of the drains, the terms "frequent" and "parallel" were also
applied to it. Smith himself more appropriately named it, from its
effects, "thorough draining." The sound principles thus promulgated by
him were speedily adopted and extensively carried into practice. The
great labour and cost incurred in procuring stones in adequate
quantities, and the difficulty of carting them in wet seasons, soon led
to the substitution of "tiles," and soles of burnt earthenware. The
limited supply and high price of these tiles for a time impeded the
progress of the new system of draining; but the invention of tile-making
machines removed this impediment, and gave a stimulus to this
fundamental agricultural improvement. The substitution of cylindrical
pipes for the original horse-shoe tiles has still further lowered the
cost and increased the efficiency and permanency of drainage works.

The system introduced by Smith of Deanston has now been virtually
adopted by all drainers. Variations in matters of detail (having respect
chiefly to the depth and distance apart of the parallel drains) have
indeed been introduced; but the distinctive features of his system are
recognized and acted upon.

A great stimulus was given to the improvement of land by the passing
in England of a series of acts of parliament, which removed certain
obstacles that effectually hindered tenants with limited interests
from investing capital in works of drainage and kindred amelioration.
The Public Money Drainage Acts 1846-1856 authorized the advance of
public money to landowners to enable them to make improvements in
their lands, not only by draining, but by irrigation, the making of
permanent roads, clearing, erecting buildings, planting for shelter,
&c. The rapid absorption of the funds provided by these acts led to
further legislative measures by which private capital was rendered
available for the improvement of land. A series of special improvement
acts were passed, authorizing companies to execute or advance money
for executing improvements in land. Finally, the Land Improvement Act
1864, amended and extended by the act of 1899, gave facilities for
borrowing money by charging the cost of draining, &c., as a
rent-charge upon the inheritance of the land. The instalments must be
repaid with interest in equal amounts extending over a fixed term of
years by the tenant for life during his lifetime, the tenant being
bound to mai