(^8) 
wehcitati mobilis in r?$a M&^ipfi AD tquali, & ides eodem tem- 
pore perficitur utraque retfa AD ; AB 5 cr proinde eodem tempore 
ferficiuntur accefsiones ad plana re ft (tent ia AB, AH $ ideeque velo- 
citates accefsionum ad plana refiftentiafunt in direfta ratione AE ad 
AH, at que ideo percufsio in puntto D. eft ad percufsionem in punEio 
C.ineadem ratione AE ad AH 5 nempeut Sinus anguli incident 1 a 
ADE. ad ftnum anguli incidenti* ACE, vel AFE. guoniam 
mtemre£t<z hC^AF^ <equaliter inclinant ad planum CF, mobilia 
in rettis AC, AF ; accedunt ad planum CF, in eadem froportione 
qua movent ur in reft is AC, AF5 & ideo percufsio in C e[t ad 
percufsionem in F in ratione velocitatis mot us in AC feu in AD ad 
velocitatem motus in AF $ At demonflratum ejl ante, percufsionem 
in punfto D ad percufsionem in puncio C^effe in ratione finus an- 
guli ADE ad [mum anguli AFE, & nunc demonftratum eft, per- 
cufsionem in puntto C efle ad percufsionem in punBo Y^ut velocity 
motus in AD ad velocitatem motus in AF. Igitur ex 5 ,defin. 6.Ele- 
mentorum, percufsio in D, eft ad percufsionem in F,/» ratione eompe- . 
fit a ex ratione finus anguli incidentU ADE, ad [mum anguli inci- 
dents AFE, & ex ratione velocitatis in AD ad velocitatem in AF5 
<juod demonftrare oportuit. Neminem moveat, quod h&c demon- 
fir atio adftritta fit motibus aqualibus in lineis rettis & plants re- 
ftftentibus $ eft enimverainomnicafu: nam,cumpercufsimes fiant 
in pun&o, in hoc coincidunt rettum, curvum, tquale, & in&quale $ 
ft autem in punBis per cuf stones non fiant 9 de i/lis non pot eft dari con- 
sider atio geometric a> fedjudicandus eft conch ftonis defe&us Secun- 
dum defcttummaterU a conditionihus requifitis, ficut femper fieri 
debet , dum demon fir at tones geometric* corpori phyfico appli- 
cant vr. 
In Angeli his reply to Manfreddi, he maketh mention of an 
Experiment, which (as was related to him by a Srvedifk Gentle- 
man) had been made with all due circumfpe&ion by Carte fius to 
prove the Motion of the Earth. The experiment was 5 Hecaufed 
to be ere&ed a Canon perpendicular to the Horizon 5 which be- 
ing 24 times difcharged in that pofture, the Ball did fall 22 times 
towards the Weft, and only twice toward the Mafi. 
An 
