Lecture 20 min.
By the end of the 19th century, the "Age of Electricity" had arrived. While the first machines had been built by self-taught craftsmen, science now played a decisive role in people's lives — the spread of electric motors was a direct result of scientific progress. The "Age of Electricity" began with the invention of the dynamo, a direct-current generator built by the Belgian engineer Zénobe Gramme in 1870. Owing to the principle of reversibility, the Gramme machine could work either as a generator or as a motor, and it could easily be converted into an alternating-current generator. In the 1880s, the Serbian-born Nikola Tesla, working in America for the Westinghouse Electric company, created a two-phase alternating-current motor. At the same time, the Russian electrical engineer Mikhail Dolivo-Dobrovolsky, working in Germany for AEG, created an efficient three-phase electric motor. The task of harnessing electric power now came down to the problem of transmitting current over long distances. In 1891, the World's Fair opened in Frankfurt. Commissioned by the fair's organizers, Dolivo-Dobrovolsky built the first high-voltage power line and a transformer to go with it; the deadline set by the order was so tight that no tests were carried out at all — the system was switched on and worked immediately. After this exhibition, Dolivo-Dobrovolsky became the leading electrical engineer of his day, and AEG became the largest manufacturer of electrical equipment. From this time on, factories and mills began switching from steam engines to electric motors, and large power plants and transmission lines sprang up.
A major achievement of electrical engineering was the creation of the electric lamp. The American inventor Thomas Edison took up this task in 1879; his staff carried out more than 6,000 experiments testing various materials for the filament, and bamboo fiber turned out to be the best material — so Edison's first light bulbs were "bamboo" bulbs. Only twenty years later, at the suggestion of the Russian engineer Lodygin, did filaments begin to be made of tungsten.
Power plants required engines of very great power, and this problem was solved by the creation of the steam turbine. In 1889, the Swede Gustaf de Laval received a patent for a turbine in which the steam outflow velocity reached 770 meters per second. At the same time, the Englishman Charles Parsons created a multistage turbine; the Parsons turbine came to be used not only in power plants but also as an engine for fast ships, cruisers, and ocean liners. Hydroelectric power plants also appeared, using hydraulic turbines developed in the 1830s by the French engineer Benoît Fourneyron. In 1884, the American Lester Pelton patented a jet turbine that operated under high pressure. Hydraulic turbines had a very high efficiency, on the order of 80 percent, and the energy produced by hydroelectric plants was very cheap.
Alongside the work on building ever more powerful engines, work was also underway on small, portable engines. At first these were gas engines running on illuminating gas, intended for small enterprises and craft workshops. The gas engine was an internal combustion engine, meaning that fuel was burned directly inside the cylinder and the combustion products drove the piston. Operating at high temperatures inside the cylinder required a cooling and lubrication system; these problems were solved by the Belgian engineer Étienne Lenoir, who built the first gas engine in 1860.
However, illuminating gas made from wood shavings was an expensive fuel, and far more promising was the work on engines running on gasoline. The gasoline engine required the invention of the carburetor, a device for atomizing fuel inside the cylinder. The first workable gasoline engine was built in 1883 by the German engineer Julius Daimler. This engine opened the era of the automobile; already in 1886 Daimler installed his engine on a four-wheeled carriage. This machine was shown at an exhibition in Paris, where the French manufacturers René Panhard and Étienne Levassor bought a license to produce it. Panhard and Levassor used only Daimler's engine; they built their own car, fitting it with a clutch, a gearbox, and rubber tires. This was the first true automobile, and in 1894 it won the first automobile race, Paris–Rouen. The following year, Levassor won the Paris–Bordeaux race in his car. "It was madness!" the winner said. "I was racing at 30 kilometers an hour!" Daimler himself, however, decided to go into automobile production; in 1890 he founded the company Daimler Motoren, and ten years later this company released the first car under the Mercedes brand. The Mercedes became the classic automobile of the early 20th century; it had a four-cylinder, 35-horsepower engine and reached a speed of 70 kilometers per hour. This beautiful and reliable machine was an enormous success and marked the beginning of mass automobile production.
