ARTESIAN WELLS. 235 



may in many cases prohibit the improvement. But it 

 cannot always thus remain. The exigencies of a rapidly 

 increasing population will sooner or later compel a differ 

 ent system of agriculture ; there must be more enterprise, 

 a greater employment of capital, new methods of pro 

 ducing food, and compelling the soil to yield its maximum 

 crops. One of the improvements will surely take the 

 shape of equalizing the supply of water. There is an 

 extensive scope for profitably doing this now, if we will 



. -v, ;\ 



Fig. 119. RESERVOIR IN A HOLLOW. 



only make the most of what opportunities we have. 

 There are numberless farms through which, every Spring, 

 a flood of water pours from the ground upon a higher 

 level. Numberless streams are torrents in Spring and dry 

 gullies in the Summer and Fall. By individual or associ 

 ated effort, reservoirs more or less capacious, might be 

 made to catch all this useless or injurious water, and 

 make it serve a useful purpose. 



ARTESIAN WELLS. The operation of an artesian well 

 may be explained by the illustration, fig. 120. In this 

 is shown a basin-shaped deposit of various strata, either 

 of rock or of clay, gravel or sand, resting one upon 

 another. One of these strata consists of porous material, 

 lying between two impervious strata ; it may be that the 

 one consists of sand or gravel, lying between two beds of 

 clay, or it may be of fissured sandstone, or limestone, 

 placed between two beds of compact rock. At the outer 

 edge of the basin these strata reach the surface. The 

 softer materials being easily worn away, may form valleys 

 through which streams may flow, and a large portion of 

 their contents may escape down the porous bed until the 

 basin is filled. In some cases, when streams are thus 



