Page:Cyclopaedia, Chambers - Volume 2.djvu/738

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S I'R

Wownifli Red, fuch as that of our Ruddle. Simple figni- fie* Love, Youth, Beauiy, Rejoicing and Liberty ; whence it is, that Letters of Grace, Abolition, Legitimation, $c. areufed to be feal'd with Green Wax. See Green. F. Menejlrier de- rives it from the Greek, Prafina hopla, Green Armories ; by corruptedly retrenching the firft. Syllable, pr&j which is no new Thing among Oriental Words, witnefs Salonica for Theffalonica.

SINUOSITY, a Scries of Bends and Turns in Arches, or other irregular Figures j fometimes jetting out, and fbme- times falling in. Such is the Motion of a Serpent, &c. 'Tis she Sinuofity of the Sea Coafts that forms Bays, Ports, Capes, £S?f. Du Loir obferves, that the Courfe of the River Mean- der, creeping in a thoufand agreeable Siniiofifies, ferved Deda- fatS&s a Model to form his Labyrinth by. See Labyrinth.

SINUS, in Chirurgery, a little Bag or Sacculus, form'd by the Side of a Wound* or Ulcer ; wherein Pus is col- lected. See Pus.

Sinus's that flope downwards, Scultet obferves, are diffi- cult to heal ; Yet that Surgeon undertakes to cure any Sinus in a Week, by the Medicaments- he defcribes Page 338, and an agglutinative Bandage. He adds, that he never comes to make an Incifion, till he finds that the Pharma- ceutic Applications are ineffectual 5 and that for the Dilata- tion of Sinus's, he does not ufe the deceitful Scalpel 5 as being more apt to deceive the Operator than the Patient.

Sinus, in Anatomy, a kind of Cavity in certain Bonss, and other Parts, the Entrance whereof is very narrow, and the bottom wider and more f'pacious. See Bone. Of thefe Sinus's, we find fe veral in the fe veral Parts of the Body; particularly in the Bafis of the Skull, on the Offa petrofa,. where the An- cients imagined their Ufe was to render the Bones more light; In fe veral of the Joints of the Body, they ferve to receive the Apophyfes of the other Bones, In the Duplica- tures of the U)ura Mater, are fe veral J/tzW-J's, which Doctor {Drake obferves to be venous Channels, form'd for the Re- conveyance of the Blood. Of thefe, Four only are confider- able, viz. the Skim Lmgitudmalis,. which running along the middle of the convex Part of the Brain, fends out a Branch en each Side, between the Brain and Cerebellum, call'd the Lateral Sinus '& : Andihelbrcular Herophili, form'd out of a Concourfe of the Lateral SinUS\ and Pineal Gland. They are all form'd of the feveral Venous Branches, which return the Blood from the Brain and Cerebellum, and deli- ver their Contents info the Jugular Veins 5 whereof they are, as it were, the Roots. The Coats of thefe Sin&?s 9 are furni flied with ftrong Fibres, by means whereof, they are di- lated by the Influx of the Venal Blood, and again contracted with a reciprocal Motion, like the Pulfe of an Artery. See Dura Mater

SION COLLEGE. See College.

SIPHON or SYPHON, in Hydraulicks, a crooked Tube, one Leg or Branch whereof is longer than the other 5 uledin the railing of Fluids, emptying of Veflels,and in various Hy- droftatical Experiments. — The Word in theoriginal Greek, tn^atf, fignifies, limply, Liibe, whence fome apply the Term to common Tubes or Pipes: Wolfitis, particularly defcribes two Veffels under the Name of Siphons ; the one Cylindri- cal in the Middle, and Conical at the two Extremes ; the other Globular in the Middle, with two narrow Tubes fitted t° it, Axis-wife; both ferving to ]take up a Quantity of Water, l£c. and to retain it when up.

But the moft ufeful and celebrated Siphon is as follows : A crooked Tube ABC, (Tab. Hydraulicks Fig. 2.) is provided, of fiich a Length, and with fuch an Angle, as that when the Orifice A, is placed on an horizontal Plane, the Height of A B, may not exceed 30 Foot. jFor common Ufes, a Foot, or half a Foot high, fuffices. If, now, the lefs Arm A B, be immerg'd in Water, or any other Liquid, and the Air be fuck'd out of it by the Aperture C, till the Liquor follow; the Liquor will continue to flow out of the Vefiel, through the Tube B C ; as long as the Aper- ture A is under the Surface of the Liquor. Note, inftead of fucking out the Air ; the Event will be the fame, if the Siphon be at firft filled with the Fluid, and the Aperture C flopp'd with the Finger, till the Aperture A be immerg'd.

The Truth of the Phenomenon is known by abundance of Experiments. Nor is the Reafon of part of it far to feek. In fucking, the Air in the Tube is rarified, and the Equili- brium deflroyed, confequently the Water rauft be raifed into the leffer Leg A B, by the preponderating PrefTure of the Atmofphere.

■ The Siphon being thus filled, the Atmofphere prefles equally on each Extremity thereof; fo as to fuftain an equal Quantity of Water in each Leg : But the Air not being able to iiiflain all the Water in the longer Leg, unlefs it ex- ceed 32 Feet in Height; it will be more than able to fuftain that in the fhorter Leg ; with the Excefs of Force, therefore, will raifc new Water into the fhorter Leg ; which new Water cannot make its way, but by protruding the firft before it. By this means is the Water continually driven out at the longer End, as 'tis continually raiftd at the fhorter.

