CHAPTER XIX.. Drainage of Stiff Clays.

DRAINAGE OF STIFF CLAYS.

Clay not impervious, or it could not be wet and dried.--Puddling, what is.--Water will stand over Drains on Puddled Soil.--Cracking of Clays by Drying.--Drained Clays improve by time.--Passage of Water through Clay makes it permeable.--Experiment by Mr. Pettibone, of Vermont.--Pressure of Water in Saturated Soil.