424 KANSAS ACADEMY OP SCIENCE. 



danger zone in the ground is in the forfti of a truncated cone with its 

 summit at the surface of the danger source, and its sides falling off at 

 an angle of thirty degrees from the horizontal all around, but at a less 

 and broader angle in the direction of waterflow. The area of safety 

 beyond such a source is not less than 100 feet ; even 150 feet is bet- 

 ter, especially in direction of waterflow, or if the soil be sandy or po- 

 rous. A well in the vicinity of such a source of danger draws the 

 danger toward it, and extends the danger area in that direction. A 

 driven well in such a place is not necessarily unsafe unless the soil 

 should be very porous and the well too shallow, or not remote enough. 

 An open well should have its wall cemented from bedrock up, or at 

 least for eighteen feet from the surface down, so as to exclude all sur- 

 face-water. 



To sum up : Every tree seed contains a chemical laboratory upon 

 a small scale, the capacity of which is increased according to its en- 

 vironments. Water carries, by aid of the ordinary forces of nature, 

 such as surface-tension, cohesion, adhesion, capillarity, and osmosis, 

 under control of temperature and electrical conditions, the food neces- 

 sary for the full development of any tree, and carries it to the spot 

 needed, even to the summit of the tallest tree. The tree itself adapts 

 itself to its requirements and surroundings, thus enabling the water 

 to fulfil its mission. 