But Wclfrm t '&iid fome other Authors aflert, that the Watef continues to flow through the Siphon, even when removed under a Receiver, and the Air exhaufied from it. The Re a , fonof this, if it be true, is very difficult to account for.

Some will have it, that there is ftill Air enough left in the evacuated Receiver, to raife the Water to an Inch or two. But as both Mercury and Water are found to fall entirely out of the Torricellian Tube, in Vacuo ; the PrefTure of the thin remaining Air, can never be the Caufe of the Afcent, both of Mercury and Water, in the lefs Leg of the Siphon,

Hence, as the Height of the Siphon is limited to 31 Foot; for this only Reafon, that Air cannot raife Wate? higher ; It does not appear, whether or no we are in the Right in rejecting Hero's Method of carrying Water, by means of a Siphon,- over the Tops of Mountains, into an oppofite Valley. For Hero only orders the Apertures of the Siphon to be ftopp'd, and Water to be pour'd through a Fun- nel into the Angle or Meeting of the Legs, till the Siphon were full ; when, fhutting the Aperture in the Angle, and opening the other two, the Water will continue to flow. Now, if there only need Air for the firft. Rife of the Water into the lefs Leg, not for the Continuation of the Motion ; it were poffible to raile the Water much higher than the Height of the Atmofphere would carry it. — The real Caufe, therefore, of this extraordinary, tho' well-known Pheno- menon ; needs fome further Difijuifition. This is certain, that a Siphon once fet a running, will perfift in its Motion, tho' removed into the moft perfect Vacuum our Air-Pumps will make : Or, if the lower Orifice of a full Siphon be fhut„ and the whole be thus placed in a Receiver, with a Contrivance for opening the Orifice when the Air is exhaufted ; the Water will be all emptied out of the Veflef, as if it had been in open Air.

This, too, is remarkable enough, that the Figure of the Siphon may be varied at plealure, (fee Fig. 3. &cj) provided only the Orifice C be below the Level of the Surface of the Water to be drawn up; but, ftill, the further 'tis diftant from it, the fafter will the Fluid be carried off. And if, in the Courfe of the Flux r the Orifice A be drawn out of the Fluid ; all the Liquor in the Siphon will go out at the lower Orifice C : That in the Leg C B, dragging, as it were, that in the fhorter Leg A B after it. If a fill'd Siphm be lb dif poied, as that both Orifices A and C be in the fame hori- zontal Line; the Fluid will remain pendant in each Leg 5 how unequal fuever the Length of the Legs may be. Fluids, therefore, in Siphons, ieem, as it were, to form one continued Body; fb that the heavier Part defending, like a: Chain, pulls the lighter after it.

Laftly, it muft be obferved, that the Water will flow out, even through a Siphon that is interrupted, by having the Legs A D and F C joyned (Fig. 4, ) together by a much bigger Tube full of Air.

The Sipho Wurtembergicus^ is a very extraordinary Ma- chine of this Kind, performing moftof theThings the common Siphon will not reach, J3.gr. In this, though the Legs be in the fame Level, yet the Water ri fes up the one, and deicends through the other : The Water rifes, even tho' the Aper- ture of the lels Leg be only half immerg'd in Water: the Siphon has its Effect after continuing dry a long time : either of the Apertures being opened,the other remaining fliut for a whole Day, and then open'd,the Water flows our as ufii- ally. Laftly,The Water riles and falls indifferently through either Leg. -- — The Project of this Siphon, was laid by J ordanitsPellerier, and executed at the Expcnce of Prince Frederic Charles Administrator o&Wirtemberg, by his Mathe- matician, Schahackard, who made each Branch 20 Feet long, and 18 Feet apart; the Delcription thereof was publtfhed by Reifelius his Phyfician, which gave Occafion to M. Pap'm to invent another, that did the fame Things, defcribed in the 'Philosophical Tran[aBions ; and which Reifelius, in an- other Paper m the Iranfafffons, ingenuoufly owns to be the very fame with that of Wirtemberg, Its Structure will ap- pear from its Figure ; which is reprefented, Tab. Hyirau- licks, Fig. 5.

SIRE, a Title of Honour in France ; now given to the King only, as a Mark of Soveraignty. In all Placets and Re- quefts, Epiftles, Difcourfes, &c. to the King, he is addrels d under the Title of Sire. Some derive the Word from the Zatm, Hems, Matter .- Of which Opinion feems Will. Bttdeus, who, in (peaking to King Francis I. always calls him Hsr?> q. d. Matter, or Sire, Others derive the Word from &c Greek, kusi©-, Lord ; of which Opinion is Pafqiiier, 'whs* adds, that the ancient Franks gave the Title to God, calling him Sem fire Diex. Others derive the Word from ths Syrian, and maintain, it was firft given to the Merchants who traded to Syria. Menage will have it come from Seniif- Elder ; whence Seigneur, then Seignor, and Sire.,.

Sire was likewife anciently ufed in the fame Senfe Wlt ™ Sieur and Seigneur, and applied to Barons, Gentlemen ana Citizens. The Sire de Jom-ville has wrote the Hii^y oi St, Louis,

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