DRAINAGE. 135 



But it must be borne in mind that the steeper the grade the greater the danger of sur 

 face wash, which often causes great loss of manure, and even of soil itself. 



As to the proper size of tiles to use, it is difficult to give a rule that will apply to all cases, 

 so many considerations having to be taken into account ; but, as we have previously stated, 

 it is safer to have the mains and laterals larger than necessary, rather than too small. For 

 this reason we should feel more inclined to follow Mr. Chamberlain s rule than the one pre 

 viously given, and commonly applied, but which will not meet the requirements of all cases. 

 A two-inch pipe tile is largely used for laterals. By using such small tiles they can be placed 

 nearer together than more remote larger ones, at no greater expense, hence better drainage 

 can be secured at the same expense, by their use. 



Among the various kinds of tile manufactured and in use, the round tile seems to be 

 most in favor. In many sections tiles round inside and octagonal externally are quite popu 

 lar, while others still prefer the sole tile and other varieties. Cylindrical pipes with collars 

 are considered the best by English authorities ; the collars being simply short pieces of pipe 

 just wide enough in diameter to admit freely the smaller pipes that form the drain ; hence, 

 in use, one of these collars is so placed as to receive and hold the end of each tube where 

 they join, keeping them in position to form a continuous canal for the free passage of water, 

 and guarding against the entrance of mud, sand, vermin, or other obstructions. These joints, 

 which are frequent, also admit the water furnished by the soil. It may seem almost impossible 

 that lands could be drained by the water entering only at these joints in the tiles thus laid, but 

 it is proven to be a fact ; water will find its way to such places in the drains and make them 

 the permanent places for reaching eventually the mains, and it is surprising to see how soon 

 after a rain commences these mains will begin to discharge their contents received from the 

 laterals, and often to their fullest capacity. 



Hard-burnt tiles should be selected for the purpose ; those having any defect whatever 

 should be discarded. They should be carefully examined before being laid, and whenever 

 there is found one with a lump of unslacked lime, or lime pebbles, or any small hole, it should 

 not be used. To determine whether there is unslacked lime in the tile, immerse it in water 

 and allow it to remain until thoroughly soaked through ; if it contains lime it will break. The 

 breakage of such a tile when placed and covered by the soil might make an obstruction that 

 would cause days of labor and expense to find and repair. Waring advises that each tile be 

 examined by a stroke from a hammer, and every one be rejected that does not give a clear 

 metallic ring.. Mr. Chamberlain, previously referred to, recommends the glazed tiles as most 

 desirable, and describes them as follows : 



&quot; They are made of fire clay or second quality potter s clay, like that used for sewer pipes, 

 burnt hard and glazed. They are about as dark colored and smooth as a little brown jug, 

 and seem likely to be as durable. They are the only kind I shall use hereafter. 



I think tiles made of ordinary brick clay are liable to soften and crumble and decay, cer 

 tainly if exposed to frost. After the first job of draining I did, I had a few of these red 

 brick tiles left. They lay on the ground through one of our changeable winters, and the com 

 bined action of moisture and frost crumbled most of them to pieces. And unless burnt very 

 hard indeed, I should fear the same result in time, even when laid below frost, for we have 

 noticed that in a mass of brick, even buried in the ground, all the soft ones will crumble in 

 time, even without the action of frost. But with the hard, glazed tiles I now use, with their 

 clear metallic ring, and their glazed surface inside and out, impervious to water, crumbling 

 and dissolution seem impossible. I have tested them very thoroughly in moisture and frost 

 two winters, in small heaps above ground ; and I do not see but that they are likely to last as 

 long as a broken bit of a glazed jug, or some of the broken tiles or bricks of ancient cities, 

 unearthed after centuries of oblivion. 



Now this seems to me an important matter. Drainage, if properly executed, is a perma- 