The efficiency of the Daimler engine was about 20 percent, while that of steam engines did not exceed 13 percent. Yet according to the theory of heat engines developed by the French physicist Carnot, the efficiency of an ideal engine could reach 80 percent. The idea of an ideal engine excited the minds of many inventors, and in the early 1890s the young German engineer Rudolf Diesel attempted to bring it to life. Diesel's idea was to compress air inside the cylinder to a pressure of about 90 atmospheres, at which the temperature reached 900 degrees; fuel was then injected into the cylinder, giving the engine's working cycle a form close to the ideal "Carnot cycle." Diesel was not able to fully realize his idea; because of technical difficulties, he was forced to lower the cylinder pressure to 35 atmospheres. Nevertheless, the first Diesel engine, which appeared in 1895, caused a sensation — its efficiency was 36 percent, twice that of gasoline engines. Many firms sought to buy a license to produce the engines, and by 1898 Diesel had already become a millionaire. However, producing these engines demanded a high level of manufacturing skill, and for many years Diesel had to travel from country to country setting up production of his engines.
The internal combustion engine was used not only in automobiles. In 1901 the American engineers Hart and Parr built the first tractor; in 1912 the Holt company began producing tracked tractors, and by 1920 some 200,000 tractors were working on American farms. The tractor took over not only fieldwork — its engine was also used to drive threshers, mowers, mills, and other agricultural machines. The creation of the tractor marked the beginning of the mass mechanization of agriculture.
The appearance of the internal combustion engine played a major role in the birth of aviation. At first it was thought enough to mount an engine on a winged craft for it to rise into the air. In 1894 the famous inventor of the machine gun, Maxim, built an enormous airplane with a wingspan of 32 meters and a weight of 3.5 tons — this machine crashed on its very first attempt to take off. It turned out that the main problem of flight was stability. This problem was solved through long experimentation with models and gliders. Back in the 1870s, the Frenchman Pénaud built several small models driven by a rubber motor; his experiments led to the conclusion that the tail assembly played an important role. In the 1890s, the German Otto Lilienthal made about 2,000 flights on a glider of his own design. He steered the glider by shifting the balance of his body and could stay airborne for up to 30 seconds, covering 100 meters in that time. Lilienthal's experiments ended in tragedy: he could not cope with a gust of wind and crashed after falling from a height of 15 meters. The work of building gliders was carried on by the American Wright brothers, owners of a bicycle repair shop in the city of Dayton. The Wright brothers introduced a vertical rudder and lateral control surfaces — ailerons — and measured the lift force of wings using an airflow tunnel of their own invention. The glider built by the Wright brothers was well controlled and could stay in the air for about a minute. In 1903 the Wright brothers fitted the glider with a small gasoline engine, which they built themselves in their own workshop. On December 14, 1903, Wilbur Wright made the first powered flight, covering 32 meters; on December 17, the flight distance reached 260 meters. These were the first flights in the world — before the Wright brothers, no airplane had ever managed to get airborne. Gradually increasing the power of the engine, the Wright brothers learned to fly their airplane; in October 1905 the plane stayed aloft for 38 minutes, covering 39 kilometers while flying in a circle. Yet the Wright brothers' achievements went unnoticed, and their appeals to the government for support went unanswered. In that same year, 1905, lack of funds forced the Wright brothers to stop their flights. In 1907 the Wrights visited France, where the public took a great interest in the flights of the first aviators — although the range of the French aviators' flights was measured only in hundreds of meters, and their airplanes had no ailerons. The Wright brothers' accounts and photographs caused such a sensation in France that the echo of it reached America, and the government promptly awarded the Wrights a contract worth 100,000 dollars. In 1908 the Wrights' new airplane made a flight lasting 2.5 hours. Orders for airplanes poured in from every side, and the Wright Company, an aircraft manufacturing firm with a capital of 1 million dollars, was founded in New York. But already in 1909 several crashes involving "Wright" machines occurred, and disillusionment set in. The reason was that the Wright brothers' airplanes had no tail assembly, and so they often "nosed over." The French aviators knew of the need for a tail assembly from Pénaud's experiments; they soon borrowed ailerons from the Wright brothers and surpassed their American counterparts. In 1909 Louis Blériot flew across the English Channel. That same year Henri Farman created the first mass-produced airplane model, the famous "Farman III." This airplane became the principal training machine of its time and the first airplane to go into serial production.
