The productivity-improving technologies are the technological innovations that have historically increased productivity.

Productivity is often measured as the ratio of (aggregate) output to (aggregate) input in the production of goods and services. Sickles, R., & Zelenyuk, V. (2019). Measurement of Productivity and Efficiency: Theory and Practice. Cambridge: Cambridge University Press. doi:10.1017/9781139565981 Productivity is increased by lowering the amount of labor, capital, energy or materials that go into producing any given amount of economic goods and services. Increases in productivity are largely responsible for the increase in per capita living standards.

History

Productivity-improving technologies date back to antiquity, with rather slow progress until the late Middle Ages. Important examples of early to medieval European technology include the water wheel, the horse collar, the spinning wheel, the crop rotation systems (the three-field system and, after 1500, the four-field system) and the blast furnace.

Technological progress was aided by literacy and the diffusion of knowledge that accelerated after the spinning wheel spread to Western Europe in the 13th century. The spinning wheel increased the supply of rags used for pulp in paper making, whose technology reached Sicily sometime in the 12th century. Cheap paper was a factor in the development of the movable type printing press, which led to a large increase in the number of books and titles published. Books on science and technology eventually began to appear, such as the mining technical manual De Re Metallica, which was the most important technology book of the 16th century and was the standard chemistry text for the next 180 years.

Francis Bacon (1561–1626) is known for the scientific method, which was a key factor in the Scientific Revolution. Bacon stated that the technologies that distinguished Europe of his day from the Middle Ages were paper and printing, gunpowder and the magnetic compass, known as the Four Great Inventions, which had origins in China. Other Chinese inventions included the horse collar, cast iron, an improved plow and the seed drill.

Mining and metal refining technologies played a key role in technological progress. Much of our understanding of fundamental chemistry evolved from ore smelting and refining, with De re metallica being the leading chemistry text. Railroads evolved from mine carts and the first steam engines were designed specifically for pumping water from mines. The significance of the blast furnace goes far beyond its capacity for large scale production of cast iron. The blast furnace was the first example of continuous production and is a countercurrent exchange process, various types of which are also used today in chemical and petroleum refining. Hot blast, which recycled what would have otherwise been waste heat, was one of engineering's key technologies. It had the immediate effect of dramatically reducing the energy required to produce pig iron, but reuse of heat was eventually applied to a variety of industries, particularly steam boilers, chemicals, petroleum refining and pulp and paper.

Before the 17th century scientific knowledge tended to stay within the intellectual community, but by this time it became accessible to the public in what is called "open science". Near the beginning of the Industrial Revolution came publication of the Encyclopédie, written by numerous contributors and edited by Denis Diderot and Jean le Rond d'Alembert (1751–72). It contained many articles on science and was the first general encyclopedia to provide in depth coverage on the mechanical arts, but is far more recognized for its presentation of thoughts of the Enlightenment.

Economic historians generally agree that, with certain exceptions such as the steam engine, there is no strong linkage between the 17th century scientific revolution (Descartes, Newton, etc.) and the Industrial Revolution. However, an important mechanism for the transfer of technical knowledge was scientific societies, such as The Royal Society of London for Improving Natural Knowledge, better known as the Royal Society, and the Académie des Sciences. There were also technical colleges, such as the École Polytechnique. Scotland was the first place where science was taught (in the 18th century) and was where Joseph Black discovered heat capacity and latent heat and where his friend James Watt used knowledge of heat to conceive the separate condenser as a means to improve the efficiency of the steam engine.

Probably the first period in history in which economic progress was observable after one generation was during the British Agricultural Revolution in the 18th century.Mark Overton: Agricultural Revolution in England 1500–1850 (2011) However, technological and economic progress did not proceed at a significant rate until the English Industrial Revolution in the late 18th century, and even then productivity grew about 0.5% annually. High productivity growth began during the late 19th century in what is sometimes called the Second Industrial Revolution. Most major innovations of the Second Industrial Revolution were based on the modern scientific understanding of chemistry, electromagnetic theory and thermodynamics and other principles known to the profession of engineering.

Major sources of productivity growth in economic history

New forms of energy and power Before the industrial revolution the only sources of power were water, wind and muscle. Most good water power sites (those not requiring massive modern dams) in Europe were developed during the medieval period. In the 1750s John Smeaton, the "father of civil engineering," significantly improved the efficiency of the water wheel by applying scientific principles, thereby adding badly needed power for the Industrial Revolution. However water wheels remained costly, relatively inefficient and not well suited to very large power dams. Benoît Fourneyron's highly efficient turbine developed in the late 1820s eventually replaced waterwheels. Fourneyron type turbines can operate at 95% efficiency and used in today's large hydro-power installations. Hydro-power continued to be the leading source of industrial power in the United States until past the mid 19th century because of abundant sites, but steam power overtook water power in the UK decades earlier.

