RURAL ENGINEERING. 685 



7-ft. depth, and i : 1 slide slopes, while the handmade ditches usually have 

 i5-ft. bottom widths, 5-ft. depths, and i : 1 side slopes. A berm of 8 ft. is 

 recommended for the dredged channels, and of 3 ft. for the handmade ditches. 

 The width of right of way varies as follows : For 3-ft. ditch, 30 ft. ; for 14-ft. 

 ditch, 80 ft. ; for 16 to 20-ft. ditch, 90 ft. ; for 22-ft. ditch, 100 ft. ; and for 28 to 

 30-ft. ditch, 120 ft. 



The proposed improvement in Boggy Swamp consists of a ditch throughout 

 the length of the swamp, 13,000 ft. of which is handmade, with 3-ft. bottom 

 width, 6-ft. depth, and side slopes i : 1; and 62,800 ft. of dredged ditch in- 

 creasing from minimum size to a bottom width of 30 ft. at the lower end. The 

 proposed improvements on Black Swamp consist of a corresponding dredged 

 ditch about 10 miles long with bottom width varying from 13 ft. to 30 ft. 

 Numerous tributaries to both these ditches comprise several miles of both 

 handmade and minimum dredged ditches, as do also several small improve- 

 ments in independent watersheds. 



An estimate of the cost shows the total for the drainage district to be 

 $371,.598, or an average cost per acre of $5.50. 



Mole-draining and the renovation of old pipe drains, D. T. Thring (Jour. 

 Boy. Agr. 8oc. England, 74 (WIS), pp. 76-89, figs. 10).— The process of mole- 

 draining water-logged soils is described and illustrated. Mole-draining is the 

 making of a long hole, from 3 to 4 in. in diameter, under the surface of the land 

 at varying intervals, and at depths from 3 ft. to 18 in., without digging and with- 

 out pipes. The draining tool consists of a 3i in. round steel plug sharp at one 

 end and firmly secured to a steel blade 8 in. wide. A hole is dug to the required 

 depth and the tool dropped into the ground and drawn up the field, thus cutting 

 the earth with the blade to the depth of the plug and leaving a round hole in 

 the clay. 



The best results are said to be obtained on a heavy clay soil and the method 

 is useless unless the subsoil is clay. If old tile drains are already installed the 

 mole-drains may be connected with these where the two intersect. The distance 

 apart of mole-drains is governed by the furrows, but where there are no furrows 

 they should be from 5 to 9 yds. apart. The depth of drains is governed by the 

 soil. On very retentive soils 18 to 21 in. is deep enough, while on lighter clay 

 24 to 27 in. is better. Cost data applicable to English conditions are given, cot- 

 ering the entire process. 



Experiences with wood-stave pipe, E. M. Chandler (Engin. Rec, 69 (1914), 

 No. 11, p. 299). — Information on the use of wood-stave pipe is given as follows: 



For pressure heads between 20 and 150 ft. there seems to be no better type 

 than wood-stave pipe built of redwood or fir. Steel pipe is preferable for pres- 

 sures above 150 ft. on account of the necessarily close spacing of the steel bands 

 on the wooden pipe for high heads. Wood-stave pipe without a preservative 

 coating buried in a dry volcanic ash soil and not under hydraulic pressure con- 

 tinuously is subject to rapid decay. 



Treatment of wood-stave pipe with hot carbolineum is concluded to be bene- 

 ficial. One of the great advantages of having the pipe above ground is the ease 

 of detecting leaks. Draining of the pipes during freezing weather, if they are 

 promptly refilled afterward, can not increase the rate of decay. 



Experience with a machine-banded wood-stave pipe showed that if it were 

 necessary to bury it in arid regions, every precaution should be taken to coat 

 all parts with a proper preservative. 



Country road construction, A. Liebmann (Der Landstrassenhau. Berlin 

 and Leipsic, 1912, pp. 147, figs. 44)- — This book deals with the technical side of 

 road design, construction, and maintenance from the viewpoint of the German 



