At the end of the seventeenth century, about half the land of England and Wales was, according to the best authorities, held to be under cultivation, either as arable or pasture. As the whole area of England and Wales is about thirty-seven millions of acres, this would show a cultivation of eighteen million five hundred thousand acres. The entire quantity of wheat, rye, barley, oats, pease, beans, and vetches, grown upon these eighteen million and a half acres, was estimated at less than ten millions of quarters, wheat being little more than a sixth of the whole produce. The quantity of stock annually fattened for food was even more inconsiderable. We may safely assume that in a century and a half the amount of agricultural produce in England has increased five-fold. Two-thirds of the whole area of England and Wales are now under cultivation; for in the census returns of 1851 we have twenty-five million acres of farm holdings, occupied by two hundred and twenty-five thousand farmers. In the calculations of Gregory King, in 1688, the number of farmers was given at a hundred and fifty thousand; but the number of lesser freeholders, who were doubtless cultivators, was also a hundred and twenty thousand. The produce of the land has increased at a greater rate than the increase of population. According to the commonly received estimates, the population of England and Wales was about five millions and a half, perhaps six millions, at the end of the seventeenth century; it is now eighteen millions. The inhabited houses, according to the hearth-books of 1690,[40] were one million three hundred and twenty thousand. In 1851 they were three million two hundred and seventy-eight thousand. The hearth-books of 1685 show that, of the houses of the kingdom, five hundred and fifty-four thousand had only one chimney--they were mere hovels.