In 1629, Italian engineer Giovanni Branca (1571-1640) ran
a double-pestle stamp mill with a steam blower
(directing a jet to vanes on a wheel).
In 1791, the British inventor John Barber obtained a patent for a gas turbine.
In 1884, Charles Parsons (6th son of the 3rd earl of Rosse)
patented the modern steam turbine, with multiple staging.
Each stage in such a turbine improves overall efficiency by making
use of the steam of the previous stage and is optimized for its
task in this chain of successively lower steam pressures.
Parsons' first prototype produced about 10 hp
at 20000 rpm (by contrast, a reciprocating steam engine is
limited to about 1500 rpm, at best).
In 1887, the Swedish engineer
Carl Gustaf Patrik de Laval (1845-1913)
built a small demonstration steam turbine which rotated at 42000 rpm.
In 1890, he invented the convergent-divergent nozzle now named after him,
to optimize the efficiency of a single-stage steam turbine
(the de Laval nozzle is commonly used in modern rocketry).
De Laval also came up with innovative reduction gearing which could
accomodate the high rotational speed of steam turbines.
De Laval was an inventor of the same caliber as Thomas Edison.
He described his inventions meticulously in over 1000 diaries.
In the 1890s, he employed over 100 engineers to put them to good use.
Turbinia :
Although he had no training as a naval architect, Parsons designed and built
Turbinia,
the first ship ever to be powered by steam turbines.
He demonstrated her astounding speed on June 22, 1897, during
Queen Victoria's Diamond Jubilee Fleet Review.
Parsons piloted the ship himself, at the astounding speed of 34.5 knots
(64 km/h, 40 mph).
Charles Parsons was knighted in 1911.
(2011-08-31) The Drinking Bird
( insatiable birdie )
A clever heat engine based on evaporative cooling.
The very popular book "Physics for Entertainment" by
Yakov Perelman (1882-1942)
was first published in 1913 and was last revised by its original author in 1936.
It went through 18 Russian editions before
being translated in English (in 1975, volume 2 only).
On pp. 226-228 of that translation,
the insatiable birdie is discussed as an interesting "Chinese toy"
(its exact origin is unknown, to the best of my knowledge).
The drinking bird was
patented in the US by Miles V. Sullivan in 1946.
The son of Miles Sullivan has confirmed that Albert
Einstein could not figure out the operating principle of the toy when he was
first confronted with it (in 1922). Neither could most physicists...
The fluid contained in the vessel (which is usually colored)
must have a fairly high vapor pressure at room
temperature. The US patent (1946) mentions
"ether,
alcohol,
carbon tetrachloride or
chloroform".
Formerly, the toy was manufactured with
trichloromonofluoromethane
(Freon-11) before its harmful impact on the environment was recognized.
Nowadays, dichloromethane is
most commonly used (it's a moderately hazardous substance heralded as
the least toxic of the simple
organochlorides).
Homer Simpson
