1662 Report of Farmers' Institutes 



different methods of constructing covered drains 



Poles, briisli aud stone have been used in constructing covered 

 drains and have done good service in aiiording drainage. Their 

 use was much more permissible in former years than at present 

 when a good quality of drain tile can be had in most sections of 

 the country. All those materials have the disadvantage of short 

 life and often high cost for construction. If stones are used they 

 had best be arranged without any definite throat. The ditch 

 should be relatively large. The stones should be dumped in pro- 

 miscuously except that the small, flat stone should be on the top 

 and bottom. The water finds its way through the large spaces 

 and the small stone on top reduce the danger of clogging. Flat 

 stone may be arranged face to face with the flat sides parallel to 

 the walls of the ditch. The top should be covered with small, flat 

 stone. 



TILE DRAINS ; THE BEST QUALITY OF TILE 



The preeminent material for modern land drainage is tile. 

 They come in different shapes and of different quality. By a 

 process of evolution we have come to prefer round or hexagonal 

 shaped tile because they are easiest to lay and least likely to clog. 

 They may be made of burned clay or of concrete. Clay tile may 

 be either vitrified or unvitrified. The former is most durable be- 

 cause its walls are least porous. The difference lies in the quality 

 of clay used and the degree of heat applied in Inirniiig. Vitrifica- 

 tion means partial melting of the clay particles which run together 

 in a very dense mass. A low degree of porosity coincident with a 

 moderate degree of vitrification is especially desired where the tile 

 is likely to freeze. In the soil the pores in the tile become filled 

 with water and if it freezes in this condition the Avails of the tile 

 may be fractured and broken up into scales. If only one or two 

 tile in a long line are thus destroyed the service of the drain is 

 jeopardized. Since vitrified tile cost no more on the average than 

 soft tile, there is no excuse for taking the risk in using the soft 

 tile. 



The drainage efficiency of the tile is not affected by the differ- 

 ence in the porosity of the walls since the water enters at the joints. 



'Cement tile that are of fairly good quality may be made by hand 

 or in machines. It is doubtful if thev can be made as durable as 



