An Account of ibme Books. 
I. ME CHA NIC A, Jive De MO 7 V I'raSfatus Geometrkm 
PARS SECVNDA'^ iftqua^ De CENT RO GRA FITATIS 
Ejnfque CALCVLO: Autk Johanne Wallis, SS, Tk 
Geometrm Profejf. Savilimo in Celeberr, Acad,Oxof^^ef?fi^ 
Regalis Societ, Sodaliy ^ Regime Majefiati i Sacris. ten- 
dim ^ Impenjis Mofis Pitt in Fico vovato Little Britain^ 
1670. in 4*. 
IN t\i\s Second Part (amongfl: many other things , in this 
and the foregoing Part, Demoajirated ^ which are 
wont to be Pojlulated^ but (hould be Proved the Excel* 
lent Author demonjlrates the Center of Gravity to ie(which 
hath not been done formerly , that we know of 5 by any 
and that, as to all Fonderaiion ^ the wkok weight may juftly 
be reputed There to he^ where is its Center of Gravity ^ and 
fo much to be mov'd : with other general AffeBiom there- 
of. He (hews alfoj from General PiincipleSj H0W5 by Cal- 
culatiooj to determine, ss well the Magnitude^ as the Cen- 
ter of Gravity^ in innumerable forts of Lines , Surfaces^ and 
Solids^ (and the Aggregates or Differences of fiich. ) As , in 
^\\ Right-lined Figures whatfoever 5 in ail Solids hounded by 
TlainS'^ in C<?«e/ alfo and Cylinders: And m Curve- lined 
Figures innumerable ^ not only ( with Archimedes ) in the 
Parabolar Figure, but like wife in al! Paraboloeids whatever 
(and th^ parts offuchO together with their VnguUr So* 
lids infifting on them 5 and thdv Conoeids or other Solids 
made by the Converfton ( perfeftj orimperfeft, ) of thofe 
Plains (or their Parts) about any Axe in the fame Plain af- 
figned ; and the Center of Gravity of all thefe Solids, And 
the like alfoin other Figures Reciprocal to thefe Parabolo- 
eids, infinitely continued between fuch Curves and their 
Afymptotes : Shewing , which of thofe Figures ( irrjinitely 
Long) are of Ftnit magnitude, (and what th-4t is ^ ) which» 
oi Infinite and, which of them have, which have not ^ 
Centers of Gravity'-^ and , in thofe which have 5 how to AP 
fign them: And the like of the Vnguls appertaining to 
R. 2 ihemj 
