Mi has helped me to calculate the annual population total for three counties: Cumberland (where the Dalemain estate lies), Norfolk (Holkham Hall) and Sussex (Petworth). There is a graph below. Since the area of the county, didn't change, we can use the population figures as representing population densities. I tried including population density in the panel data regression, but it wasn't significant. I think we'll try the population size of the nearest market town to the estate. That worked well for the 'Devon' data. Take a look at the graph: can you see that the population of Sussex more than doubled in half a century? This huge growth meant many more mouths to feed and so required agriculture to increase its yields. The area of cultivatable land is fixed and so the only way to increase output is to increase the yields. This is a close parallel to the world situation today: food prices are climbing because the global population is swelling. That's one reason why the work we are doing has relevance.
I'll spend today at UBC getting more maps of railway construction: the Victorians helped solve their food problem by transporting agricultural output more efficiently. Lessons to be learned!