The steam engine was too bulky to be used as a source of power for mechanically propelled road vehicles; what was needed was an engine that would combine the fire box, boiler, and cylinder of a steam plant in a small lightweight unit. The internal combustion engine, in which injected fuel mixed with air is exploded to drive the piston in a cylinder, proved to be the answer. It could supply more power per weight than a steam engine, and its moderate fuel consumption made long-distance travel not only possible but economical.

The evolution of the internal-combustion engine was conditioned by the increasing supply of cheap fuel and cheap steel. The supplies of gas or alcohol were too limited for a rapid development of the use of automobiles. It was then that petroleum entered the picture.

Colonel Drake had shown, beginning in 1859, how to produce crude oil in ever-increasing quantities from the deeper strata of the earth. The automobile was a boon to the oil refiners, for in the earlier days they had been forced to burn or throw away all light fractions that could not be used in lamp oil. But after 1900 gasoline production and hence the automobile too could develop freely.

Equally important for this development was the growing abundance of good, cheap steel in the latter half of the nineteenth century and the studies on the nature and combustion of gases, begun in the eighteenth and continued into the nineteenth century.

The earliest patent for a gas engine (as distinguished from a gasoline engine) was taken by Lebon in 1784, following his experiments in the production of gas. While Rivaz's gas engine of 1807 was a decided improvement, it was not until 1863 that the first practical gas engine with pre-ignition was designed by Lenoir. As early as 1838 Barnelt had constructed an engine using compression. Lenoir adopted this principle in a double-acting engine which he built into a vehicle that completed a successful trip of ten miles from Paris to Joinville-le-Pont.

The next important step was made by Marcus of Vienna in 1875, who constructed a slow four-stroke engine having magnetic ignition. Unfortunately, however, his engine was so noisy in operation that he was forbidden to make further experiments. When, therefore, in 1880 and 1881 several electric automobiles driven by Faure's accumulators made their appearance on Paris streets, it seemed for a time that the development of the engine would take a different turn.

Then in 1882 Daimler and Maybach started building the first practical gasoline engines. These were so compactly built that they were suitable for light vehicles, and attained speeds of up to 900 revolutions per minute. In 1885 one of these engines was mounted on a kind of wooden bicycle; then, the following year, on a four-wheeled carriage. The latter was the first automobile to complete successful trips through Cannstatt. At the same time Benz of Mannheim patented an automobile with a four-stroke engine and a body constructed of hollow tubing, giving a more suitable over-all weight in relation to the capacity of the engine. In America Charles E. Duryea demonstrated the first horseless carriages between 1891 and 1893.

These experiments drew great attention in France, where an automobile industry began to develop, using the patents of Benz and Daimler. In 1894 the first automobile races were held there. The winner achieved the incredible speed of fifteen miles per hour. The experimenting phase was over; the automobile was no longer a plaything or a freak. To use a well-worn phrase, it had come to stay.

Two important developments now took place, the first of which was the redesigning of the body and parts of the automobile. The older types had been true "horseless carriages," for they had been built along the lines of the earlier horse-drawn vehicles and still retained all their characteristics--for example, the higher back wheels, splashboard in front, open top and sides, and bench-type sear, under which the engine was placed. In 1901 Daimler produced the first car with a low body and forward engine, a vehicle really designed as a functional automobile. This was the Mercedes, and its design was soon followed by the Rolls-Royce in 1904. A windshield and a folding top were added to protect passengers from wind and rain. This materially added to the weight and wind resistance of the automobile, and spurred research into lighter, stronger bodies, which would overcome friction and wind resistance at higher speeds. The modern automobile tire, fashioned after the earlier Dunlop bicycle tire, was introduced in 1896 and greatly added to the absorption of shock and vibration while allowing lighter construction and greater speed, combined with better traction. The construction of the modern tire is due to Welch.

In 1896 Bosch built his low-voltage magneto, which was immediately applied to automobile ignition, together with his spark plug. The Daimler "honeycomb" radiator appeared about the same time and lent itself perfectly to later attempts at automobile streamlining. The earlier type of wheel was derived from the horse-driven carriage, but as a heavy type was needed, the gun-carriage wheel, invented in 1887, was usually adopted; although tangentially spiked wheels of the type used on bicycles were also employed for a short time. Then, in 1910, Rudge Witworth introduced his wire wheel with the hub so constructed that the wheel could be detached easily from the axle. During the period 1910-1935 the steel-spoke artillery type wheel was popular, until modem methods of pressing steel led to the introduction of the pressed-steel wheel that is in almost universal use on today's automobiles.

These improvements made possible large-scale introduction of the automobile. Early attempts at mass production date from 1899 to 1901, when the manufacture of the Opel, Horch, Adler, and Protos cars was started. By 1893 Henry Ford had constructed his first automobile, but it was not until 1903 that the first Ford car was introduced to a mass market with the founding of the Ford Motor Company at Dearborn, Michigan. This heralded the era of supremacy of American automotive production. At the same time a serious competitor of the gasoline engine appeared in the form of Rudolf Diesel's heavy-oil engine (1908-1909), which not only captured a large segment of bus transportation but was also used with great efficiency in locomotives and on ships.

The greatly increased use of the automobile during the First World War, which brought the tank in 1916, and other motor-driven engines of war, stimulated the use of trucks and automobiles in general. Not only did this extended use influence the design of modern roads, making them better able to handle the increasing number and heavier weight of motor vehicles, but it also built up a strong demand for cheaper and simpler cars having higher speeds. The First World War had shown the great importance of the introduction of standardized motor parts. Both standard parts and better organization of assembly formed the foundation of real mass production.

The earlier cars; as we have seen, had retained much of the design of the horse-driven carriage, but this now disappeared, and the so-called "touring car" with open sides and collapsible top gave place to the fully enclosed sedan or coupe. The enclosed car allowed for greater comfort as well as for adequate streamlining, which gave a more pleasing appearance whether or not it had much effect aerodynamically at ordinary legal speeds. At extremely high speeds the streamlining of the automobile does reduce fuel consumption, but under average conditions the greatest resistance is not from the air but from contact of the wheels with the ground. At any rate, streamlining and the manufacture of cheap standard parts were greatly assisted by the introduction of pressed steel, special steel alloys, and the use of aluminum alloys and molded plywood for the car body.

This second phase of mass production differed greatly from the first phase. Formerly the body and frame of the automobile was handmade, and the individual assembly of cars was the normal procedure. Now the conveyor system was applied to production, resulting in the familiar assembly line that has made possible the manufacture of more than four and a half million automobiles in a single year ( 1929), bringing a cheap form of transportation to millions of people and reshaping road traffic and road construction along entirely different lines. Ford, Morris, and Austin were among those who adopted these modern assembly methods in the early 1920's. . .