The wonderful remains of ancient cities, tanks and water-courses throughout the island all prove that the now desolate regions were tenanted by a multitude--not of savages, but of a race long since passed away, full of industry and intelligence.
Among the existing traces of former population few are more interesting than those in the vicinity of Newera Ellia.
Judging from the present supply of water required for the cultivation of a district containing a certain population, we can arrive at a tolerably correct idea of the former population by comparing the present supply of water with that formerly required.
Although the district of Ouva is at present well populated, and every hollow is taken advantage of for the cultivation of paddy, still the demand for water in proportion to the supply is comparatively small.
The system of irrigation has necessarily involved immense labor.

For many miles the water is conducted from the mountains through dense forests, across ravines, round the steep sides of opposing hills, now leaping into a lower valley into a reservoir, from which it is again led through this arduous country until it at length reaches the land which it is destined to render fertile.
There has been a degree of engineering skill displayed in forming aqueducts through such formidable obstacles; the hills are lined out in every direction with these proofs of industry, and their winding course can be traced round the grassy sides of the steep mountains, while the paddy-fields are seen miles away in the valleys of Ouva stretched far beneath.
At least eight out of ten of these watercourses are dry, and the masonry required in the sudden angles of ravines, has, in most cases, fallen to decay.

Even those water-courses still in existence are of the second class; small streams have been conducted from their original course, and these serve for the supply of the present population.
From the remains of deserted water-courses of the first class, it is evident that more than fifty times the volume of water was then required that is in use at present, and in the same ratio must have been the amount of population.

In those days rivers were diverted from their natural channels; opposing hills were cut through, and the waters thus were led into another valley to join a stream flowing in, its natural bed, whose course, eventually obstructed by a dam, poured its accumulated waters into canals which branched to various localities.
Not a river in those times flowed in vain.

The hill-sides were terraced out in beautiful cultivation, which are now waving with wild vegetation and rank lemon grass.