Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/899

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PADDLE, or Paddle-/^, a fmall ftafF, ihod with 1 iron, for cleanfing the plough from ftubble, clods, earth &C Dia. Ruft. in voc.

It is alfo much ufed by mole-catchers. PADUS, in the Linnsan fyftem of botany, the name of a ge- nus of plants, the characters of which are thefe : The cup is a permanent perianthium, formed of a fmgle leaf, of a cam- panulated figure, villofe at the bafe, divided into five fer- ments, patent, and fcarce at all reflex ; the flower confifts of five large, roundiih, patent petals, inferted by their ungues into the edge of the calyx ; the ftamina are twenty or thirty filaments, of a fubulated figure, nearly of the length of the flower, and inferted into the calyx ; the antherae are round ifh j the germen is roundifh ; the ftyle is filiform, and of the length of the ftamina ; the ftigma is obtufe and entire ; the fruit is a roundiih drupe j the feed is an ova), acuminated nut, with a furrow ; the receptacle of the flower, which in vefts the inner furface of the cup, is hairy in this genus which comprehends the Laurocerafus, and Cerafus avium of authors. Vid, LinntsiGen. Plant, p. 215. PAIGLES, a name fometimes uf'ed for the Primula, or Cowjlip.

See the article Primula, Suppl. PAINS, or After-PAivss in Midwifry. See the articles Deli- very and Lying- in~women. VALM-tree, Palma, in botany, the name of a diftincT: genus of plants, called by Linnseus Phcenix. See the article Phoe- nix, Suppl. PALMA Chrijli, a name frequently given to the common Ri-

dnus. See the article RIcinus, Suppl. PALMETTO, the name by which fome call a fpecies of the palm or date-tree, defcribed by Linnaeus under that of Phce- nix. See the article Phoenix, Suppl. PANAX, in the Linnjean fyftem of botany, the name of a di- ftinct genus of plants, the characters of which are thefe : The umbel of the calyx is fimple, equal and thick ; the involu- crum is very filial], and formed of a number of leaves, fubu- ulated and permanent ; the perianthium of each flower is very fmall, divided into five fegments, and permanent ; the general corolla is uniform, and the peculiar ones confift of live oblong, crooked, equal petals. The ftamina are five very ftiort filaments j the anthera are fimple ; the germen of the piltil is roundifh, and placed below the perianthium ; the ftyles are two, and fmall ; and the ftigmata are fimple ; the fruit is a roundifh berry, having one cell, and is coronated with the cup ; the feeds are two, and of a kidney-like ihape.

This genus comprehends the famous Ginfeng, Araliajlrwn, Ninfi, and Aureliana of other writers. PANCRATIUM, the fea-daffodil, in botany, the name of a genus of plants, the characters of which are thefe : The cup is an oblong, obtufe, comprefled fpatha, opening in the plane fide, and deciduous ; the ne&arium of the flower is formed of a Angle leaf, of a cylindraceo-infundibuliform lhape, co- loured at top, and with an open mouth, divided into ten legments ; the petals are fix, lanceolated and plane, and are inferted externally into the tube of the nectarium, above the bafe ; the ftamina are fix fubulated filaments, af- fixed to the apex of the nedtarium ; the antherae are oblong, and incumbent ; the germen of the piftil is trigonal, and pla- ced under the receptacle ; the ityle is filiform, and fomewhat longer than the ftamina ; the ftigma is obtufe ; the fruit is a roundifh, triquetrous capfule, formed of three valves, and containing three cells j the feeds are numerous and globofe ; and the receptacle is columnar. Vid. Lintuei Gen. Plant.

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PANIC, Pan'tcum, in botany, the name of a diftincT: genus of plants. See the article Pan 1 cum, Suppl.

PANICLE, Panicula, among botanifts. See the article Pa- nicula, Cycl. and append.

PANICULA (Cycl.) — According to Mr. Miller, the Panicula, or panicle, is a ftalk diffufed into feveral pedicles, or foot- ftalks, fuftaitilng the flowers or fruits, as in oats, &c. Mil- ler, Gard.Dia.

PANORPA, the fcorpion-fly, in zoology, a genus of four- winged- infeffe of the Neuropetra kind, the diftinguifhing chara&ers of which are thefe : Its.roftrum or trunk is of a cylindric figure, and horny ftru&ure ; and its tail is furnifhed with a weapon of the cheliform kind. See the article SCOR- PION;/?^, Suppl.