At the end of the 19th century, work continued on new means of communication, and the telegraph gave way to the telephone and radio. The first experiments in transmitting speech over distance were carried out by the English inventor Reis in the 1860s. In the 1870s these experiments attracted the interest of Alexander Bell, a Scotsman who had emigrated to America and taught first at a school for deaf children and later at Boston University. A physician he knew suggested that Bell use a human ear for his experiments and brought him an ear taken from a corpse. Bell copied the eardrum, and by placing a metal membrane next to an electromagnet, he achieved satisfactory transmission of speech over short distances. In 1876 Bell took out a patent for the telephone and sold more than 800 units that same year. The following year David Hughes invented the microphone, and Edison applied the transformer to transmit sound over long distances. In 1877 the first telephone exchange was built, Bell founded a company to manufacture telephones, and ten years later there were already 100,000 telephones in the United States.
While working on the telephone, Edison had the idea of recording the vibrations of the microphone's membrane. He fitted the membrane with a needle that recorded the vibrations onto a foil-covered cylinder. This is how the phonograph came about. In 1887 the American Emile Berliner replaced the cylinder with a flat disc and created the gramophone. Gramophone records could easily be copied, and soon a great many companies engaged in sound recording sprang up.
A new step in the development of communications was taken with the invention of the radiotelegraph. The scientific foundation of radio communication was the theory of electromagnetic waves developed by Maxwell. In 1886 Heinrich Hertz experimentally confirmed the existence of these waves using a device called an oscillator. In 1891 the French physicist Branly discovered that metal filings placed in a glass tube changed their resistance under the action of electromagnetic waves. This device came to be called the coherer. In 1894 the English physicist Lodge used the coherer to detect the passage of waves, and the following year the Russian engineer Alexander Popov attached an antenna to the coherer and adapted it to receive signals emitted by Hertz's oscillator. In March 1896 Popov demonstrated his apparatus at a meeting of the Russian Physico-Chemical Society and transmitted signals over a distance of 250 meters. At the same time as Popov, the young Italian Guglielmo Marconi built his own radiotelegraph apparatus; he was the first to succeed in patenting the invention, and the following year he organized a joint-stock company to exploit it. In 1898 Marconi added a "jigger" — a device for amplifying antenna currents — to his receiver, which made it possible to increase the transmission range to 85 miles and to achieve transmission across the English Channel. In 1900 Marconi replaced the coherer with a magnetic detector and achieved radio communication across the Atlantic Ocean: President Roosevelt and King Edward VIII exchanged greeting telegrams by radio. In October 1907 the Marconi company opened the first radiotelegraph station for the general public.
One of the remarkable achievements of this period was the creation of cinema. The emergence of motion pictures was directly linked to improvements in the photographic process invented by Daguerre. In 1871 the Englishman Maddox developed the dry gelatin-bromide process, which reduced exposure time to 1/200 of a second. In 1877 the Pole Leon Warnerke invented a roll-film camera using bromide-silver paper film. In 1888 the German photographer Anschütz created the instantaneous focal-plane shutter. This made it possible to take instantaneous snapshots, and the whole problem then came down to creating an intermittent mechanism capable of taking pictures at intervals of a fraction of a second. This mechanism, along with the first movie camera, was created by the Lumière brothers in 1895. In December of that year the first cinema opened on the Boulevard des Capucines in Paris. In 1896 the Lumières toured all the capitals of Europe demonstrating their first film; this tour was an enormous success.
At the end of the 19th century, substances now known as plastics were created for the first time. In 1873 celluloid — the first such substance to come into widespread use — was patented by J. Hyatt of the United States. Before the First World War, Bakelite and other plastics, known collectively as phenolic resins, were invented. The production of artificial fiber began after the French engineer G. Chardonnet developed a method for producing nitro-silk in 1884; artificial silk was later produced from viscose as well. In 1899 the Russian scientist I. L. Kondakov laid the foundation for the production of synthetic rubber.
The last decades of the 19th century were a time of technical change in construction. The building of high-rise structures, which came to be called "skyscrapers," began in Chicago in the 1880s. The first building of the new type is considered to be the 10-story building of a Chicago insurance company, built in 1883 by the architect W. Jenney, who used steel floor framing. Reinforcing the walls with a steel frame, which took on the load of the floor beams, made it possible to double the height of buildings. The tallest building of its time was a 58-story New York skyscraper, 228 meters high, built in 1913. But the tallest structure of all was the Eiffel Tower, a kind of monument to the "age of steel." Erected by the French engineer Gustave Eiffel on the Champ de Mars in Paris for the World's Fair of 1889, this lattice tower stood 300 meters high.
