MifceManea Curiofa. iji 



An ExtraB of a Letter from the 

 Reverend 2)r. John Wallis, to 

 Richard Waller, Efy; Secretary 

 to the Royal Society^ concerning 

 the Sfaces in the Cycloid, which 

 are perfectly Quadrable. 



Oxford, Augufi 22. 1695, 



5 / R, 



IT Find it is thought by moft, that there is 

 j[_ no other part of the SemicycLoid Figure 

 ( adjacent to the Curve ) that is capable of 

 being Geometrically Squared, but thefe two^ 

 viz. 



1. The Segment AbV, (Fig, 28 J taking 

 AV -=z \ A &, (which was firft obferv'd by 

 Sir Clmftofher Wren^ and after him by Huge- 

 nim and others) and it is ~ 3 % s Rz=z \ R z 



2. The Trilinear A d B (taking d D, in 

 the Parallel d B C, paffing through the Cen- 

 ter C,j which is R 2 . 



r But it is otherwife (as I have fhewed in 

 my Treatife, Be Cycloide^ and that, Be Mom * 

 the Figures of which latter I retain here, 

 fo far as they concern this Occafion j) there 



being 



