TUBE WELLS. 



the writing' acting as the negative ; and if ink be first run over "it; as in 

 a stencil plate, by a proper " roller," the latter will come out as plainly, as 

 possible. 



TUBE WELLS. 



The principle upon which the tube well depends is very simple. It is 

 well known that in certain localities water lies a short distance beneath the 

 surface of the ground, and a very little trouble would satisfy us upon the 



Fig. 483. Peneumatic pencil. 



point, and render us quite independent of the water companies' supply. On 

 the supposition that the water exists underneath our garden at, say, twenty- 

 five feet beneath the surface of the ground, we have only to drive into the 

 soil a tube for that distance, and by the assistance of a common pump we 

 shall obtain a pure supply of water. 



We will now proceed to describe the manner in which these wells are 

 sunk. The first step is to fix a platform firmly upon the ground and bore a 

 hole, by which the tube is to enter the ground. This tube should be very 



