so TRANSACTION'S OF THE [jAJST. 31, 



it is apparently, in most cases, because they have not been sunk 

 deep enough to reach those water-bearing beds of gravel and 

 sand from which a perpetual and continuous supply might be 

 obtained. The farmer, in sinking a well, looks gratefully for 

 the first indication of water, and as his needs are not excessive, 

 the sinking of the well is stopped when the upper surface of the 

 first ter-bearing stratum is reached. The methods and appli- 

 ances at his command do not permit him to sink deep into 

 watery ground. 



The "driven well" goes deeper, and the tube is easily driven 

 through soft ground to any desired depth ; while the artesian 

 boring proper pierces the solid strata still lower, if necessary, 

 and draws its waters from sources more distant than those which 

 supply the common or the driven well. 



The joroportion of the rainfall which passes off by the surface 

 streams is so variable in different jDlaces that actual gauging of 

 the streams is generally necessary to determine it. Over a large 

 portion of our Northern States, this proportion is from 30 per 

 cent to 90 per cent of the rainfall, depending upon the seasons, 

 the surface topography, and the geological characteristics of a 

 district. From 10 per cent to 70 per cent of the rainfall for 

 the same localities disajjpears, being absorbed by plants, or re- 

 cvaporated from the surface, or sinking beneath it, and of this 

 latter portion there is no doubt that, in many parts of our coun- 

 try, nearly all follow shallow sub-surface channels slowly to the 

 sea-levels. 



Artesian wells have become so common in every quarter of 

 the globe as no longer to excite especial interest, beyond that 

 which may be attached to the great depths of some and the 

 large volume of flow from others. As a general rule, the hard or 

 consolidated strata of the earth's crust have to be pierced, often 

 at very great depths, to reach water-bearing strata which have 

 been pointed out by precise geological knowledge, or which are 

 sought for with much expense and uncertainty where such 

 knowledge is wanting. 



"While the mechanical processes of boring these wells have 

 reached such a degree of excellence and certainty that indi- 

 viduals or companies may now be found ready to undertake for 



