MISCELLANEOUS PAPERS. 409 



Dentou's system, though excellent when carried out with the broken stone 

 covering that he recommended, has few features to recommend it for use on a 

 road where in all probability no covering beside the native soil will be applied. 

 The total cost per rod of such tile drain is reckoned by him at less than one 

 English shilling, where the tile costs 20 shilling (English) per 1,000 feet and 

 labor of excavating costs 3 pence per yard, and laying and treadmg in 6| pence 

 per chain of four rods. 



The second system, in which a drain is placed directly beneath each side 

 ditch, formed in turnpiking, has the advantage of relieving the side ditches of 

 much of their work, thus keeping them more free from water, and the disad- 

 yantage of being so far from the center of the road as to affect but little the 

 water that may ])e beneath the travelled way. 



The third system, in which one drain is placed directly beneath the traveled 

 way, has the advantages of being cheaper than the others, inasmuch as less 

 tile and labor would be required, and of conveying away rapidly the water 

 du'ectly beneath the traveled track, and the disadvantage, if it be one, of 

 affecting but slightly the water that may be in the side channels. Two drains 

 of two-inch tile are recommended in both the other systems, and one of three- 

 inch in this. 



The third system, where a single under-drain is placed beneath the axis of a 

 well turnpiked road, will provide efficient drainage for all cases that will ordi- 

 narily arise, and is the only method that will be considered farther in this 

 article, though, in many cases, the others may be preferable. We may add, 

 however, that with a road surface of gravel or broken stone, a very large pro- 

 portion of the water would be conveyed at once to the oj^eu side ditches, and 

 the second system of under-drains w^ould, in such a case, be preferable to the 

 third ; but with our ordinary roads I am inclined to believe a single drain 

 beneath the center of the road preferable to two, one under each open side 

 ditch. 



It is not within the province of this article to treat fully of the various meth- 

 ods of underdrainage. The points requiring most attention are the only ones 

 here mentioned. The drain should be not less than three feet deep, and when- 

 ever practicable four feet deep. An outlet should be provided in every depres- 

 sion of the road, which outlet must consist of a transverse nnderdrain or a 

 culvert emptying in a stream, water-course, or reservoir, where the presence of 

 Avater will not affect the road. 



The drain should run from this outlet Avith a continuous ascent in both Avays 

 to the top of the nearest elevations that lie in the line of the road. Here the 

 ends may be stopped and a break of a few feet left in the drain, or it may be 

 continued on uninterrupted to the next depression, Avhere another outlet must 

 be formed, as described. 



The tiles should be laid Avith the closest possible joint, and the joint should 

 be farther protected by a collar made on purpose, or by a closely moAved piece 

 of tough turf a few inches square, laid Avith the grass side towards the tile so as 

 to enclose the joint. The tile should be round in the cross section, so that it may 

 be laid any side up. On no account use lioj'se-shoe tile, Avhether with or Avithout a 

 bottom. Where tile cannot be obtained, stone or brush may be used ; but the 

 drain formed by them Avill be inferior to that formed by tile. A stone drain 

 may be formed by making a cliannel with flat stone, or by putting in small 

 cobble stone promiscuously, to the depth of eight or twelve inches, and coA'er- 

 iug Avith straAv and earth. Brush drains are made by laying the brush length- 



52 



