Page:Cyclopaedia, Chambers - Volume 2.djvu/705

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SELL,, in Building, is ofTwafcinds^ viz. Ground^ Sell, which is the loweft Piece of Timber in a Timber Building, and that whereoti die whole Superitructure is raited ;, and- Window-Sell, called: alio ■ Wtn.iow-Sod, the. bottom Piece- ina Window-Frame. See Window.

SEM-BIANS, a Sect of ancient Hereticks, denominated; from their Leader, Sembius or Sembianus, who condemned ail Ufe of Wine, as Evil of irfelf ;_ perfuaded. his Fol- lowers, that the Vine was a Production of Satan and: the Earth 3 denied the Refurrection of the Dead,.and rejected moft of the Books of the Old Teftament. J<weO.

SEMBRADOR,. an Engine, invented by Don Jof. de £.zicatettc, for the evenly Sowing of Seeds ; defcribed in the Whitofophical TranfaBions, under the Title of the Sfanift Sembmaor. The Perfection of Agriculture is. al- lowed to confilt in fewing the Plants, in proportionable Spaces, and givingiufficicnrDeprh to the Roots, that they may fipread, and receive their neceffary Nourilhment : yet' is very, little Care taken in the Practice of this im- portant Part of Husbandry 5 but all forts of Grains fewn 6y Handfuls, .catt at Random ; by which means Four Parts •inTive of the Seed are loft. To remedy this Inconye- ffeace, the Sembrador or Sower, is invented, which being feftenecl to the Plough, the whole Buiinels- of Plowing, Sowing and Harrowing is done at once, the Seeds- man's Trouble fave.d, and the Grain fpread at equal Diftances, and equally deep at the bottom of che Furrow. An Ex- periment hereof was made before the Emperor Leopold in the Fields of Luxemburg in Aufiria, where the Land tifoally yields four or five fold; but the Crop from the Gfound (owed by this Jn.ftru.ment, was Sixty fold, as appears" by a Certificate of the Emperor's Officer, appointed to' fee the Experiment : Si'gn'd Vienna* Ai/guji J. 1663. A Figu-re of" the Sembrador, we have in the TranfaBions, by the 1 Earl of Czfkmain,

SEMEIOSIS, in Medicine. See Diagnosis.

SEMEIOTJCA, that Part of Medicine, which confiders the Signs or Indications of Health avid Diieaies ; and en- ables the Phvfician to judge what is, was, or will be the State, Degree, Order and Effect of Health or Sieknefs. See SiGtf and Indication" ; fee alfb Medicine. The Woi'd is form'd from rhe Greek "Zip-wrim, of Ss/whw,

"SEMENTINiE FERIJE, in Antiquity, Feafts held annually among the Romans^ to obtain of the Gods a plentiful Harvefr. They were held in the Temple of 'Ter- ra or the Earth; where folemn Sacrifices were offered to* Terra and Ceres. The Time of the Celebration was about Seed- Time, ufually in the Month of January 5 for Macrobitts obferves, they were moveable Feafts, They had their Name from Semen, Seed.

SEMETS, in Botany ; Dr. Grew ufes the Word for the Apices of the Attire of Plants. See Apices.

SEMI, a Word borrow'd from the Latin, fignifying Jfalfi but only ufed in Compufition with other Words,^ as in the following Examples. The French, inftead of Sem'fi frequently ufe 1)emi,

In Mufic, Semi has three' federal Ufages : Firrt-, when added to a Note, it exprefles a Diminution of Half its "Value, as Semi-lreve, &c. which See. Secondly, when added to the Name of an Interval, it expreffes a Diminu- tion, not of Half, but of a minor Half-tone, or four Commas in the whole Compafs. Thirdly, it fbmetimes iignifies an Imperfection. Thus Scmicircolo or Circolo- mez-z-o, Iignifies an imperfect Circle, which is the Mark of imperfect Time, that is, of double Time ; whereas, the Circle, being a Character of Perfection, marks triple

Time.

SEMINARIANS, a Branch of the Ancient Arians^ confining of fuch a?, in Appearance, condemned the Errors of that Hereliarch, but yet acquiefced in the Principles thereof; only palliating and hiding them under fbfter, and more moderate Terms. 'Tis true, they ieparated from the Avian Faction ; but yet could never be brought to acknowledge, that the Son was Homootfios, that is, confubftantial, or of the fame Subftance with the Father. They would only allow him to be Homoionjios, that is, of a Subllance like the Father. Though, as to E'xprefiton, they only differ d from the Orthodox by a fingle Letter ; yet were they, in Effect, in the Error of the Ariani ; as they placed the Son in the Rank of Creatures. It did not avail the teaching, that there was no other Creature of the fame Clafs with him ; fince by denying him confubftantial with God,they effectually precluded him from being truly God. Yetfbme, even among the Orthodox, ufe the Word U&mhnfioi, in fpeaking of the Son ; applying fuch an Idea to it, as,it fcems, is confiftent with Orthodoxy. See Arians,

SEMI-BREVE, is Mufic, a Note, or Meafure of Time, comprehending the Space of Two Minims, or Four Crotchets, or Half a Sreve. The Semi-breve is ac- counted one Meafure or Tim* ; ©r the Integer, in Fractions

and Multiples whereof the- Time of the other Notes is ex-preffed. Thus the Minim is exprefs'd'by * ; a Crotchet ky j, &c: r. e. by | of a Meafure or Semi-breve. A linve by 1 ; a Long by 4, that is, by, 4,, Meafur.es. or Semi breves. The Character of the Semi-breve is O.

