"Springs sometimes communicate with lakes or pools, at higher levels. In such cases, the quantity of water discharged is generally so great, as to form at once a brook or stream of some magnitude. These, therefore, hardly come under the ordinary cognizance of the land-drainer, and are, therefore, here merely referred to." THE WATER OF PRESSURE. Water that issues from the land, either constantly, periodically, or even intermittently, may, perhaps, be properly termed a _spring_. But there is often much water in the soil which did not fall in rain upon that particular field, and which does not issue from it in any defined stream, but which is slowly passing through it by percolation from a higher source, to ooze out into some stream, or to pass off by evaporation; or, perhaps, farther on, to fall into crevices in the soil, and eventually form springs. As we find it in our field, it is neither rain-water, which has there fallen, nor spring-water, in any sense. It has been appropriately termed the _water of pressure_, to distinguish it from both rain and spring-water; and the recognition of this term will certainly be found convenient to all who are engaged in the discussion of drainage. The distinction is important in a legal point of view, as relating to the right of the land-owner to divert the sources of supply to mill-streams, or to adjacent lower lands. It often happens that an owner of land on a slope may desire to drain his field, while the adjacent owner below, may not only refuse to join in the drainage, but may believe that he derives an advantage from the surface-washing or the percolation from his higher neighbor. He may believe that, by deep drainage above, his land will be dried up and rendered worthless; or, he may desire to collect the water which thus percolates, into his land, and use it for irrigation, or for a water-ram, or for the supply of his barn-yard. May the upper owner legally proceed with the drainage of his own land, if he thus interfere with the interests of the man below? Again: wherever drains have been opened, we already hear complaints of their effects upon wells. In our good town of Exeter, there seems to be a general impression on one street, that the drainage of a swamp, formerly owned by the author, has drawn down the wells on that street, situated many rods distant from the drains. Those wells are upon a sandy plain, with underlying clay, and the drains are cut down upon the clay, and into it, and may possibly draw off the water a foot or two lower through the whole village--if we can regard the water line running through it as the surface of a pond, and the swamp as a dam across its outlet. The rights of land-owners, as to running water over their premises, have been fruitful of litigation, but are now well defined. In general, in the language of Judge Story,