ELASTICAE ET GRAVIS, 79 



AMB. Irruat ventus fecundum TM parallelam axi 



AP. Erit eius vis , qua in curuam normaliter agit 



2 

 vt quadratum finus anguli AMT id eft: vt ^ pona- 



2 



ds 



tur itaque^N— ^jhabebitur t^^-l- ardx -\- ayds 

 —Qds. Cum autem fit ^— ^ erit dy"^ -|- adsdydx 

 ^aydsddx—Cdsddx. Eft autem ddx~-=^y^y ergo 

 dy'^dx-\-adsdx-—aydsddy-{-Cdsddy—o ponatur dszn 

 pdy; erit ddy—M^ et dx—dy V/)/) — i. Vnde erit dy 

 ^pp- 1 -\- ^pip^ 'dy zz cdp-aydpjfm -^ =: 



^-? wSit Vpp-i zz: p — a ; erit -^^ = 



ri+2^ refoluatur ^qq-\-a-aq^ in duos fado- 



res x-\-^qq tt a-\-Bqq\Mhi eft(3=|--i-y(^-M) et 

 B—^-'\\A--\-aa). Et hinc erit Jy^—JM^ -{- mdg , 

 vbi ;«— n±^=-2lid=.?5l et «— i-il^(+±^'. Eritigitur 

 -i/(^-^j)rz 5^^ /(i -\-^qq) -\- i, Ka H- ^qq) — 



*-U I -f-P^^J-^-Z^a-f-yq ^) — 1_ ] al^aqq{ g— v(4-f-c a )) ^n. ^., 



V4._j.aa V(4-l-aaJ a-+-<M:-t-VC'H-aaJ, 



tem q—p-Vpp- 1 — ^^vnde habebitur(^'')''''^"*'°''^'' 



ady ^(ds—dx) (2.4-v.t-4- aa) pj-Q vekria graui. 



2 2 



ed^» H-(dy — dx) (2-V4-*-aa) 



Si ventus incidat deorfum iuxta TM , erit eius Fig. i©, 

 vis in velum vt quadratum finus anguli AMT :id efl: 



o 2 2 



vt **— . Ponatur igitur 0^=:-"^ habebitur ^^ -+- 



ds 



ardx-\-ayds:=:zCds. Quia autem ''— -^^; ent ^.r^^ 



/ 



