REPORT ON HYDRAULICS. — PART II. 427 



from one level of a river or canal to another, that a new career 

 was opened out to hydraulic architecture. By this beautiful 

 contrivance all the difficulties attending navigation were over- 

 come, rivers were rendered navigable, or avoided where too rapid 

 or too dangerous, whilst the irregularities of the surface of a 

 country were compensated. 



The two canals which communicate to the Tecino and Adda 

 rivers, and which were afterwards united at Milan by the cele- 

 brated Leonardo da Vinci about the end of the 14th century, 

 were remarkable for the first application of a series of locks to 

 any canal. The Naviglio Grande, made in the 13th century, 

 from the Tecino river to Milan, was undoubtedly the first canal 

 with a lock. In contemplating these works in the year 1827, 

 the words of that excellent writer on hydraulics, Paul Frisi, 

 naturally occurred to us, " lo no getto mai gli occhi sopra questi 

 navigli senza un interno sentimento di stima verso que gl' Ulustre 

 architetto chevi seppero vincere tante difficolta*." 



From this epoch may be dated the progress of Italy generally 

 in the practice of hydraulic architecture. In the year 1516 a 

 commission of scientific men was appointed by Francis the First 

 to examine and consider the actual state of the canals then ex- 

 si chiamano Maestri di Orologio, faranno che le barche e i burchi pvotranno 

 passare per la chiusa de Stra senza pericolo, operando in modo, che le acque 

 usciranno confacilita, senza esser obligate a scaricare, e senza essere tirate," &c. 



Antonio Lecchi, in his treatise on Navigable Canals, pronounces the inven- 

 tion of the lock to have taken place in the year 1420, because an early writer, 

 Pietro Candido Decembrio, in his Life of Duke P. M. Visconti, says, " Meditatus 

 est et aquae rivum, per quem ab Abbiate ad Viglevanum usque sursum veheretur, 

 aquis altiora scandentibus, machinarum arte, quas Conchas appellant." 



Antonio Lecchi further says, that about the year 1188, Pitentino, an archi- 

 tect of Mantua, had constructed a lock at Governolo, on the river Mincio, to 

 render it navigable, and that many remains of locks existed on several of the 

 Italian rivers anterior to the year 1188. Paul Frisi, referring to the expression 

 of Visconti, says, it only meant a regulator of the surface of the water, and not 

 a lock. An anonymous Italian writer, in the year 1825, on the canal of Bologna, 

 gives the discovery to Albert! in the year 1452- In the ten books of Alberti's 

 Architecture the following sentence occurs, " Duplices facito clausuras, secto 

 duobus locis fiumine spatio intermedio quod navis longitudinem capiat, ut si 

 erit navis conscensura cum eo applicueiit inferior clausura occludatur, aperiatur 

 superior: sin autem erit descensura, contra claudatur superior aperiatur inferior, 

 navis eo pacto cum ista parte fluenti evehetur fluvio secundo." Lastly, Bru- 

 sehetti, in his account of the progress of the interaal navigation of the Milanese, 

 says, that the first lock {conca) was erected at the commencement of the 15th 

 century at Viarenna, and that the honour of this invention was due to two 

 engineers of the Grand Duke Philip of Modena, named Orgagni and Fioravantc, 

 and not Leonardo da Vinci, who did not flourish until a century after. The name 

 conca was given to the lock in consequence of its having been constructed for the 

 purpose of transporting the stones intended for the Cathedral or Duonio of Milan. 



• De Canali Navigabili, Traltato del P. D. Paoli Frisi : Firenze, 1770. 



