634 -Mr. mann’s 'freatife 
which give motion to thofe before them by their weight 
and impulfion. Without this the refiitance proceeding 
from the bottom and fides of the bed, and from other 
accidental obftacles (N° a i .) would equal, if not furpafs, 
the ordinary caufes of acceleration (N° 20) fo as to dimi- 
nifh continually the motion of the waters, and at laft 
render them almoil ftagnant (N° 22.). But nature has 
prepared remedies againll this, as we have feen above 
(N° 28. 29. 48.). What RicciOLi ,l> fays of the Po y in 
that part of its courfe next its mouth, is perfectly con- 
formable to this theory : “ Sic Padus, qui a Pago Q tlellata 
w vocato, ufque ad Adriaticum , intervallo milliarium cir- 
i( citer 70, non habet libramentum majus 13 aut 14 
u pedum, ita ut lingulis milliaribus ne 3 quidem unciae 
a declivitatis obveniant ; unde Padufa, potius inftar ftag- 
nantibus aquis, incertiffimus effet ad defluxum curfus : 
tc impetu tamen impreii'o a 30 et amplius fluminibus 
a aut torrentibus fe in ilium exonerantibus, etiamque a 
“ nativae pondere aquae ex fuperioribus et altioribus 
a prope Alpes alveis decurrentis, velocitatem max-imam 
u acquirit.” 
73. From many obfervations and trials which I made 
for this purpofe in the years 1773 and 1774 upon the 
river Iprelee in Flanders, which comes down from the 
(!) Geogr. et Hydrogr. 4 . VI. c. xix. p, 215. edit. Bonon. 1661. 
city 