Semi-Circle, in Geometry, a Figure comprehended between the Diameter of a Circle.,, and Half the- Circum- ference. See Circle-. Two Semi-Circles can only cut each other in one. Point.

Semi- Circle r istdio an Inftrum.ent.in Surveying, catt'&alfo. Graphometer. It con fill's of a Semi-circular Limb, as F I_G (Tab. Surveying Fig. 16. ) divided into 180 Degress and fbmetimes lubdivided. Diagonally or otherwife, into Mi- nutes, This Limb is fubtended by a Diameter F G, at the Extremities whereof are Erected two Sights. lathe. Centre, of the Semi-circle, or rhe Middle, of the Diameter,, is fix'd a Box and Needle. On the fame Centre is fitted. an AU* dade or- moveable Index, carrying two other Sights,, as H I. The whole is mounted on a Staff with a Ball and Socket,

In Effect,, the Semi-arcla is. nothing elfe. hut Half a. Theodclite ; with this only Difference, that whereas the Limb of the Theodolite, being an intire Circle, takes in all the 360 fucceffively ; in the Semi circle, the Degrees only going from 1 to 180, 'tis ufiial to have the remaining 180°, or rhofe from 18.0° to 360, graduated in anatker Line on the Limb, within the former.

To take an Angh T:ith aSimi- Circle.

Place the Inftrument in filch Manner, as that the Radius C G may hang over one Leg of the Angle, to be meafuj'd, and the Centre C over the Vertex of the fame. The firft is done by looking through the Sights F and G at the Extremities of the Diameter, to a Mark fixed up in one Extremity of the Leg : The latter is had by letting fall a Plummet from the Centre of the Inltrument. This done, turn the moveable Index H I on its Centre towards the other Leg of the Semi-circle, till through the Sights fixed on it, you fee a Mark in the Extremity of the Leg. Then, the Degree which the Index cuts on the Limb, is the Quantity of the Angle.

For further Ufes of the Semi-circle, they are the fame with thofe of the Theodolite. See Theodolite.

Semi-Cupitjm, a HalfBath, wherein the Patient is only up to the Navel. See Bath.

Semi Diameter, aRight Line drawn from the Centre of a Circle or Sphere, to its Circumference ; the fame with what we otherwife call Radius. See Raeivs. The Diftances, Diameters, &c. of the Heavenly Bodies, are ufually estimated by Aftronomers in Semi diameters of out Earth. See Earth; SeealfoSuN, Planet, £Sc.

To find the Semi-diameters of the Primary Planets m Semi-diameters of the Earth.

Since the Sun's true Semi-diameter is 152 Semi-diameters of the Earth 5 and we have the Ratio of the ^Diameters of the Primary Planets to that of the Sun (See Dia- meter ; their Semi diameters are eafily found by the Rule of Three : Thus, the Semi-diameter of Saturn will be found 20 j ° ; that of his Ring 45 ^ ; that of Jupiter 27tt5 tnat °* Ma-rs^'j that of Venus *$ and that of Mercury '„», See Planet.

Semi-Colon, in Grammar, one of the Points of Stops, ufed to diftinguifh the feveral Members of Sentences from each other. See Sentence and Point. The Mark or Character of the Semi-colon is (■;) It has its Name, as having a fomewhat lefs Effect than a Colon, or as de- manding a fhorter Paufe. The Ufe of the Semi-colon, the Grammarians generally fay, is, To mark a Senfe lefs compleat than the Colon, and more compleat than the Comma; but this only conveys a very obfeure Idea. In effect, the prccife Ufe of the Semi-colon^ or what it is diltinguifhes it from the Colon, is a Thing very little known in the World. Our belt Authors feem to ufe them promifcuoufly. See Colon.

Mr. Ward, we believe, is the firft (and he in the pre- fent Year 1734) who ever fettled the precife Ufe of the Semi-colon. His Obfervation is, That the Semi-colon is properly vfed to diflwguife the conjunct Members of Sen* fences ; Now, by a confanB Member of a Sentence, he means, fuch a one as contains at leaft two fimple Members. See Sentence. Whenever, then, a Sentence can be divided into leveral Members of the fame Degree ; which are again divifible into other fimple Members, the former are to be feparated by a Semi-colon* For an Inflance : It Fortune bear a great Sway over him, who has nicely ftated and concerted every Circumftance of an Affair; we muft not commit every Thing, without Referve to Fortune, left flie have too great a hold of us. Again, Si quantum in figtv Ucifqm defertis audacia pQtefi> tantum in Foro atque

Judiciis