Page:Cyclopaedia, Chambers - Volume 2.djvu/783

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for the Theory andEffetl of Steering ; fee Sailing,

STEGANO&RAPHY 5 the Art of fecret Writing ; or of writing in Cyphers, known only to the Perfons correfponding. See Cypher.

One JEneasTa&icus, Two thoufand Years ago, as we are told by 'Pclybius, had invented 20 different Manners of writing fo as no Body but thofe let into the Secret, could understand any thing of the Matter. '

But now-a-days, hardly any thing can be written by this Art, but what may be Decyphered, and the Meaning dif- covered. And to this Art of Decyphering, that excellent Mathematician, Dr. Wdlis, hath contributed much.

STEGNOSIS, from riya, conppo, I fix, or harden) is an Obftrucfion of the Pores ; whence Stegnoticks are the fame as Aflringents. See Astringent.

STEGNOTICKS, in Medicine, Remedies proper toclofe and ftop the Orifices of the Veflels, when ftretch'd, lacerated, &c. SeeSTYPTicE.

Such are Pomgranate Leaves, red Rofes, Plantain Leaves, Tormentil Root, &c.

Stegaoticks are proper in the Hemorrhoids, and other Fluxes of Blood.

The Word is form'd from the Greek riyu, impedro, con- ftipio, I hinder, clofe.

STELLATE 'Plants, fuch as have their Leaves growing on the Stalks, at certain Diftances, in the Form of a Star with Beams 5 or fuch Flowers as are Star-like orfullof Eyes, refembling Stars, in the Thrum or Pendants. SeePr,ANT.

Mr. Ray makes this the Tenth Genus of Etiglifi 'Plants ; of this Kind is Crofs-Wort, Moll-ugo, wild Madder, Afperula, or Woodruff, Gallium or Ladies Bed-ftraw, Aparine or Cleavers, Rubia Tinftorum or Dyers Madder.

To which he adds, as akin to this Genus, the Nafturtium Indicum, Indian CrefTe, or yellow Lark-Spur.

STELLIONATE, STELLIONATUS, in the Civil Law, a kind of Crime committed by a fraudulent Bargain, where one of the Parties fells a thing for what it is not.

As if I fell an Eftate for my own, which belongs to an- other ; or convey a thing as free and pure, which is already engaged to another; or put off Copper for Gold, &c.

Oijas fays, the Word comes from Stellio, a very fubtile kind of Lizzard. We find mention hereof in the Code Jib. 9. Tit. 34.

The Romans frequently ufed Stellionatus to exprefs all Kinds of Crimes that had no proper Names.

STEM, in Botany, that Part of a Plant arifing out of the Root, and which fuftains the Leaves, Flowers and Fruits. See Plant.

In Trees, the Stem is called the Think or Stock ; in Latin, Catidex and Truncus. See Stock, &c.

In Herbs, 'tis ordinarily call'd the Stalk ; by the Latins, Catllis and Scopus, when (freight like a Column.

When flender, and creeping on the Ground, as that of Nummulary, fome Authors call it Viticltlus.

In the fevcral Kinds of Corn and Plants of that Kind, 'tis call'd Culrmis.

The Stem of the Plant, according to Dr. Grew, is no more than the Cutis or Skin which at firft covers the two Lobes, and the Plume of the Seed, and which is further dilated as the Plant grows. See Flume, Seed, %£c.

Stem of a Ship, is thar main Piece of Timber which comes bending from the Keel below where it is Scarfed as they call it ; that is pieced in, right before the Fore-caftle. This Stem it is, that guides the Rake of the Ship, and all the Butt-ends of the Planks forwards, are fixed into it. This in the Secfion of a Firft Rate Ship, is called the Main Stem.

STENTOROPHONIC Tube, zfpeaking Trumpet ; thus call'd from Stentor, (a Perfon mentioned in the Fifth Book of the Iliad, who could call louder than Fifty Men) and ipuvti, Voice.

The Stentcrophonic Horn of Alexander the Great is fa- mous ; with this he could give Orders to his Army at the Diftance of 100 Stadia ; which is above 12 Englifi Miles. See Spearing Trumpet.

STEP. See Pace and Stair,

Step and Leap, in the Manage, one of the Seven Airs or artificial Motions of a Horfe ; confiff ing, as it were, of three Airs ; viz. the Pace or Step which is terra a terra ; the railing a Curvet ; and the whole finifhedwith a. Salt or Leap.

The Step, properly, puts a Horfe on the Hand, and gives him a Rife to Leap ; like one that runs e'er he leaps, that -he may go the higher.

For Leaps of all kinds, the Rider is not to give any Aids or Helps with his Legs ; only to hold him well up with the Bridle-hand when he rifes before, that he may rile the higher behind : when he begins to rife behind, he is to put the Bridle-hand a little forwards to hold him before, and ftay him there on the Hand, as if he hung in the Air ; timing the Motion of the Bridle-hand fo, as to take him like a Ball on the bound ; which is the great Secret in Leaping.

STERCORARIANS,orSTERCORANISTS,aName thofe of the Romifj Church have anciently given to fuch as held that the Eucharift was liable to Digeftion, and all its Confeijucuces, like other Foods, See Sacrament.

