... in productive equipment.

However, by their nature, they show up most clear in production in the productive equipment that is relied on most heavily in that wave of innovations. So, for the great surge in steam power, the number of fixed steam engines and locomotives tells the tale of the boom and tailing off ... but it doesn't say anything about the establishment of the crude oil productive system.

In historical research, this is fine ... we can identify what the equipment that had the strongest complementarity with the balance of the innovation wave, and trace out the surge in investment in that equipment.

For an indicator, of course, that would be like looking for a recession in the aggregate GDP data ... we are reasonably confident about the GDP data for Quarter 1 by the end of Quarter 2, and so can be confident that we were in a recession on the definition of two consecutive quarters of reduction in GDP, by the end of Quarter 3. And by the end of Quarter 3, most of the GDP recessions that we have experienced since the end of WWII would be over, with the economy starting to grow again.

Mind you, any wave of investment in productive equipment associated with a new technology is part of a wave of innovation ... that's what innovation is, putting a new technology to use. However, whether its the next wave along the existing technological channel, or breaking ground for a new technological channel ... that's far easier to see in retrospect.

There is much of this in the literature on Kondratieff  cycles, but much of that is focused on the question of whether these cycles have a regular periodicity ... his theory was that capitalist economies have a long cycle of about 50-60 years.

In this context, there are two steps between the general observation of the cyclic character of economic innovations and Kondratieff theory as such ... the first is whether Kondratieff was correct, and the second is whether the cycle would remain substantially the same given the massive institutional change that we must proceed with in order to achieve an ecological sustainable economic system.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

I am not sure you could see waves in a quantitative indicator every time. But I think we have seen waves of new business whenever technology reached an enabling threshold, so besides the "liquid fuels" revolution:

• progress in shipbuilding and navigation enabled the discovery of the New World, it was a business venture. Later other improvement in ship design like clippers made it economically viable to move actual goods to/from colonies and not just loot the gold
  
• physiocratic theories applied to agriculture boosted output during the 19th century, freeing workforce for manufacturing
  
• the industrial steel furnace is a revolution in itself in my view, just a big a jump as from bronze to iron: cheaper and harder tools and fixtures, enabling manufacturers to churn out yet more new fixtures ever cheaper with new mechanized manufacturing processes based on steel tooling and heavy machinery. This one was a virtuous cycle culminating now with the digital control micrometric machine tool, the automatized assembly chains, and may be someday the Asimov robot (may be pretty soon, a humanoid robot doesn't need to be much smarter than a dog to have a huge impact on the labor market). Of course, it also kept shedding jobs at the same time, but it is the way we have refrigerators to keep our food fresh, cars, vacuum cleaners, etc...
  
• progress in medicine has increased the strength of the workforce, and its number by better life expectancy, with milestones at vaccination and antibiotics, and the perfection of the cesarean surgery
  
• progress in weapons has delivered the nuclear-tipped ICBM and the balance of terror, freeing the industrialized countries of the infrastructure destructions-rebuilding incurred by conventional wars every other decade
  
• progress in specialty maths and semiconductors made the computing revolution, eliminating many bookkeeping tasks, enabling new business models that are in essence only smart bookkeeping in many industries, and created new boring consultancy jobs
  
• progress in space, fiber technologies and semiconductors (again) enabled the communication revolution, global corporations with economies of scale, internet and main-stream media, and wage arbitrage.

The important thing to note in my view, is that it is an exponential process. We're past the point when progress in a single area of science had life-changing impacts (save possibly biotech, but the experimentation latency in this field will make the impacts slower than other revolutions). It is now more the outcome of exploration of the possibilities offered by combinations of technologies, and the combinatorics push the border faster and faster.

In my view, since the 60's (the decade of the mosfet, the communication satellites, the DNA ...) we have seen innovation change lives like never before. It's not relenting, but people no longer pay attention and live surrounded by "magic", they shrug at the marvels. Obviously, despite the improvement in technology, there won't be much to show off in this century (car can't get supersonic, TV can't get bigger than houses...) Only biotech could have an impact (making immortals some day), or sooner we could have omnipresent robots. Forget thought control, it won't make a change, we already have it full time. It's called TV + pervasive computing.

Pierre