[ 3§4 ] 
the faid effect will be greateft when there is only 
one float-board placed vertically, and lead: when 
their number is infinite : let us enquire what it will 
be in this latter cafe. We will fuppofe the fame 
fig. 5, and the fame denominations as in § VII. We 
had CO = we fhall have (neglect- 
ing dx \ dx\ and dx 4 ) aa — CQ — 2 *. ec ? x , 
a — X 
CO 
j a. ' — CO Actctd X -\T .1 r 
, and — ± . Now the pref- 
« cc 
fure on OM is, by § II 
n $ a. — ( 
T T A /y /v ' 
120 ««■ 
CO 
+ i. 33 
VV ( aet 
4 C O ') 
•* —J 
a* ^ 
-CO)-S2.i 
3 
which (by putting for C O its value) will become 
(2 c&dx — 2 xdx) (v — z~) whofe integral 
»/? 
120 
*9 
(2 ccx — x x) (v — 
n@ (v — z 7 ) 
120 ' ' 1 x 120 
(making x r= a. — f) will exprefs the efleCt re- 
fulting from an infinite number of float-boards : this 
lead effeCt will be to the greated, that is when 
there is but one float-board, as ( v — z~) : vv — 
* 4 - 4- — (act 4 - //) or as (a; — x ) 
3 » 0 , 0 . — jf I a a « ' ' JJ J \ / 
: 4. vv - i zz. (~r-J §• VI. 
This ratio will be that of 1 : 2 iff = o 
1:1,485 f = la 
1 : 1 f =■ * 
§X. If 
