The absolute population growth rate continued to speed up from the 1750s. From around 27% over the previous century, it reached 30% in the three decades from 1751 to 1781, 37% in the next three decades to 1811 and peaked at a 55% growth in the generation from 1811 to 1841. This was entirely the result of a high natural growth rate as fertility (the number of births) exceeded mortality. The Cornish were able to marry at a younger age than elsewhere because of the opportunities of earning some cash on and in the mines. Over the classical period of economic change that used to be called the industrial revolution before historians realised that it wasn’t actually a revolution, the population of Cornwall grew faster than that of England, Scotland and Wales, though somewhat slower than Ireland, where the spread of potato cultivation and sub-division of holdings helped to produce a population explosion that was not be sustained.
Nonetheless, as the absolute growth rate was steadily ratcheted upwards as the Cornish enthusiastically set out to prove they were one of the fastest breeding peoples of Europe, the difference wih England narrowed. In the century before 1750 our growth rate was twice that of England. In the next 30 years, it was still higher, but only by seven percentage points. In the period of the Napoleonic Wars it actually fell behind slightly. This may have been caused by the absence of men in the Navy as well as temporary economic difficulties experienced by the mining industry, disrupted by wartime conditions. Whatever the reason, in the immediate post-war generation the Cornish proved they could still out-breed the English, but only just.
Then, population growth abruptly slowed down. In the 1840s and 50s the population grew by just 4% in each decade, compared with growth rates of over 10% a decade in England. A temporary economic crisis in the late 1840s had triggered the beginnings of the ‘Great Emigration’ as Cornishmen and some women sought higher wages and better opportunities overseas. Even though the 1850s and early 1860s saw the peak production years of Cornish mining these were accompanied by continuing emigration, which dampened down the growth in numbers in the final decades of Cornwall’s industrial period.
Within Cornwall, the first 30 years of the 19th century saw a generalised population increase in all areas. Overall, numbers grew by 53% with population more than doubling in the Fowey, St Austell and Calstock districts, while still rising by 21% in the slowest growing districts of the Roseland and Meneage. The fastest growing areas were concentrated in mid-Cornwall, where copper mining had expanded after 1810, and in the older industrial heartland west of Truro.
During the period from 1831 to 1861 the microgeography pf Cornish population change displays the greatest diversity. While the overall growth fell back to 23%, some areas – notably Calstock (where numbers tripled), the booming new mining district around Liskeard, and Camborne saw growth rates of well over 60%. In contrast, population fell in many agricultural areas, and also in the rural mining parishes of Breage and Crowan.