In this post I will look at one of the major threads of technological development in the past 150 years.
THE MASS PRODUCED, OIL FUELED, INTERNAL COMBUSTION ENGINE
All three parts of that title are important. The importance of the internal combustion engine (ICE) is that it would provide a convenient drive for mobile machinery. It is a heat engine, as the steam engine is. This means that heat goes in and mechanical work comes out. The heat comes from burning fossil fuels in both cases, but because the internal combustion engine burns fuel inside its cylinders that fuel must be ash-free. That's a problem, because it can't use coal, and the 19th century ran on coal.
If it is going to be mobile, the ICE needs a fuel that is easy to store and ash free. That means a liquid organic compound like ethanol or vegetable oil or gasoline. The ICE would never have succeeded if the oil industry had not been able to provide it with vast amounts of fuel.
For the ICE to really change the world it needed to be cheap enough for everybody to own one. That's why mass production is important. Part of mass production is the use of interchangeable parts. We take that for granted today, but it presented challenges in the 19th century. Before interchangeable parts became common, everything was custom-built.
Another really important part of mass production is the assembly line. This was perfected by the Ford Motor Company in 1914 for the assembly of their Model T automobile. It provided an eightfold productivity boost. It also eliminated the use of skilled labor in direct production. One advantage noted by Henry Ford was that no special training was required for the workforce, and that anyone could do the work.
In the chart below I look at the impact of the ICE over time.
One of the most significant applications was the mechanization of farms. Farming's share of the American workforce fell by 37 percentage points. This may have accounted for about a quarter of the total progress 1880-1970. It is likely that many former agricultural workers found employment on assembly lines, which did not require skilled labor.
The development of mass production techniques and the development of the assembly line provided huge productivity boosts. The assembly line for the Ford Model T, started up in 1914, increased labor productivity by a factor of eight. The electrification of factories also delivered significant gains. Before electricity factory machinery was driven by a system of shafts and belts. Electricity allowed factories to be reorganized. Henry Ford reckoned that electric motors doubled productivity.
Mass produced automobiles enabled the development of spread out car dependent suburbs such as Levittown. The builders of these suburbs adopted mass production techniques as far as possible to drive down costs.The increased living space provided room for more consumer items.
Meanwhile, the development of airplanes increased long distance transportation speeds. Transatlantic crossing time fell from 4 days by ship to 29 hours by air when the first air service was launched. Jet powered passenger planes later reduced that to 7 hours. On the ground, the interstate highway system increased the speed and flexibility of land transportation.