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A Description of the Admirable Table of Logarithms

(Page 3)

 

  Therefore in what proportion QS is cut in R, in the same proportion (by the 10 of the 6 of Euclide) Let aZ be cut in c. and so let b running from a to c in the first moment, cut off ac from aZ, the line or sine cZ remaining.
And from this cZ let b proceeding in the second moment, cut off the like segment, or part, as QR to QS: and let that bee cd, leauing the sine. dZ. From which therefore in the third moment, let b in like manner, cut off the segment de, the sine eZ being left behinde. From which likewise in the fourth moment, by the motion of b, let the segment cf be cut off, leauing the sine fZ. From this fZ in the fifth moment, let b in the same proportion cut off the segment fg, leauing the sine gZ, and so forth infinitly. I say therfore out of the former definition, that here the line of the whole sine aZ, doth proportially decrease into the signe gZ, or into any other last sine, in which b stayeth, and so in others.
 
A Corollary Hence it followeth that by this decrease in equall moments (or times) there must needes also bee left proportionall lines of the same proportion.
For what continuall proportion there is before of the sines to be diminished, aZ, cZ, dZ, eZ, fZ, gZ, hZ, iZ, and kZ, &c. and of the segments cut off from them ac, cd, de, ef, fg, gh, hi, and ik, there must needes be also the same proportion of the sines remaining, that is, cz, dz, ez, fz, gz, hz, iz, and kz, as may manifestly appeare by the 19 Prop. 5 and 11. Prop. 7, Euclid.
 

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Last modified: October 07, 2002