I'm speaking of innovations for which all the ingredients were there but somehow it took a while to put them all together. Here are two examples:
- The phonograph. Edison's innovation was strictly mechanical. Machining techniques in the 1840s and 1850s were sufficiently advanced to permit building something very similar to Edison's device a good 25 years earlier. Imagine, if you will, an existing (remastered and digitized) recording of Lincoln delivering the Gettysburg Address...fascinating!
- The cable car. Andrew Hallidie Smith and William Epplseheimer built the first successful system in San Francisco in 1873 (although former Confederate general P. T. Beauregard demonstrated something along these lines in New Orleans in 1869 and received a patent). Anyhow, all the tools (wire cable with a rope core; cast iron; bronze bearings; etc.) were readily available. Perhaps New York, with an extremely high population density and long straight streets could have been the site of the first installation of cable traction some time in the 1850s, followed soon after by Baltimore, Boston, and Philadelphia.