( 14 ^ ) 
the Ratio Modularis defined above,) as the difierencc 
of thofe Altitudes is to the aforefaid given Altitude of 
the homogeneous Atmolphsere. 
He concludes the Logometria with a General Scho- 
lium^ containing great Variety of elegant Conftru- 
d:ions both Logometrical and Trigonometrical ; fuch 
as give the Length of Curves either Geometrical or 
Alechanical ; their Area’s and Centers of Gravity ; 
the Solids generated from them, and the Surfaces of 
thefe Solids ; together with feveral curious Pro- 
blems in Natural Philofophy, concerning the At- 
tradlion of Bodies, the Denfity and Refiftance of 
Fluids, and the Trajed:ories of Planets. Several of 
thele Problems have two Cafes ; one conllru6ted by 
the Meafure of a Ratio, and the other by the Meafure 
of an Angle. The great Affinity and beautiful Har- 
mony of the Meajures in thefe Cafes, has given occa- 
fion to the Title of the Book. Tlie Meafures of 
Angles arc defined (jufl as the Meafures of Ratio’s) to 
be Quantities of any Kind, whole Magnitudes are 
analogous to the Magnitudes of the Angles. Such may 
be the Arcs or Sed:ors of any Circle, or any other 
Quantities of Time, Velocity, or Refiftance, analo- 
gous to the Magnitudes of the Angles. Every Sy- 
ftem of thefe Meafures has likewife its Modulus homo- 
geneous to the Meafures in that Syftem, aud may be 
computed by the Trigonometrical Canon of Sines and 
Tangents, jufl as the Meafures of Ratio’s by the Ca- 
non of Logarithms ; for the given Modulus in each 
Sy flem bears the fame Proportion to the Meafure of 
any given Angle, as the Radius- Circle bears to an 
Arc which fubtends that Angle, or the fame as this 
conflant Number of Degrees 5'7,i95'7795'i 30 bears to 
the Number of Degrees in the faid Angle. Upon the 
whole our Author thus expreffeshimfelf, /• 35 - “ Fx 
“ addud:is 