In 1711 a Newcomen steam engine was installed for pumping water from a mine, a job that typically was done by large teams of horses, of which some mines used as many as 500. Animals convert feed to work at an efficiency of about 5%, but while this was much more than the less than 1% efficiency of the early Newcomen engine, in coal mines there was low quality coal with little market value available. Fossil fuel energy first exceeded all animal and water power in 1870. The role energy and machines replacing physical work is discussed in Ayres-Warr (2004, 2009).

While steamboats were used in some areas, as recently as the late 19th Century thousands of workers pulled barges. Until the late 19th century most coal and other minerals were mined with picks and shovels and crops were harvested and grain threshed using animal power or by hand. Heavy loads like 382 pound bales of cotton were handled on hand trucks until the early 20th century.

Excavation was done with shovels until the late 19th century when steam shovels came into use. It was reported that a laborer on the western division of the Erie Canal was expected to dig 5 cubic yards per day in 1860; however, by 1890 only 3-1/2 yards per day were expected. Today's large electric shovels have buckets that can hold 168 cubic meters (220 cubic yards) and consume the power of a city of 100,000.

Dynamite, a safe to handle blend of nitroglycerin and diatomaceous earth was patented in 1867 by Alfred Nobel. Dynamite increased productivity of mining, tunneling, road building, construction and demolition and made projects such as the Panama Canal possible.

Steam power was applied to threshing machines in the late 19th century. There were steam engines that moved around on wheels under their own power that were used for supplying temporary power to stationary farm equipment such as threshing machines. These were called road engines, and Henry Ford seeing one as a boy was inspired to build an automobile. Steam tractors were used but never became popular.

With internal combustion came the first mass-produced tractors (Fordson ). Tractors replaced horses and mules for pulling reapers and combine harvesters, but in the 1930s self powered combines were developed. Output per man hour in growing wheat rose by a factor of about 10 from the end of World War II until about 1985, largely because of powered machinery, but also because of increased crop yields. Corn manpower showed a similar but higher productivity increase.

One of the greatest periods of productivity growth coincided with the electrification of factories which took place between 1900 and 1930 in the U.S.

Energy efficiency In engineering and economic history the most important types of energy efficiency were in the conversion of heat to work, the reuse of heat and the reduction of friction. There was also a dramatic reduction energy required to transmit electronic signals, both voice and data.

Conversion of heat to work

The early Newcomen steam engine was about 0.5% efficient and was improved to slightly over 1% by John Smeaton before Watt's improvements, which increased thermal efficiency to 2%. In 1900, it took 7 lbs coal/ kw hr.

Electrical generation was the sector with the highest productivity growth in the U.S. in the early twentieth century. After the turn of the century large central stations with high pressure boilers and efficient steam turbines replaced reciprocating steam engines and by 1960 it took 0.9 lb coal per kw-hr. Counting the improvements in mining and transportation the total improvement was by a factor greater than 10. Today's steam turbines have efficiencies in the 40% range.Robert U. Ayres and Benjamin Warr, The Economic Growth Engine: How useful work creates material prosperity, 2009. Graph of steam engine efficiencies Most electricity today is produced by thermal power stations using steam turbines.

The Newcomen and Watt engines operated near atmospheric pressure and used atmospheric pressure, in the form of a vacuum caused by condensing steam, to do work. Higher pressure engines were light enough, and efficient enough to be used for powering ships and locomotives. Multiple expansion (multi-stage) engines were developed in the 1870s and were efficient enough for the first time to allow ships to carry more freight than coal, leading to great increases in international trade.

The first important diesel ship was the MS Selandia launched in 1912. By 1950 one-third of merchant shipping was diesel powered. Today the most efficient prime mover is the two stroke marine diesel engine developed in the 1920s, now ranging in size to over 100,000 horsepower with a thermal efficiency of 50%.

Steam locomotives that used up to 20% of the U.S. coal production were replaced by diesel locomotives after World War II, saving a great deal of energy and reducing manpower for handling coal, boiler water and mechanical maintenance.

Improvements in steam engine efficiency caused a large increase in the number of steam engines and the amount of coal used, as noted by William Stanley Jevons in The Coal Question. This is called the Jevons paradox.

Electrification and the pre-electric transmission of power

Electricity consumption and economic growth are strongly correlated. <Available as free .pdf download> Per capita electric consumption correlates almost perfectly with economic development.