But historical testimony exists which removes all obscurity from the inquiry as to who were the instructors of the Singhalese. The most ancient books of the Hindus show that the practice of canal-making was understood in India at as early a period as in Egypt. Canals are mentioned in the Rayamana, the story of which belongs to the dimmest antiquity; and when Baratha, the half-brother of Rama, was about to search for him in the Dekkan, his train is described as including "labourers, with carts, bridge-builders, carpenters, and diggers of canals." (Ramayana, CARY'S Trans., vol. iii. p. 228.) The Mahawanso, removes all doubt as to the person by whom the Singhalese were instructed in forming works for irrigation, by naming the Brahman engineer contemporary with the construction of the earliest tanks in the fourth century before the Christian era. (Mahawanso, ch. x.) Somewhat later, B.C. 262, the inscription on the rock at Mihintala ascribes to the Malabars the system of managing the water for the rice lands, and directs that "according to the supply of water in the lake, the same shall be distributed to the lands of the wihara in the manner formerly regulated by the Tamils." (Notes to TURNOUR'S Epitome, p. 90.) To be convinced of the Tamil origin of the tank system which subsists to the present day in Ceylon, it is only necessary to see the tanks of the Southern Dekkan. The innumerable excavated reservoirs or colams of Ceylon will be found to correspond with the culams of Mysore; and the vast erays formed by drawing a bund to intercept the water flowing between two elevated ridges, exhibit the model which has been followed at Pathavie, Kandelai, Menery, and all the huge constructions of Ceylon, But whoever may have been the original instructors of the Singhalese in the formation of tanks, there seems every reason to believe that from their own subsequent experience, and the prodigious extent to which they occupied themselves in the formation of works of this kind, they attained a facility unsurpassed by the people of any other country. It is a curious circumstance in connection with this inquiry, that in the eighth century after Christ, the King of Kashmir despatched messengers to Ceylon to bring back workmen, whom he employed in constructing an artificial lake. (Raja-Tarangini, Book iv. sl. 505.) If it were necessary to search beyond India for the origin of cultivation in Ceylon, the Singhalese, instead of borrowing a system from Egypt, might more naturally have imitated the ingenious devices of their own co-religionists in China, where the system of irrigation as pursued in the military colonies of that country has been a theme of admiration in every age of their history. (See Journal Asiatique, 1850, vol. lvi. pp. 341, 346.) And as these colonies were planted not only in the centre of the empire but on its north-west extremities towards Kaschgar and the north-east of India, where the new settlers occupied themselves in draining marshes and leading streams to water their arable lands, the probabilities are that their system may have been known and copied by the people of Hindustan.
The first tank in Ceylon was formed by the successor of Wijayo, B.C. 504, and their subsequent extension to an almost incredible number is ascribable to the influence of the Buddhist religion, which, abhorring the destruction of animal life, taught its multitudinous votaries to subsist exclusively upon vegetable food. Hence the planting of gardens, the diffusion of fruit-trees and leguminous vegetables[1], the sowing of dry grain[2], the formation of reservoirs and canals, and the reclamation of land "in situations favourable for irrigation."
1: Beans, designated by the term of Masá in the Mahawanso, were grown in the second century before Christ, ch, xxiii. p, 140,
2: The "cultivation of a crop of hill rice" is mentioned in the Mahawanso B.C. 77, ch. xxxiv. p. 208.
It is impossible to over-estimate the importance of this system of water cultivation, in a country like the north of Ceylon, subject to periodical droughts. From physical and geological causes, the mode of cultivation in that section of the island differs essentially from that practised in the southern division; and whilst in the latter the frequency of the rains and abundance of rivers afford a copious supply of water, the rest of the country is mainly dependent upon artificial irrigation, and on the quantity of rain collected in tanks; or of water diverted from streams and directed into reservoirs.
As has been elsewhere[1] explained, the mountain ranges which tower along the south-western coast, and extend far towards the eastern, serve in both monsoons to intercept the trade winds and condense the vapours with which they are charged, thus ensuring to those regions a plentiful supply of rain. Hence the harvests in those portions of the island are regulated by the two monsoons, the yalla in May and the maha in November; and seed-time is adjusted so as to take advantage of the copious showers which fall at those periods.
1: See [Vol. I. Part I. ch. ii p. 67.]
But in the northern portions of Ceylon, owing to the absence of mountains, this natural resource cannot be relied on. The winds in both monsoons traverse the island without parting with a sufficiency of moisture; droughts are of frequent occurrence and of long continuance; and vegetation in the low and scarcely undulated plains is mainly dependent on dews and whatever damp is distributed by the steady sea-breeze. In some places the sandy soil rests upon beds of madrepore and coral rock, through which the scanty rain percolates too quickly to refresh the soil; and the husbandman is entirely dependent upon wells and village tanks for the means of irrigation.
In a region exposed to such vicissitudes the risk would have been imminent and incessant, had the population been obliged to rely on supplies of dry grain alone, the growth of which must necessarily have been precarious, owing to the possible failure or deficiency of the rains. Hence frequent famines would have been inevitable in those seasons of prolonged dryness and scorching heat, when "the sky becomes as brass and the earth as iron."