Why do historians distinguish two Industrial revolutions, instead of just one?
We are actually entering into the 4th Industrial revolution.
The first industrial revolution was defined by new ideas on how to organize labor which had a profound effect on manufacturing efficiency.
division of labor -> productivity -> trade -> need for free markets -> new ideas on how nations measure wealth and handle industrial competition.
Rather than have an individual master craftsman produce a product, production was broken down into component tasks and then specialized labor was employed to perform each sub-task in tandem. Wages went down. skill of workers went down. efficiency went up by orders of magnitude. This upended the old master apprentice guilds and turned manufacturing from a subsistence endeavor into one which commanded great wealth for the owner of the now concentrated manufacturing endeavor. Now instead of each town requiring a specialized craftsman to produce a widget a single town employing largely unskilled/ or lower skilled workers could provide all the widgets a town, country, or multiple countries would require. Leading to the need for increased international trade and new beliefs on how countries should react to foreign manufacturing displacing local production (free markets)...
During this time Adam Smith wrote Wealth of Nations**, basically creating the field of economics, documenting the lessons learned from this, the first Industrial revolution.
The Wealth of Nations or An Inquiry into the Nature and Causes of the Wealth of Nations
- Book I: Of the Causes of Improvement in the productive Powers of Labour
- Book II: Of the Nature, Accumulation, and Employment of Stock
- Book III: Of the different Progress of Opulence in different Nations
- Long-term economic growth
- Agricultural jobs
- Book IV: Of Systems of political Economy
- Book V: Of the Revenue of the Sovereign or Commonwealth
Many different lessons but the one which is important for this question is that wealth of a nation was not defined by how much gold they possessed but rather what they manufactured. Wealth and prosperity Smith said was dependent on how a country spent the profits from the new more efficient manufacturing processes. Countries which were able to re-invest their profits into continuously improving their manufacturing would grow, those which did not would fall behind those who did, loose market share, and ultimately be replaced. So from this (Adam Smith's 1776 perspective) all 4 industrial revolutions are natural progressions of the first. All falling out of Smith's idea on constantly increasing production, or THE Industrial Revolution.
The case for breaking them apart is made following the same rational for naming the first. When a new technology or idea dramatically changes manufacturing we deem it a new Industrial Revolution, as specialization of labor and continuous improving of manufacturing first dramatically changed manufacturing efficiency in the 18th century. Jobs change, architecture change, labor patterns the entire fabric of industrialized countries change.
What were these other re-ordering technologies/ideas?
The Second Industrial Revolution is defined by automation and steel. Automation by incorporating new energy sources such as coal and electricity which were more efficient and less labor intensive than wood. Energy for manufacturing production became more efficient, portable, cheaper, and scale-able. These new industrial energy sources along with the Bessemer process (patented 1856) for manufacturing steel is what defines the second Industrial Revolution. The Bessemer process was the first industrial process for manufacturing steel. It did for steel what the first Industrial Revolution did for other products. Making steel cheap, plentiful and more widely used throughout the economy. This allowed stronger lighter steel to replace iron in manufacturing. Fueled new architectures (taller buildings / high rises, even sky scrappers), equipment and technologies. Faster lighter trains, safer stronger bridges, etc..
Andrew Carnegie's Keystone Bridge Company began the Eads Bridge in 1867 in St. Louis (completed in 1874). It would be the first bridge across the Mississippi River. Due to the swift currents and the width of the river an iron bridge was unsuitable for this task. Andrew Carnegie utilized the Bessemer Process in order to manufacture enough steel for the job. Within two decades from completing the bridge the United States displaced the U.K. as the world's largest steel producer.
This was the first large-scale application of steel as a structural material and initiated the shift from wrought-iron to steel as the default material for large structures.
By 1889, the U.S. output of steel exceeded that of the UK, and Carnegie owned a large part of it.
The Third Industrial Revolution - had to do with the information age. how computer technology converged with new energy ideas, mainly, renewable electricity dramatically increased productivity and digitize the economy.
The fourth Industrial Revolution which we're entering into now has to do with further networking computers and improvements to automation which will fall out of this. The internet of things and how everything is going to change when everything is connected, automated, and able to independently observe events, report to the collective, and react.
All of these revolutions the first and most famous, the second, and the lesser known and third and forth share the common observed effect of dramatically transforming the economy, jobs, and manufacturing. They all have to do with the all consuming task of continuously improving and refining manufacturing and the pursuit of new ideas and technologies which Adam smith first observed as having originated with the first.