on Rivers and Canals . 597 
regular current in a river is the belt of all means for keep- 
ing it open and deep, and for preventing the formation 
of banks in the bed by the fubfidency of mud, &c. which, 
it does not allow time to precipitate ; I leave it to be con- 
fid ered, whether it is better to have a free and open navi- 
gation fomething incommoded by the ftrength of the 
current, or to have foon no navigation at all, without re- 
peatedly digging the bed anew. 
40. I fhall not here enter into the mechanical part 
of the methods of digging and cleaning canals, rivers, 
and fea ports, or into any defcription of the ma- 
chines and inftruments neceffary for that purpofe. 
The fubjedt would lead me much too far : betides 
all thefe things may be found much at length in 
raoft of the authors who have wrote upon hydraulic- 
architedture, fuch as baratteri, cornelio meyeri, 
guglielmini, and a notorious anonymous French pla- 
giary, who has taken from meyeri, without ever naming 
him, almoft all that is contained in his book, publitlied 
at Paris in 1693, and at Amfterdam in 1696, in odtavo, 
under the title of Fraits des Moyens de rendte les Rivieres 
navigables. But the author who has treated this fubjedt 
with the greateftcare, and moffc at length, is the celebrated 
belidor, in his Architecture Hy dr antique, 4 vol.in quarto. 
To thefe may be added a late memoir of M. forfait of 
Vol. LXIX. 4 1 Rouen, 
