(I 692 ] 
ifiapds ia the middle of rivers, eddies and whirlpools, p. 607. Inconveniences of 
diminifhing the velocity of the current, by widening the canal, and method of 
obviating thofe inconveniences, p. 608. Nature of inundations, and manner of 
their formation considered, p. 609. On the confluence of rivers, and on the repa- 
ration of the fame river into divers branches or mouths, with the effedls thereof on 
the velocity of currents, inundations, See, p. 61 1. Great rivers receive many 
others into their beds, p. 612. This confluence ufeful for many purpofes, ibid. 
One river may fall into another of equal magnitude with itfelf, and yet the fe&ion 
of the current in the common bed, after their confluence, be no more than it was in 
each before their jun&ion, p. 613. How to diminifh the danger of an overflow, oc- 
casioned by the tides, wind, and rolling in of the fea at the mouths of rivers, 
p.614. Advantages of fluices for thefe purpofes, p. 6rfi>. Which, however, arc 
only ufeful when there is a Sufficient abundance of water in the rivers to fill the new 
beds and channels, fo as to prevent the velocity of the currents therein from being 
notably diminifhed from what they were before the divifion, p. 618. Laws of the 
meeting of oppofite currents, with the application of them to fluices, p. 619. 
Sluices need be fhut only a quarter of- an hour before the flood has rifen to the level 
of water in the canal, p. 62r. Experiments to determine the different velocities 
in -different depths of water of the fame floating body, moved uniformly by an equal 
force, p. 622. Dr. Franklin’s experiments on this fubjett, repeated on a larger Scale, 
with an account of the mechanifm of the inflruments ufed, p. 624. Table of the 
experiments, p. 629. And remarkable concludon from the mean refults of them, 
p. 630. On the quantity of declivity in rivers, p. 630. Principles to prove that 
the declivity and velocity of a river are lefs in proportion as the bed approaches 
nearer to being concentrical with the curve of the earth’s Surface, p. 633. The real 
quantity of declivity, in different rivers, determined as nearly as poffible, ibid. 
Table of comparative proportions between the declivities and velocities in different 
kinds of rivers, p. 640. All the rivers in the world clafled, p. 641. General view 
of the elevation of continents along the principal rivers of the known world, p.654. 
Rulandus. Cauk wetted with antimony has appearances of his falfe# liver of anti- 
mony, p. 19. 
Ruffians* how they treat perfons affected by the fumes of burning charcoal, and fimilar 
effluvia, p.324. Ruflian-houfes, how heated, p. 327, 
S. 
Salt. Sal ammoniac produced by clays diddled with fea-falt, p. 21. Glafs, in which 
there is much alkaline fait, lefs fit for ele&ricity than others, p. 66£, 
Salt~ 
1 
