ON ROMAN AQUEDUCTS*. 



THE aqueducts by means of which Rome was supplied 

 with water are in many points of view interesting, not only 

 from the magnificence of their construction but also from the 

 problems which they suggest respecting the scientific knowledge 

 possessed by those who originally formed or subsequently ma- 

 naged them. The accounts which have come down to us with 

 respect to the water supply of Rome are unsatisfactory* The 

 treatise of Frontinus is the most detailed, and, on that account 

 perhaps, the most disappointing. We find in it a great deal of 

 information with respect to the sizes of the pipes by means of 

 which the distribution of water took place, but that is nearly 

 all ; and, as .Prony has remarked, the fulness of details on this 

 matter makes the total silence on another not less important 

 appear more strange than it otherwise would do; I mean the 

 depth at which the pipes were placed below the level of the 

 surface of the water in the reservoirs. To this remark we may 

 add, that there is no estimate of the amount of water which in 

 a given time was actually received through a pipe of given size. 

 Prony is of opinion that a general rule must have prevailed, 

 and that pipes of all sizes must have been inserted at the same 

 depth, because we find it assumed that the discharge was pro- 

 portional to the area of the section. The inference being natural, 

 the same writer is of opinion that the notions of Frontinus, 

 who of course knew all that was known in his time, were ex- 

 ceedingly unscientific, and it is difficult to see how this can be 

 denied considering the account he gives of the attempts he made 

 .to gauge the different aqueducts, I cannot attempt to enter 



* Now first published. 



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