62 ON THE BIFKOYEMENT OF WASTE LAND OX THE 



The fall in this plain from end to end is only 10 feet, so that 

 in former days the water, after souring the ground, went off 

 chiefly in evaporation. It is therefore not surprising that the air, 

 which used even in summer to be cold and damp for a great 

 distance round, is now warm and genial ; the ground, which was 

 as I have described it, being now perfectly dry. 



The cost of a portion was L.6, 16s., and a portion L.6, 4s., so 

 that the average was about L.6, 10s. per acre. 



This outlay is large, but there were several causes of expense 

 which do not commonly occur ; for instance, a new course had 

 to be cut for one of the mountain streams, and the main or centre 

 stream widened from 7 to 14 feet. The large and deep leading 

 drain, which takes all the drainage water on both sides of this 

 stream, was of course expensive. There are two sub-leaders 

 passing under the stream, one falling in about 1000 yards up 

 the main drain, the other 100 yards from the outfall. The former 

 is 2 1 feet under the bed of the stream, and is composed of fire- 

 clay glazed pipes, over which the gravel is merely filled in, the 

 joints being perfectly tight ; for where there is no shifting, gravel 

 is as tight in a short time, if always submerged, as any puddling. 

 The latter is one foot under the bed of the stream, and is carried 

 across by 9-inch fire-clay glazed pipes, so that these are about 

 level with the bed of the stream when placed. In laying them, 

 the stream above the crossing was temporarily turned into the 

 great drain, and the pipes were made perfectly water-tight by 

 beinsc enclosed in a casing of Portland cement concrete 5 inches 

 thick. Wlien this was hard, the stream was returned to its 

 course, and now flows over the cement, which is harder than most 

 kinds of stone. This sub-leader, before crossing the stream, 

 passes through 30 yards of rock from 1 to 2 feet deep, the only 

 rock met with during the progress of the work except on first 

 breaking o-round. 



In the course of the work, some very heavy springs were 

 found ; one in particular, in the deep moss, throwing after heavy 

 rains a body of water (enough to fill a 2-incli pipe) about a foot 

 high above the surface, as if on force. When a drain was taken 

 througli this spring, it was found to have made a large and very 

 deep hole imder the 4-feet cut, and before it could be laid with 

 pipes, a number of cart-loads of gravel and small stones were put 

 in until a run for the water was got suiting the rest of the drain, 

 which was laid with 3-inch pipes. Over these, for about 4 yards 

 on each side of the spring, 6-inch pipes were put about half an 

 inch apart, forming a drain witliin a drain. These pipes were 

 then covered with field stones to within a foot of the surface, and 

 turfed over to prevent earth getting down, and all heavy springs 

 were dealt with in this way. This expedient has never been 

 found to fail, either in the case of springs or old stone drains so 



