CON 



CON 



" The nuptials he disclaims, 1 urge no 



more ; 

 Let him pursue the promised Latian 



shore. 



A short delay is all I ask him now ; 

 A pause from grief, an interval from 



woe." 



CONCHIUM, in botany, a genus of 

 the Tetrandria Monogynia clasg and or- 

 der. Calyx none ; petals four, support- 

 ing the stamina ; stigma turbinate, mu- 

 cronate ; capsule one celled, two-seeded ; 

 seeds winged. 



CONCINNOUS, in music, a term ge- 

 nerally confined to performance in con- 

 cert. It applies to that nice discriminat- 

 ing execution, in which the band not on- 

 ly gives with mechanical exactness every 

 passage of the composition, but enters 

 into the design or sentiment of the com- 

 poser, and, preserving a perfect concord 

 and unison of effect, moves as if one soul 

 inspired the whole orchestra. 



CONCHOID, in geometry, the name 

 of a curve, given it by its inventor, Ni- 

 comedes, and is thus generated. 



Draw the right line QQ (see Plate III. 

 Miscel. fig. 14.) and AC perpendicular to 

 it in the point E ; and from the point C 



draw many right lines CM, cutting the 

 right line QQ in Q ; and make QM=QN, 

 AE=EF, viz. equal to an invariable line : 

 then the curve, wherein are the points 

 M, is called- the first conchoid ; and the 

 other wherein are the points N, the se- 

 cond ; the right line QQ being the direc- 

 trix, and the point C the pole : and from 

 hence it will be very easy to make an in- 

 strument to describe the conchoid. 



The line QQ is an asymptote to both 

 the curves, which have points of contra- 

 ry flection. See ASYMPTOTE. If QM= 

 AE=a, EC=6, MR=EP=x, ER= 

 PM=# . then will a- 6* 2 a 1 b x-\-a- x* 

 =6* x* 2 b a?3+a*-Hff* y>, and express 

 the nature of the second conchoid ; and 

 a:*-f 2 b xl+y> ^-f 6 1 a- i =a i b>+2 & b x 

 -f-a 1 x-, the nature of the first; and so 

 both these curves are of the same kind. 



This curve was used by Archimedes 

 and other ancients in the construction of 

 solid problems ; and Sir Isaac Newton 

 says, that he himself prefers it before 

 other curves, or even the conic sections, 

 in the construction of cubic and biqua- 

 dratic equations, on account of its sim- 

 plicity and easy description, shewing 

 therein the manner of their construction 

 by help of it. 



END OF VOL. HI. 



