404 



APPENDIX. 



surface of clay or other impervious matter ; the lower 

 springs at C always running, those at B generally, and 

 those at A when the ground is very wet. D is the main 

 drain or outlet falling into a rivulet R, as seen in the 

 plan. 



After having examined all excavations near the place 

 to be drained, such as quarries, ditches, beds and sides of 

 rivers, and sunk wells, and thereby ascertained the na- 

 ture of the different strata below the soil, the surface of 

 the ground in question, and the nature of the plants, will 

 shew where springs arise ; and from other observations, 

 or from measurement, it may be ascertained what is the 

 angle of descent which the open porous soil makes with 

 the clay soil. 



From these observations, when circumstances permit, 

 a great saving may be made, by making a ditch of suffi- 

 cient size in the line CCC, and boring with an auger, 

 as pointed out on that line, into the tail of the gravelly 

 subsoil. The water finding easier vent through the 

 auger holes at the lower elevation, will flow through 

 them alone, leaving the springs at AA, BB and CCC 

 completely dry. 



It is the pressure of the water above the level of the 

 main drain that causes the water to spring. Any person 

 who may have paid attention to digging wells, must have 

 observed, that after cutting through an impervious soil, 

 and entering into gravel, sand, or chinky rock, the water, 

 if any, naturally rises to some certain height, correspond^ 



