172 ' BOOK VI. 



by " rag and chain " pumps. ^^ When there is but a small quantity, it is 

 either brought up in buckets or drawn up by chains of dippers or suction 

 pumps, and when there is much water it is either drawn up in hide bags or 

 by rag and chain pumps. 



First of all, I will describe the machines which draw water by chains 

 of dippers, of which there are three kinds. For the first, a frame is 

 made entirely of iron bars ; it is two and a half feet high, likewise two and 

 a half feet long, and in addition one-sixth and one-quarter of a digit 

 long, one-fourth and one-twenty-fourth of a foot wide. In it there are three 

 little horizontal iron axles, which revolve in bearings or wide pillows of steel, 

 and also four iron wheels, of which two are made with rundles and the same 

 number are toothed. Outside the frame, around the lowest axle, is a 

 wooden fly-wheel, so that it can be more readily turned, and inside the frame 

 is a smaller drum which is made of eight rundles, one-sixth and one twenty- 

 fourth of a foot long. Around the second axle, which does not project 

 beyond the frame, and is therefore only two and a half feet and one-twelfth 

 and one-third part of a digit long, there is on the one side, a smaller toothed 

 wheel, which has forty-eight teeth, and on the other side a larger drum, 

 which is surrounded by twelve rundles one-quarter of a foot long. Around the 

 third axle, which is one inch and one-third thick, is a larger toothed wheel 

 projecting one foot from the axle in all directions, which has seventy-two 

 teeth. The teeth of each wheel are fixed in with screws, whose threads are 

 screwed into threads in the wheel, so that those teeth which are broken can be 

 replaced by others ; both the teeth and rundles are steel. The upper axle 

 projects beyond the frame, and is so skilfully mortised into the body of 

 another axle that it has the appearance of being one ; this axle proceeds 

 through a frame made of beams which stands around the shaft, into an iron 

 fork set in a stout oak timber, and turns on a roller made of pure steel. 

 Around this axle is a drum of the kind possessed by those machines which 

 draw water by rag and chain ; this drum has triple curved iron clamps, 

 to which the links of an iron chain hook themselves, so that a great weight 

 cannot tear them away. These links are not whole like the links of other 

 chains, but each one being curved in the upper part on each side catches the 

 one which comes next, whereby it presents the appearance of a double chain. 

 At the point where one catches the other, dippers made of iron or brass plates 

 and holding half a congius^^ are bound to them with thongs ; thus, if there are 

 one hundred links there will be the same number of dippers pouring out water. 

 When the shafts are inclined, the mouths of the dippers project and are covered 

 on the top that they may not spill out the water, but when the shafts are 

 vertical the dippers do not require a cover. By fitting the end of the lowest 

 small axle into the crank, the man who works the crank turns the axle, and at 

 the same time the drum whose rundles turn the toothed wheel of the second 

 axle ; by this wheel is driven the one that is made of rundles, which 



^^Machina quae pilis aquas haurit. " Machine which draws water with balls." This 

 apparatus is identical with the Cornish " rag and chain pump " of the same period, and we 

 have therefore adopted that term. 



i^A congius contained about six pints. 