PANSEY, or Pansy, a fpecies of violet, otherwife called the Heart' s-ectfe. Seethe articles Viola, Suppl. and Heart's ease, append.

PAPAW, the name by which fome call the Papaya, a diftinct genus of plants. Seethe article Papaya, Suppl.

PAPPOSE •plants i among boianifts, fuch whofe feeds are co-

pad atjStV f tf #, w »«down. See the article Pappus, Cych

PARABOLA (Cycl.)- 0>W 7 -P A r AB ola, in geometry is ufed particularly for that Parabola which' not only ofculates or meafures the curvature of any curve at a given point, but alio meafures the variation of the curvature at that point bee Mac Ltmrtn's Appendix to his Algebra, p. 17. Cramer Analyf. desLignes Courbes, p. 559. See the ai tide Curva- ture, Append.

A curve, ftriclly fpeaking, may have an indefinite number of Ujculatory Parabola! at any of its points ; but the appellation may be reftrained to that particular Parabola which meets the curve fo clofely, that no other parabolic arc can be drawn between them j and this Parabola will meafure the variation or the curvature of the curve at that point. See the article variation of curvature, Suppl.

PARABOLIFORM Curves, a name fometimes <nven to the parabolas of the higher kind

PARADISE (Cycl.) Bird ./Paradise. See the articles Pa-

RADISiA andMAKOCODIATA, Suppl

PARALLELOGRAM (Cycl. and Suppl.) _ Newtonian, or Analytic. PARALLELOGRAM,in algebra, an appellation ufed for an invention of Sir Ifaac Newton's, to find the firft term of an infinite converging feries.

This is fometimes called the method of the Parallelogram and Ruler ; becaufe a ruler or right line is alfo ufed in it. This analytic Prallelogram is formed by dividing any Paralle- logram into equal fquares or Parallelograms, by' lines drawn horizontally and perpendicularly through the equal divifions of the fides of the Parallelogram. The cells thus formed are filled with the dimenfions of the fpecies x and_y, and their products. The powers, y° = 1, y, ja, y 3, y t 9 & c. of y, for inftance, being placed in the loweft horizontal range of cells, and the powers of x, or x° = 1, x, x% xl, he. in the vertical co- lumn to the left, or vice verfa i fo that thefe powers and their products will ftand thus :

B

Then, when any literal equation is propofed, mark fuch of the the Parallelograms or cells, as correfpond to all its terms ; and let a ruler be applied to two, or perhaps more, of the Pa- rallelograms fo marked, of which let one be the loweft in the left-hand column at A B, the other touchina; the ruler to- wards the right-hand ; and let all the reft not touch ino- the ruler He above it. Then felect: thefe terms of the equation which are reprefented by the Parallelograms that touch the ruler, and from them find the quantity to be put in the quote. This is Sir Ifaac Newton's famous rule, of the application of which he has lelt us fome examples in his method of flux- ions and infinite feries, p. 9 and 10. but without demonftra- tion ; which has been fince fupplied by others. See Mr. Colfon's Comment on that treatife, p. 192, feq. Mac Lau- rin's Algebra, p. 251, feq. and particularly Monf. Cramer's Analyf. des Lignes Courbes, chap. 7. p. 148, feq. This learned author obferves a, that this invention, which is the true foundation of the method of feries, was but imperfect- ly underftood, and not valued as It deferved for a long time. He thinks it more convenient in practice to ufe the Analytic Triangle b of the Abbe de Gua, which takes in no more than the diagonal cells lying between A and C, and thofe which lie between them and B. [* In his preface, p, n. b Lib. cit. p. 156.]

PARALLELOPLEURON, a term ufed by fome writers for an imperfect: parallelogram, or a kind of trapezium, having unequal angles and fides ? but which obferve a certain regula- rity and proportion.

PARAMECIUM, in zoology, the name given by Dr. Hill to a genus of animalcules of the Gymnia kind, and of an irre- gular oblong figure.. See the articles Animalcule Cych Suppl. and Append, and Gymnia, Append. Of this genus authors defcribe feveral fpecies ; for which fee Hill, Hift. Anim. p. 4. feq.

PARASITICAL Plants. See the article Parasite, Cycl

PARK Leaves, a name by which the Androftsmum, or Tut/an; is fometimes called. See the article Androsj^mum, Suppl.

PARENCHYMAL/. ;^-Befides the veffels and canals of the human body, the antients fuppoied a fimple homogeneous and firm matter, peculiar to each part;, and thereby diftinguifhing

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