SEC 



.vhich is Grainen creticum fpicatum fecalinum altiflimum, 

 luberofn radice ; Tourn. Cor. 39; and that he himlclf was 

 pofibfled of fpecimens of both. Both were aUo coUetled 

 in the Levant by Tournefort. Desf. Atlant. v. I. 113. 



SECAMONE, an Egyptian name, apparently corrupted 

 by the modern inliabitants of Egypt from tire Greek, crna^- 

 ^ii'.iK ; for Profper Alpinus tells us the plant which bears 

 this name, Periploca Secamone of Linnasus, is elleenied, by 

 that people, a iort of Scammony, and its yellow burning 

 juice is, when dry, reckoned by them a powerful purge, for 

 expelling thin humours. Yet he adds that he knew nothing 

 of their making ufe of the plant in medicine. Such being 

 the origin of this name, we are obhged to protell againll it, 

 as unclaffical. — Brown Tranf. of the Wcrnerian Society, 

 V. I. 55. Prodr. Nov. Holl. v. i. 464. Ait. Hot. Kew. 

 V. 2. 75. — Clafs and order, Pinitandria Digynia. Nat. Ord. 

 Contortic, Liim. Apocine,!., JuU'. Aj'clepiades , Brown. 



Eil. Ch. Corolla wheel-fhapcd. Crown of the Itamens 

 of five leaves. Filaments combined, with external append- 

 ages. Maffes of pollen ereft, attached in four rows to the 

 unfurrowed fummit of the iligma. Follicles with comofe 

 feeds. 



A genus of upright or twining, nearly fmooth (lirubs. 

 Leaves oppofite. Cymes forked, between the footltalks. 

 Floiuers minute. — Mr. Brown declares this genus to be pei'- 

 feftly natural and diftinft, though, from the extreme minutc- 

 nefs of the parts, very difficult to determine. It is the con- 

 nefting link between the true Afckpiadeic and his Periplncea. 

 Five fpecies have been afcertained by the learned author of 

 the genus. 



1. S. egyptiaca. Egyptian Secamone. Ait. n. i. (Seca- 

 mone; Alpin. ./Egypt. 133. t. 134. Periploca Secamone; 

 Linn. Mant. 216. Willd. Sp. PI. v. i. 1249. Thunb. 

 Prodr. 47.) — Stem twining. Leaves eUiptic-oblong, fmooth. 

 Corolla hairy. — Native of Egypt, and the Cape of Good 

 Hope. A green-houfe fhrub, cultivated by Miller before 

 the year 1752, and flowering in July. A Cape fpecimen 

 from Thunberg is in the Linnaan herbarium. The Jlem is 

 woody, twining, with fmooth, round, leafy branches. Leaves 

 about an inch and a half long, on fhortifli (talks, bluntifh, 

 entire, coriaceous, fmooth, with one rib and many parallel 

 tranfverfe veins ; pale, and fomewhat glaucous, beneath. 

 Cymes fliorter than the leaves, repeatedly forked, many- 

 flowered ; their llalks clothed with filky hairs, of a rulty 

 hue ill the dried plant. Flnivers hardly a line in diameter, 

 white. Corolla fmooth at tlie back, its upper furfacc co- 

 vered with (hort denfe hairs. 



2. S. emetica. Emetic Secamone. (Periploca emetica ; 

 Retz. Obf. fafc. 2. 14. Willd. Phytog. fafc. 1.6. t. J. 

 f. 2. Sp. PI. V. I. 1250.) — Stem diffufc. Leaves lanceo- 

 late, fmooth. Corolla fmooth. — Native cf the Ead Indies. 

 Tlie Rev. Dr. Rottler fcnt it from Madras. The roofs arc 

 faid to be ufed inftead of Ipecacuanha. This is a fpreading, 

 fcarecly twining, _/ZirH^, of a more (lender habit than the 

 former, with much narrower leaves. Corymbs axillary, (mall, 

 not a quarter fo long as the leaves, of few Jlotvers, with 

 downy riilly llalks. Our fpecimen is in too early a ftate to 

 difplay the corolla, but Rctzius and Willdonow fay it is 

 fmooth. 



3. S. canefccns. Ploary Secamone. — Stem twining, with 

 downy branches. Leaves ovato-lanccolatc ; downy beneath. 