Alongside steel structures, reinforced concrete structures also came into wide use during this period. The man credited with discovering reinforced concrete is the French gardener Joseph Monier. As early as 1849 he made planting tubs for fruit trees with a frame of iron wire. Continuing his experiments, in the 1860s he patented several methods for making pipes, tanks, and slabs from concrete with iron reinforcement. The most important of his patents was for reinforced concrete vaulted ceilings (1877).
The end of the 19th century was a time of explosive growth in the world's railway network. Between 1875 and 1917 the total length of railways grew fourfold, reaching 1.2 million kilometers. Famous construction projects of the time included the Berlin–Baghdad railway and the Trans-Siberian Railway; the length of the Siberian route reached 7,400 kilometers by 1916. Steel rails were laid on the new railways, which crossed the world's greatest rivers, and gigantic steel bridges were built over these rivers. The "age of steel bridges," as contemporaries called it, began with the arch bridge built by the engineer J. Eads over the Mississippi River (1874) and the suspension Brooklyn Bridge, designed by the architect Roebling, in New York (1883). The central span of the Brooklyn Bridge was about half a kilometer long. Powerful compound locomotives, with multiple expansion and highly superheated steam, worked on the new railways. In the 1890s the first electric locomotives and electrified railways appeared in the United States and Germany.
The construction of railways required a manifold increase in steel production. Between 1870 and 1900 steel output grew seventeenfold. In 1878 the English engineer S. G. Thomas introduced the Thomas process for converting pig iron into steel; this process made it possible to use the phosphoric iron ores of Lorraine and supplied ore to the German metallurgical industry. In 1892 the French chemist H. Moissan created the electric arc furnace. In 1888 the American engineer C. M. Hall developed an electrolytic process for producing aluminum, opening the way to the widespread industrial use of aluminum.
New technical capabilities led to improvements in military technology. In 1887 the American Hiram Maxim built the first machine gun. The famous Maxim gun fired 400 rounds a minute and was equal in firepower to a company of soldiers. Rapid-firing three-inch guns and heavy 12-inch cannon firing shells weighing 200–300 kg appeared.
The changes in naval warship construction were especially striking. The Crimean War (1853–1856) still involved giant wooden sailing ships carrying hundreds of guns on three gun decks, and the heaviest shells of the time weighed 30 kg. In 1860 England launched the first iron ironclad, the "Warrior," and soon all wooden warships were scrapped. A naval arms race began, with England and France competing to build ever more powerful ironclads; Germany and the United States later joined this race. In 1881 the English ironclad "Inflexible" was built, with a displacement of 12,000 tons; it had only 4 main-caliber guns, but these were colossal 16-inch guns mounted in rotating turrets, with a barrel length of 8 meters and a shell weight of 700 kg. Before long, all the leading naval powers began building ironclads of this type (though mostly with 12-inch guns). A new stage in the arms race was triggered by the appearance in 1906 of the English battleship "Dreadnought"; the Dreadnought had a displacement of 18,000 tons and ten 12-inch guns. Thanks to its steam turbine, it reached a speed of 21 knots. Faced with the Dreadnought's power, all earlier ironclads became obsolete, and the naval powers began building ships like the Dreadnought. In 1913 battleships of the "Queen Elizabeth" class appeared, with a displacement of 27,000 tons and ten 15-inch guns. This arms race led, in the natural course of things, to a world war.
The cause of the world war was the mismatch between the real power of the European states and the size of their possessions. England, taking advantage of its role as leader of the Industrial Revolution, had built a vast colonial empire and seized most of the resources needed by other countries. By the end of the 19th century, however, Germany had become the leader in technical and industrial development; naturally, Germany sought to use its military and technical superiority to bring about a new division of the world. In 1914 the First World War began. The German high command hoped to crush its opponents within a couple of months, but these calculations failed to account for the role of a new weapon that had just appeared — the machine gun. The machine gun gave a decisive advantage to the defending side; the German offensive was halted and a long "trench war" began. Meanwhile, the English fleet blockaded German ports and cut off food supplies. In 1916 famine began in Germany, which ultimately led to the collapse of the home front, to revolution, and to Germany's defeat.
Comments