506 



DRAINAGE 



nearly a foot of the depth of the ditch and are more 

 likely to become obstructed, especially if placed near 

 the surface, than are tile drains. The throats or open- 

 ings of stone drains are irregular in size, while those of 

 tile drains are smooth and uniform in size, and are, 

 therefore, most desirable. Years ago, various flat-bot- 

 tomed tiles (Fig. 73G) were used, but the only style in 

 general use at present is the cylindrical unglazed tile 

 shown in Fig. 737. 



In some sections drains are placed 200 to 300 feet apart, 

 and serve their purpose well. In others they should not 

 be placed farther apart than from 20 to 30 feet. Whert- - 

 ever the subsoil is composed of tenacious, fine clay, 

 through which the water moves upwards or downwards 

 with difficulty, the narrower in- 

 tervals are necessary. In some 

 instances the surplus water in 

 the subsoil is underpressure by 

 reason of water which finds its 

 way into it from higher levels, 

 and if this is not removed, the 

 water has a constant tendency 

 to rise to the surface. In many 

 such cases drains placed at wide 

 intervals may serve to relieve 

 the pressure and drain the land. 

 Since sub-drains are designed 

 to be permanent, are expensive 

 to construct and difiicult to re- 

 pair, the principles of drainage 

 should be well undtrstood, and 

 the work should be undertaken 

 only after a most can-ful inspec- 

 tion of the land and after the 

 fundamental principles of the 

 subject have been mastered. 



Mains and sub-mains should 

 be avoided so far as possible, 

 since they greatly increase cost, 

 tend to become obstructed, and 

 are often unnecessary. The 

 three long mains in Pig. 738 are 

 not drains, strictly speaking, 



may be more outlets to construct and maintain than is 

 desirable; if so, the system might be moditied by con- 

 structing a sub-main, one side of which will serve also 



737. Common cylindrical drain tile; and a scoop for 

 preparing the bed for the tile. 



since the land may be as fully drained without them, as 

 shown in Fig. 739 ; therefore, they only serve to conduct 

 the water of the drains proper. Tiles of 3 to 4 and 5 inches 

 diameter should be used when the drains are infrequent 

 and the flow of water considerable. Smaller ones, 2 to 3 

 inches in diameter, will suffice when the intervals be- 

 tween the drains are narrow. Drains should have as 

 uniform a fall as possible, and no abrupt lateral curves 

 or sharp angles should occur as are seen in many places 

 in Fig. 738. If the drain has a rapid fall in its upper 

 reaches, as is often the case, and but slight fall in the 

 lower, a silt basin should be constructed at the point 

 at which the rapid changes into the slight fall, if obstruct- 

 ing silt is present. All drains which may be necessary 

 should be placed before the planting occurs. Orchard 

 lands may be drained in the spring, fallowed in the sum- 

 mer, and planted in the fall or the following spring. 

 Drains placed at frequent intervals because of the te- 

 nacity of the soil should be comparatively shallow, for 

 if placed deep or at wide intervals, the water will be too 

 long reaching them. If drains are placed at wide inter- 

 vals they should be at least 3}4 feet deep to be most effi- 

 cient. Tf the parallel system is adopted {Fig. 739), there 



738. Improper method of drainine 



as a drain, and but one outlet will be required ( Fig. 740). 

 Drains through which water runs for the greater part 

 of the year are likely to become obstructed by roots, if 

 water-loving trees, such as the willow, soft maple and 

 elm, are allowed to grow near them. If floating silt is 

 present the joints of the tiles should be protected for 

 two-thirds of their upper circumferences by a narrow 

 strip of tarred building paper, or collars should be used. 

 Stone drains should receive a liberal covering of straw 

 before they are filled. j. p. Roberts. 



DREER, HENRY A. Seedsman, and founder of one 

 of the oldest American horticultural establishments; 

 was born in Philadelphia, Aug. 24, 1818, and died thei'e 

 Dec. 22, 1873, at the age of fifty-five. His parents were 

 Frederick Dreer, of Hanover, and Fredericka Augusta 

 Nolthenius, of Grossakenheim, Gennany. They were 

 married in America. The Nolthenius family emigrated 

 to the United States in the last decade of the eigh- 

 teenth century, and were closely connected with the 

 Lutheran Church. Henry A. Dreer's education was 

 largely in German, and obtamed in Philadelphia. He was 

 fond of -:;it!icriii^' sit-ds and ]>lants in the country, and 

 wouhl \>nu'^ lliriii huiiu- to cultiv-ute. He was trained in 

 his fatlin -s l>uMii.-v, that ..f a rabinet-maker. In 1838, at 

 the stjluitutiuu v{ a frit-nd. he began as a florist in a 

 small way, near Front and Chester Sts. About 1870 he 

 removed to Seventh and Chestnut. In 1869 he enjoyed 

 a 5 months' trip to Europe, where he met business cor- 

 respondents of 30 years' standing. He was married 

 June 22, 1847. to Mary Leavenworth, of Reading, Pa., 



739. Best method of drai 