Corolla downy at the back Sent from the Eall Indies, by 



the late Dr. Roxburgh, in 1789. We prcfume this is what 

 Mr. Brown mentions as his third fpecic?. Our plant has 

 long, twining, round, pale-green branches, finely downy and 

 hoary, in a young (late, like all the Jlalis, the calyx, outfidc 

 of the corolla, and backs of the letrvcs ; which lalt are two 



.S E C 



or three inches long, rounded at the bafe, tapcnng gradu- 

 ally to a bluntilh point. Fleivers numerous, fomewhat 

 umbellate; their common (lalks about equal to the fool- 

 Jlalks. ^ ^ 



4. S. elliptica. Elliptical Upright Secamone. Br. Prodr. 



n. I " Stem ereft. Leaves elliptical, pointed, fmooth. 



General and partial (lower-llalks downy. Corolla naked." 

 — Gathered by Mr. Brown, in the tropical part of New 

 Holland. 



5. S. ovata. Ovate Spreading Secamone. Br. Prodr. 

 n. 2.—" Stem divaricated. Leaves ovate, acute, fmooth. 

 General and partial dower-ftalks nearly fmooth. Corolla 

 naked." — Found by Mr. Brown, in the fame countr>- aii 

 the lalt. 



SECANT, in Geometry, a line that cuts another, or di- 

 vides it into two parts. See Link, &c. 



Thus the hue A M {Plate XIII. Geometry, fg. 4.) is a 

 fecant of the circle A E D, &c. as it cuts the circle in B. 

 It is demonftrated by geometers : i. That if fevcral fecants, 

 MA, M N, M E, &c. be drawn from the fame point M, 

 that pairing througli the centre, MA, is the greatelt ; and 

 the reft are all fo much the lets, as they are more remote 

 from the centre. On the contrary, the portions of them 

 without the circle M D, M O, M B, are fo much the 

 greater, as they are farther from the centre. The lead is 

 that of M A, which pades through the centre. 



2. That if two fecants, M A and M E, be drawn from 

 the fame point M, the fecant M A will be to M E as M D 

 to MB: or ME X MD = MA x MB = the fquare 

 of a tangent to the circle drawn from the point of con- 

 currence M. 



Secant, in Trigonometry, denotes a right line drawn from 

 the centre of a circle, which, cutting tlie circumference, 

 proceeds till it meets with the tangent to the fame circle. 

 Thus the line F C {Plate Trigonometry, Jig. 4.) drawn from 

 the centre C, till it meets the tangent E F, is called a fe- 

 cant ; and particularly, the fecant of the arc A E, to which 

 E F is tangent. 



The fecant of the arc A H, which is the complement of 

 the former arc to a quadrant, is called the co-fecani, or fetctnl 

 of the complement. 



The fine of an arc, A D, being given, to find the fecant 

 of It, F C, the rule is, as the co-fine D C is to the ivholi- 

 fine, fo is the whole fine, or radius, A C, to the fecant C F: 

 or the fecant is a third i)roportional to the co-fine and radius. 

 See Sine. 



To find the logarithm of the fecant of any arc, the fine 

 of the complement of the arc being given, multiply the lo- 

 garithm of the whole fine by two, and from the product lub- 

 traft the logarithm of the fine complement ; the rem.iinder 

 is the logarithm of the fecant. The rcafon of whicli opera- 

 tion is obvious ; bccaufc ----- = to C F ; and, therefore, 



from the nature of logarithms, twice the log. of E C — 

 the log. of D C = the log. of C F. 



Secants, Line of. See Skctoii. 



SECAS, in Geography, a chiller of fmall iflands in the 

 Pacific ocean, near' the coad of Veragu.i. N. lat. 8'^ 20'. 

 W. long. 83° 16'. 



SECATABBAS, a town of Afiatic Turkey, in the 

 province of Diarbekir ; 75 miles S.W. of M^fnl. 



SECCA, a fmall id.nid near the coad of Idria. N. hit. 



N. 



44" 52'. E. long. 14' j'. 



SECCHE, a fmall idand near the cond of Idna. 

 lat. 45" 14'. E. long. 1 V'40'. 



SECCHIA, a river of Italy, which runs into the Po, 

 3 miles N. of Quidelli', in the duchy of M.mtua. 

 ^ ^ SECEDERS, 