The Word is form'd from the Latin, Sterctts, Dung'. Card. Humber in his AnfwcrtoJta <Pefforat, treats him as a. Stercoranifl, merely for holding, that the Eucharift breaks the Faft ; which Opinion he imagined led directly into Ster- coramfm.

STEREOBATA, in the ancient Architeaure, the Eafis or Foundation whereon a Wall or other Building is rais'd. See Base.

This anfwers pretty well to the continued Socle or Bafe- ment of the Moderns : Some confound it with the ancient Stylobata, or Pedeflal ; but in efteft, the Stereobata is that to the Stylobata, which the Stylobata is to the Spin or Bale. See Stylobata.

The Word is form'd from the Greek, rsssofartf, folid Prop.

STEREOGRAPHIC TrojeSion of the Sphere, is that wherein the Eye is fuppofed to be placed, in the Surface of the Sphere. See Projection of the Sphere.

The Method and Practice of this Projeif ion, in all the principal Cafes, viz. on the Planes of the Meridian, Equi- noctial and Horizon, is as follows 5

i° Stereographic 'ProjeSion on the Ttane of the Meridian*

LetZQJNE (Fig. 5 3.) be the Meridian, Z and N the Poles, as alfo the Zenith and Nadir ; E Q_ the Equinoflial and Horizon; Z N the equinoffial Colure, and prime vertical Circle : Z 15 N, Z 30 N, Z 45 N, (£c. are Hour-circles or Meridians, and alfo Azimuths, becaufe the Pole is in the Zenith ; and to defcribe thefe Circles, find the Points, 15, 30, 4J, 60, iSc. in the Equinoctial, by fetting the Half- tangent of their Diftance from T ; and then their Centres are found by fetting their Co-fecants, both ways, from their Points of Interfecf ion with the Equator ; S, S, and v?, vr, are the Northern and Southern Tropics, which are defcribed by fetting the Half-tangent of 23 Degrees 30 Minutes from V each Way ; then the Tangent of its Complement, viz. 66 Degrees 30 Minutes, each way from thence on the Colure produced, gives their Centres ; by this Method, all Parallels of Declinations may be drawn. Or you might have fet the Co-fecant of the Parallel from the Centre of the Primitive, which would alfo have found the fame Point for the Centre of the Parallel, whofe Radius is equal to the Tangent of its Diftance from its Pole. Thefe Parallels in this Projcflion, are alfo Almicanters, or Parallels of Altitude ; s, v? is the Ecliptick, which muft be divided from the Divifion on the Scale of Half-tangents ; but denominated according to the Signs of the Zodiac, reckoning 30 Degrees to each Sign.

2° Stereographic T'rojetlion on the 'Plane of the Equinoffial.

Let S C (Fig. 24.) be the Meridian, and folftifial Colure 5 E N the equinoctial Colure, and Hour-circle of 6 ; V the North Pole ; ffi s, the Northern Tropick ; E S N the Northern Half of the Ecliptick (whofc Centre is found, by fetting off the Secant of 23 Degrees 30 Minutes from s) and its Pole is at a the Interfeaion of the Polar Circle and Meri- dian, being the Place through which all Circles of Longi- tude muftpafs; and E Z N the Horizon of London, which is defcribed thus : Set the Half-tangent of the Co-latitude, from P to Z ; then the Tangent of the fame, fet from P to O, or its Secant from Z to O, gives its Centre ; and its Pole will be at h 38 Degrees 30 Minutes, (in the Half-tangents) diftant from F, where h is at the Zenith. To draw any other Circles in this Projeaion; 1. For Circles of Longitude, which muft all pafs through a, and the feveral Degrees' of the Ecliptick ; fet the Tangent of 66 Degrees, 30 Minutes, from a downwards, on the Meridian produced ; which will find a Point, through which a Perpendicular, drawn to the Meri- dian, fhall contain in.it the Centres of all the Circles of Longitude, whofe Diftances fet oft" to the Radius P x, fhall be the Tangents of the Degrees of their Diftances from the Meridian, S P C (which is that belonging to 180 Degrees. 2. All Parallels of Declination are drawn by fetting the Half-tangents of their Diftances from P. 3. All Azimuths, or Vertical Circles muft pafs through h d, the Zenith : Since, therefore, the Zenith is 38 Degrees 30 Minutes diftant from P, fet the Co-fccant of that (or the Secant of $1 Degrees 30 Minutes) from h on the Meridian extended below, and that fhall find the Point x, the Centre of the Azimuth of Eaft and Weft, viz. E h N ; and the Centres of all the reft are in a Line that is perpendicular to the Meridian, and drawn through x. 4. Circles of Altitude or Almicanters, are leffer Circles, whofe Poles are not in the Plane of the Projection ; thus the Circle O e, is a Parallel of Altitude 5° Degrees above the Horizon, y. All Hour-circles are ftrait Lines from the Centre to the Limb.

3 9 Stereographick Trojetlion on the Tlane of the Horizon.

Firft draw a Circle reprefenting the Horizon, and quarter it with two Diameters ; then will » be the Zenith of the Place,

12 z 12