, p. 23.

[21] _Ibid._, p. 24.

[22] _Outlines of the Economic History of England_ (London, 1908), p. 118.

[23] _Growth of Eng. Ind. and Commerce_ (Cambridge, 1892), p. 180.

[24] _England's Industrial Development_ (London, 1912), p. 247.

[25] _English Economic History_ (New York, 1893), part ii, p. 262.

[26] Carew, _Survey of Cornwall_ (London, 1814), p. 77.

[27] Cunningham, _Growth of English Industry and Commerce, Modern
Times_, 1903, part i, p. 101.

[28] Lennard, _Rural Northamptonshire_ (Oxford, 1916), p. 87. For
other examples, _cf. infra_, pp. 84, 99-101.

[29] Leonard, _Royal Hist. Soc. Trans._, 1905. Gonner in _Common Land
and Inclosure_ covers much the same ground, but does not bring out as
clearly the extent to which the seventeenth century enclosures were
accompanied by conversion of tilled land to pasture.

[30] Tawney, _Agrarian Problem in the Sixteenth Cen._ (London, 1912), p.
391.

[31] _Royal Hist. Soc. Trans._ (1905), vol xix, note 1, p. 113.

[32] _Ibid._, pp. 116-117.

[33] Rogers, _History of Agriculture and Prices_, vol. iv, p. 757.

[34] _Cf. infra_, p. 98.

[35] Levett and Ballard, _The Black Death_, p. 129.

[36] _Cf. infra_, p. 82.

[37] Tawney, _op. cit._, p. 220, note 1.

[38] _Infra_, p. 78, 81, 98-9.

CHAPTER II

THE FERTILITY OF THE COMMON FIELDS

Up to this point attention has been given chiefly to the theory that
the enclosure movement waxed and waned in response to supposed
fluctuations in the relative prices of wool and grain, and it has been
found that this theory is untenable. It is now necessary to consider
more closely the true cause of the conversion of arable land to
pasture--the declining productivity of the soil--and the cause of the
restoration of this land to cultivation--the restoration of its
fertility.

The connection between soil fertility and the system of husbandry has
been explained by Dr. Russell, of the Rothamsted Experiment Station:

Virgin land covered with its native vegetation appears to alter
very little and very slowly in composition. Plants spring up,
assimilate the soil nitrates, phosphates, potassium salts, etc.,
and make considerable quantities of nitrogenous and other organic
compounds: then they die and all this material is added to the
soil. Nitrogen-fixing bacteria also add to the stores of nitrogen
compounds. But, on the other hand, there are losses: some of the
added su