682 bepobt— 1878. 



greater than the average fall of the aqueduct ; and thus they allowed the water to 

 take the hydraulic mean gradient due to the head necessary for the delivery of the 

 water. It is probahle that these " suterasi " were made about 1000 a.d. 



For 400 or 500 years after the last date very little was done in the way of great 

 public works of this description ; and it was not until the beginning of the sixteenth 

 century that the state of the rivers in Italy commanded the attention of the great 

 landowners and scientific men of that country. At that time, chiefly in consequence 

 of the appointment of a Commission in 1516 by Francis I., works for remedy- 

 ing existing evils were seriously thought of ; and for a long series of years the most 

 eminent mathematicians and engineers were engaged in investigating the subject 

 and in designing and carrying out works of greater or less magnitude. A very full 

 collection, both of the writings of these Italian engineers and of descriptions of 

 their works, is contained in a book of thirteen volumes, published at Bologna, in 

 1821-24, entitled ' Raccolta dAutori Italiani che trattano del Moto dellAcque.' 

 It would seem that about the same time the question began to excite interest in 

 England, for it was in the reign of Henry VIII. that a public statute first 

 dealt with river conservancy. But it is to be remarked that neither in Italy nor 

 in England was the question treated in anything like an exhaustive manner. The 

 great hydraulic works of Italy relate almost exclusively to irrigation and naviga- 

 tion, whilst the drainage of lands and the prevention of floods were the objects of 

 legislation in England. During the same period the Dutch were of course con- 

 structing many important hydraulic works ; but these, from the special circum- 

 stances of the country, were not such as to have much bearing on the general 

 question of the conservancy of rivers. 



After the drainage of the Fens, the next great works in England were the 

 canals, which, in a very few years, extended over the whole of England, and 

 formed a complete system for the conveyance of traffic. It is superfluous to say 

 that their construction and maintenance had a strong bearing upon the regulation 

 of rivers. The well-known saying of Brindley that rivers were " principally valu- 

 able for feeding canals " sufficiently indicates the subserviency of the other in- 

 terests involved. Next, the introduction of railways and steamboats, and the 

 increase in the size of ships, turned the attention of those interested in rivers to 

 the improvement of the tidal harbours and channels ; and from that time to the 

 present the greatest hydraulic works of our time have been connected with navi- 

 gation. The concurrent increase in manufactures necessitated the employment of 

 water in ways apparently antagonistic to other interests, and introduced the new 

 element of pollution of our rivers and streams, whilst the demands of sanitary 

 legislation consequent on the great increase of population made it imperatively 

 necessary that their purity should be maintained. Indeed, we may say that the 

 present high state of civilization in which we live has involved greater complica- 

 tions in this as in other departments of life, and requires special arrangements 

 to meet them. 



Legal enactments for the regulation of rivers, and for defining the rights of pro- 

 perty in water, have existed from very early times. Solon laid down that to inter- 

 cept the supply or to corrupt the quality of water is a crime. He also enacted that 

 if any one dug a well to a depth of ten fathoms (opyvlai) without finding water, he 

 should be permitted to take from his neighbour's well a pitcher of six x°f s (about 18 

 quarts) twice a day. Plato, in his Laws, mentions an analogous provision, but con- 

 fines it to drinking water only. Another law quoted by him is more to the point : it 

 runs as follows : " If after heavy rains any of the lower riparian proprietors should 

 injure a neighbour who lives above them, by stopping the downward flow of the 

 water, or in case, on the other hand, the proprietor living higher up shall injure his 

 neighbour below, by negligently allowing the water to run down upon him, either 

 of them may call in the magistrates and obtain a decision for the guidance of both 

 parties. If either party fail to abide by such decision, he shall be punished for 

 the enviousness and peevishness of his spirit, and shall pay double damages to the 

 injured person." 



The Pandects of Justinian, which area collection of all the old legal authorities 

 of Roman Law, analogous to our own Reported Oases, contain a variety of leading 



