i84 BOOK VI. 



to the shaft timbers. This machine draws the water higher, as much as 

 twenty-four feet. If the diameter of the pipes is large, only two pumps are 

 made ; if smaller, three, so that by either method the volume of water is the 

 same. This also must be understood regarding the other machines and 

 their pipes. Since these pumps are composed of two lengths of pipe, the 

 little iron box having the iron valve which I described before, is not enclosed 

 in a trunk, but is in the lower length of pipe, at that point where it joins 

 the upper one ; thus the rounded part of the piston-rod is only as long as 

 the upper length of pipe ; but I will presently explain this more clearly. 



The sixth kind of pump would be just the same as the fifth were it not 

 that it has an axle instead of a barrel, turned not by men but by a water- 

 wheel, which is revolved by the force of water striking its buckets. 

 Since water-power far exceeds human strength, this machine draws water 

 through its pipes by discs out of a shaft more than one hundred feet deep. 

 The bottom of the lowest pipe, set in the sump, not only of this pump but 

 also of the others, is generally enclosed in a basket made of wicker-work, to 

 prevent wood shavings and other things being sucked in. (See p. 183.) 



The seventh kind of pump, invented ten years ago, which is the most 

 ingenious, durable, and useful of all, can be made without much expense. It 

 is composed of several pumps, which do not, like those last described, go down 

 into the shaft together, but of which one is below the other, for if there are 

 three, as is generally the case, the lower one lifts the water of the sump and 

 pours it out into the first tank ; the second pump lifts again from that tank 

 into a second tank, and the third pump lifts it into the drain of the tunnel. 

 A wheel fifteen feet high raises the piston-rods of all these pumps at the same 

 time and causes them to drop together. The wheel is made to revolve by 

 paddles, turned by the force of a stream which has been diverted to the 

 mountain. The spokes of the water-wheel are mortised in an axle six feet 

 long and one foot thick, each end of which is surrounded by an iron band, 

 but in one end there is fixed an iron journal ; to the other end is attached an 

 iron like this journal in its posterior part, which is a digit thick and as wide 

 as the end of the axle itself. Then the iron extends horizontally, being 

 rounded and about three digits in diameter, for the length of a foot, and 

 serves as a journal ; thence, it bends to a height of a foot in a curve, 

 like the horn of the moon, after which it again extends straight out for 

 one foot ; thus it comes about that this last straight portion, as it 

 revolves in an orbit becomes alternately a foot higher and a foot lower than 

 the first straight part. From this round iron crank there hangs the first fiat 

 pump-rod, for the crank is fixed in a perforation in the upper end of this fiat 

 pump-rod just as the iron key of the first set of " claws " is fixed into the 

 lower end. In order to prevent the pump-rod from slipping off it, as it 

 could easily do, and that it may be taken off when necessary, its opening 

 is wider than the corresponding part of the crank, and it is fastened on 

 both sides by iron keys. To prevent friction, the ends of the pump-rods are 

 protected by iron plates or intervening leathers. This first pump-rod is 

 about twelve feet long, the other two are twenty-six feet, and each is a palm 



