38 SMALL WATER SUPPLIES. 



tools is as follows. A small hole is cut, say 3 ft. deep, 

 for a start, in which a length of pipe of the largest 

 size proposed to be used is inserted as a guide for the 

 tool, the pipe being carefully set in its true position 

 in a secure manner and truly vertical. Next, shear 

 legs must be obtained, preferably of a light 

 iron collapsible form, and a pulley slung 

 vertically over the tube. Over this a rope 

 passes, and to which the tools are attached. 

 The working of the tools simply consists of 

 moving the tools up and down by means 

 of the rope. The chisel tool will then cut 

 and break up the rock gradually, which has 

 to be removed by an apparatus known as 

 the shell pump. It is illustrated in fig. 19. 

 This is a simple piece of apparatus, consist- 

 ing of a steel tube having a rubber foot 

 valve. By being raised and lowered into 



the rubbish a couple of times, it gets filled 

 FIG. IQ. i-i ..u 



very much in the same manner as the 



ordinary lift pump. It is then drawn up and 

 emptied. A similar form of apparatus is shown 

 in fig. 20 with a ball valve and seat. Notice should 

 be taken of the small pin which limits the rise of 

 the ball. Figs. 21, 22, and 23 show special varieties 

 of chisels for specific purposes. Fig. 21 is for use in 

 hard gravel and rock ; fig. 22 for breaking up boulders 

 of hard rock encountered in boring in clay, with the 

 apparatus shown by fig. 18 ; while fig. 23 is a simple 

 V-shaped chisel. They are made of tool steel. 

 Fig. 22 is sometimes called aping drill. Sometimes, 

 unfortunately, tools break and their removal is 

 occasionally difficult. In figs. 24 and 25 is illus- 



