190 BOOK VI. 



of a palm, that it may be able to take the end of the pipe which 

 follows. And each length of pipe is fixed with iron clamps to the timbers of 

 the shaft, that it may remain stationary. Through this continuous series 

 of pipes, the water is drawn by the balls of the chain up out of the sump as 

 far as the tunnel, where it flows out into the drains through an aperture in 

 the highest pipe. The balls which lift the water are connected by the iron 

 links of the chain, and are six feet distant from one another ; they are made 

 of the hair of a horse's tail sewn into a covering to prevent it from being 

 pulled out by the iron clamps on the drum ; the balls are of such size that 

 one can be held in each hand. If this machine is set up on the surface of 

 the earth, the stream which turns the water-wheel is led away through open- 

 air ditches ; if in a tunnel, the water is led away through the subterranean 

 drains. The buckets of the water-wheel, when struck by the impact of the 

 stream, move forward and turn the wheel, together with the drum, whereby 

 the chain is wound up and the baUs expel the water through the pipes. If 

 the wheel of this machine is twenty-four feet in diameter, it draws water from a 

 shaft two hundred and ten feet deep ; if thirty feet in diameter, it will draw 

 water from a shaft two hundred and forty feet deep. But such work requires 

 a stream with greater water-power. 



The next pump has two drums, two rows of pipes and two drawing- 

 chains whose balls lift out the water ; otherwise they are like the last pump. 

 This pump is usually built when an excessive amount of water flows into the 

 sump. These two pumps are turned by water-power ; indeed, water draws 

 water. 



The following is the way of indicating the increase or decrease of the 

 water in an underground sump, whether it is pumped by this rag and chain 

 pump or by the first pump, or the third, or some other. From a beam which 

 is as high above the shaft as the sump is deep, is hung a cord, to one 

 end of which there is fastened a stone, the other end being attached to a 

 plank. The plank is lowered down by an iron wire fastened to the 

 other end ; when the stone is at the mouth of the shaft the plank 

 is right down the shaft in the sump, in which water it floats. This 

 plank is so heavy that it can drag down the wire and its iron clasp and 

 hook, together with the cord, and thus pull the stone upwards. Thus, as 

 the water decreases, the plank decends and the stone is raised ; on the 

 contrary, when the water increases the plank rises and the stone is lowered. 

 When the stone nearly touches the beam, since this indicates that the water 

 has been exhausted from the sump by the pump, the overseer in charge of the 

 machine closes the water-race and stops the water-wheel : when the stone 

 nearly touches the ground at the side of the shaft, this indicates that the 

 sump is full of water which has again collected in it, because the water raises 

 the plank and thus the stone drags back both the rope and the iron wire; 

 then the overseer opens the water-race, whereupon the water of the stream 

 again strikes the buckets of the water-wheel and turns the pump. As 

 workmen generally cease from their labours on the yearly holidays, and 



