ig6 



BOOK VI. 



The fifth pump of this kind is partly like the third and partly like the 

 fourth, because it is turned by strong men like the last, and like the third 

 it has two axles and three drums, though each axle is horizontal. The 

 journals of each axle are so fitted in the pillows of the beams that they cannot 

 fly out ; the lower axle has a crank at one end and a toothed drum at the 

 other end ; the upper axle has at one end a drum made of rundles, and at 

 the other end, a drum to which are fixed iron clamps, in which the links of a 

 chain catch in the same way as before, and from the same depth, draw water 

 through pipes by means of balls. This revolving machine is turned by two 

 pairs of men alternately, for one pair stands working while the other sits 

 taking a rest ; while they are engaged upon the task of turning, one pulls 

 the crank and the other pushes, and the drums help to make the pump turn 

 more easily. 



The sixth pump of this kind likewise has two axles. At one end of the 

 lower axle is a wheel which is turned by two men treading, this is twenty- 

 three feet high and four feet wide, so that one man may stand alongside 

 the other. At the other end of this axle is a toothed wheel. The upper 19 

 axle has two drums and one wheel ; the first drum is made of rundles, and to 

 the other there are fixed the iron clamps. The wheel is like the one on the 

 second machine which is chiefly used for drawing earth and broken rock 

 out of shafts. The treaders, to prevent themselves from falling, grasp in 

 their hands poles which are fixed to the inner sides of the wheel. When 

 they turn this wheel, the toothed drum being made to revolve, sets in motion 

 the other drum which is made of rundles, by which means again the links 

 of the chain catch to the cleats of the third drum and draw water through 

 pipes by means of balls, from a depth of sixty-six feet. 



But the largest machine of all those which draw water is the one which 

 follows. First of all a reservoir is made in a timbered chamber ; this reser- 

 voir is eighteen feet long and twelve feet wide and high. Into this reservoir 

 a stream is diverted through a water-race or through the tunnel ; it has two 

 entrances and the same number of gates. Levers are fixed to the upper part 

 of these gates, by which they can be raised and let down again, so that by one 

 way the gates are opened and in the other way closed. Beneath the openings 

 axe two plank troughs which carry the water flowing from the reservoir, and 

 pour it on to the buckets of the water-wheel, the impact of which turns the 

 wheel. The shorter trough carries the water, which strikes the buckets 

 that turn the wheel toward the reservoir, and the longer trough carries 

 the water which strikes those buckets that turn the wheel in the opposite 

 direction. The casing or covering of the wheel is made of joined boards to 

 which strips are affixed on the inner side. The wheel itself is thirty-six feet 

 in diameter, and is mortised to an axle, and it has, as I have already said, 

 two rows of buckets, of which one is set the opposite way to the other, so 

 that the wheel may be turned toward the reservoir or in the opposite 



19 In the original text this is given as " lower," and appears to be an erroi. 



