When did the Industrial Revolution start?

Had I mentioned that the Journal of Political Economy is my favorite academic journal?  In the December 2005 issue, the still under-valued Gregory Clark writes:

I use building workers’ wages for 1209-2004 and the skill premium to consider the causes and consequences of the Industrial Revolution.  Real wages were trendless before 1800, as would be predicted for the Malthusian era.  Comparing wages with population, however, suggests that the break from the technological stagnation of the Malthusian era came around 1640, long before the classic Industrial Revolution, and even before the arrival of modern democracy in 1689 [TC: was that when it came?].  Building wages also conflict with human capital intepretations of the Industrial Revolution, as modeled by Gary Becker, Kevin Murphy…and Robert Lucas.  Human capital accumulation began when the rewards for skills were unchanged and when fertility was increasing.

Here is an earlier but longer version of the paper.  Here is an on-line version of his book on growth.  Here is a previous MR post on the long, slow nature of the Industrial Revolution.