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Ductile iron could have been invented before 1808 if Davy had produced magnesium sooner. So this is a 'turtles all the way down' explanation. Or is it? Imagine

Ductile iron could have been invented before 1808 if Davy had produced magnesium sooner. So this is a 'turtles all the way down' explanation. Or is it? Imagine a directed graph of technologies where each node has outgoing links to its dependencies. Nodes may be added randomly (if their dependencies are present), but we don't consider them important until important things depend on them. In other words, there is a PageRank threshold for "inventions". Instead of adding possible new nodes uniformly at random, we might assume their chance of discovery is inversely proportional to the sum of the PageRanks of their dependencies. Similarly, a new web page is unlikely to link to many obscure pages. (Alternatively, I think you can add nodes randomly and periodically delete low-ranking nodes.)

davidivadavid 7y ago
I've been digging into the topic since "progress studies" got more popular, but it seems like no one has done much in that direction (which is also what my initial hunches suggested should be tried). There's a lot of grunt work to do if you want to label the data to match our current technological reality, but in the abstract, it still seems to me that building such models could yield interesting insights. You can add all sorts of bells and whistles to make it more interesting (play with diffusion speed, the inherent difficulty of the discoveries required, etc.).
pfdietz 7y ago
The Davy reference was a bit aggressive, I must confess. The early ways of making magnesium metal would have worked on a lab scale, and would have been frightfully expensive. Practical Mg production had to wait for the large scale production of electric power for electrolysis, or for the production of silicon (in electric arc furnaces) for the Pidgeon process. Still, magnesium was being produced in large quantities by WW 1, if not before.
- philipkglass 7y ago
  "The History of Magnesium" https://sci-hub.tw/10.1111/j.1559-3584.1957.tb04052.x https://sci-hub.tw/10.1111/j.1559-3584.1957.tb04052.x Industrial-scale production began in Germany in 1886. There was another significant change in 1924-1925 with the development of a truly anhydrous chloride melt, which significantly reduced anode wear and increased energy efficiency. For the production of ductile iron, one major challenge was managing the loss of magnesium by boiling since the BP of Mg is so much lower than the MP of cast iron. "Fundamentals of Magnesium Addition to Ductile Iron" https://sci-hub.tw/10.4271/640802 https://sci-hub.tw/10.4271/640802 You can see multiple gating factors for why magnesium based production of ductile iron was not discovered (or at least industrialized) earlier: - Early industrial magnesium production was expensive due to high electrolytic anode wear from impure raw materials. - Electrolytic magnesium production was also expensive due to the high cost of electric power; 1880s-era generators had low thermal efficiency and generated electricity at high costs [1]. - Early ductile iron production suffered from high losses of costly magnesium, due to boil-off. The various economizing measures described in the second paper I linked above did not yet have their own enabling technologies available in the 19th century. [1] I'm not going to try to reproduce my full work here, but I was surprised at the high cost of electricity I found referenced in an American chemical engineering textbook from 1940. On further investigation of the consumer price index and published historical electricity prices, I found that electricity was (by contemporary American standards) quite expensive before WW II, and relatively expensive through the 1950s. It wasn't until the 1960s that electricity became fairly cheap.
  - pfdietz 7y ago
    Good points, thanks.

davidivadavid 7y ago

I've been digging into the topic since "progress studies" got more popular, but it seems like no one has done much in that direction (which is also what my initial hunches suggested should be tried). There's a lot of grunt work to do if you want to label the data to match our current technological reality, but in the abstract, it still seems to me that building such models could yield interesting insights. You can add all sorts of bells and whistles to make it more interesting (play with diffusion speed, the inherent difficulty of the discoveries required, etc.).

pfdietz 7y ago

The Davy reference was a bit aggressive, I must confess. The early ways of making magnesium metal would have worked on a lab scale, and would have been frightfully expensive. Practical Mg production had to wait for the large scale production of electric power for electrolysis, or for the production of silicon (in electric arc furnaces) for the Pidgeon process. Still, magnesium was being produced in large quantities by WW 1, if not before.

philipkglass 7y ago
"The History of Magnesium" https://sci-hub.tw/10.1111/j.1559-3584.1957.tb04052.x https://sci-hub.tw/10.1111/j.1559-3584.1957.tb04052.x Industrial-scale production began in Germany in 1886. There was another significant change in 1924-1925 with the development of a truly anhydrous chloride melt, which significantly reduced anode wear and increased energy efficiency. For the production of ductile iron, one major challenge was managing the loss of magnesium by boiling since the BP of Mg is so much lower than the MP of cast iron. "Fundamentals of Magnesium Addition to Ductile Iron" https://sci-hub.tw/10.4271/640802 https://sci-hub.tw/10.4271/640802 You can see multiple gating factors for why magnesium based production of ductile iron was not discovered (or at least industrialized) earlier: - Early industrial magnesium production was expensive due to high electrolytic anode wear from impure raw materials. - Electrolytic magnesium production was also expensive due to the high cost of electric power; 1880s-era generators had low thermal efficiency and generated electricity at high costs [1]. - Early ductile iron production suffered from high losses of costly magnesium, due to boil-off. The various economizing measures described in the second paper I linked above did not yet have their own enabling technologies available in the 19th century. [1] I'm not going to try to reproduce my full work here, but I was surprised at the high cost of electricity I found referenced in an American chemical engineering textbook from 1940. On further investigation of the consumer price index and published historical electricity prices, I found that electricity was (by contemporary American standards) quite expensive before WW II, and relatively expensive through the 1950s. It wasn't until the 1960s that electricity became fairly cheap.
- pfdietz 7y ago
  Good points, thanks.