Page:Cyclopaedia, Chambers - Volume 1.djvu/1037

 HYG

£F, and FG, be parallel to the Horizon, as exprefs'd in the prefent Figure, or perpendicular to the fame.

The Advantage of this, above the former Hygrometer, is, that we have a greater Length of Cord in the ft me Com- pafs : And the longer the Cord, the greater its Contraction and Dilatation,

Or thus : Faflen a hempen Cord or Fiddle-firing AB (Fig; 9.) to an Iron Hook, and let the other End, B, deicend upon the Mid- dle of a horizontal Board or Table EF. Near B hang a leaden Weight of a Pound, C, and fit an Index CG. Laitly, from the Center B defcribe a Circle ; which divide into any Number of equal Parts.

Now, it is matter of Obfervation, that a Cord or Gut twills itfelf as it is moiften'd, and un twills again as it dries. — Mr. Molyneiix, Secretary of the ^Dublin Society, writes, that he could perceive this alternate Twilling and Untwiffing in a Cord, by only breathing en it eight or ten times, and then applying a Candle toward it. Hence, upon an Increafe or Decreafe of the Humidity of the Air, the Index will fhew the Quantity of Twilling or Untwilling ; and, confe- quently, the Increment or Decrement of Humidity or Siccity,

Or thus : Fatten one End of a Cord or Fiddle-firing H I (Fig. ro.) to a Hook H ; and to the other End fallen a Ball K, of a Pound Weight. Draw two concentric Circles on the Bail, and divide them into any Number of equal Parts. Fit a Style or Index NO into a proper Support N, fo as the Ex- tremity O may almoll touch the Divifions of the Ball.

Here, the Cord or Gut twilling and untwilling, as in the former Cafe, will indicate the Change of Moillure, &C. by the fucceffive Application of feveral Divifions of the Circles to the Index.

Or thus : Provide two wooden Frames AB and CD, (Fig. 11.) with Grooves therein ; and between thofe Grooves fit two thm Leaves of AfH AEFC, and GEDH, fo as they may eafily flide either Way. At the Extremes of the Frames A, B, C, D, confine the Leaves with Nails, leaving between them the Space EGHF, about an Inch wide. On I fallen a Slip of Brafs dented, IK 3 and in L a little dented Wheel, upon whofc Axis, on the other Side of the Machine, an Index is to be put. Laflly, from the Centre of the Axis, on the fame Side, draw a Circle, and divide it into any Number of equal Parts.

Now, it being found by Experience, that Allien Wood readily imbibes the Molfture of the Air, and fwclls there- with ; and as that Moillure flackens, fhrinks again ; upon any Increafe of the Moillure of the Air, the two Leaves AF and BH growing turgid, will approach nearer each other : And, again, as the Moillure abates, they will fhrink, and again recede. — Hence, as the Dillance oi the Leaves can neither be increas'd nor diminifh'd without turning the Wheel L, the Index will point out the Changes in refpecl of Humidity and Siccity.

Or thus : It is to be noted, that all the Hygrometers above defcrib'd become fenfibly lefs and lefs accurate ; and, at length, under- go no fenfible Alteration at all from the Humidity of the Air. The following one is much more lailing.

Take the Mamfcofte, defcrib'd under that Article, and, inftead of the exhaufted Ball E, (Fig. 12.) fubflitute a Spunge, or other Body, which eafily imbibes Moiflure. To prepare the Spunge, it may be ncceffary firft to wa/h it in Water 5 and when dry again, in Water or Vinegar wherein Sal Ammoniac or Salt of Tartar has been diffbly'd, and let it dry again.

Now, if the Air become moid, the Spunge growing heavier, will preponderate 5 if dry, the Spunge will be hoiil- ed up ; and, confequently, the Index will fliew the Increafe or Decreafe of Humidity of the Air.

In the lafi mention'd Hygrofcope, Mr. Gould, in the Wilo- fopl'ical Tranfaffions, inftead of a Spunge, recommends Oil of Vitriol, which is found to grow infenfibly lighter or heavier, in Proportion to the lefler or greater Quantity of Moillure it imbibes from the Air 5 fo that being fatiated in the moiflefl Weather, it afterwards retains or lofts its acquir'd Weight, as the Air proves more or lefs moid. — The Alte- ration is fo great, that in the Space of 57 Days, it has been known to change its Weight from three Drams to nine ; and has fhifted an Index or Tongue of a Ballance 30 Degrees. — A fingle Grain, after its full Increafe, has vary'd its Equili- brium fo fenfibly, that the Tongue of a Ballance only an Inch and half Ion:*, defcrib'd an Arch one Third of an Inch in Compafs 5 which Arch would have been almoll three Inches, if the Tongue had been one Foot, even with fo fmall a Quantity of Liquor; confequently, if more Liquor ex- panded under a large Smface were us'd, a Pair of Scales might afford as nice a HxiiTofcofie as any yet invented. — The fame Author fuggefts, that Oil of Sulphur per Campa-

( 2 7$ )

H Y M

nam, or Oil of Tartar per Deliquium, or the Liquor of fix'd Nitre, might be fubllituted in lieu of the Oil" of

Vitriol. 1

This Ballance may be contriv'd two Ways ; by either hav- ing the Pin in the Middle of the Beam, with a flender Tongue a Foot and half long, pointing to the Divifions on an arched Plate ; as reprefentcd in Fig. 12.

Or, the Scale with the Liquor may be hung to the Point of the Beam near the Pin, and the other Extreme be made fo long, as to defcribe a large Arch on a Board piae'd for the" Purpofe 5 as reprefented in Fig. 13.

■ From a Series of Z^aj^ra/'Obfervations made with an Apparatus of Deal Wood, defcrib'd in the Wsilofophkal TranfaBions,Mt.Ccniers concludes; i°.ThattheWood (brinks moll in Summer, and fwells moll in Winter 5 but is mofi liable to change at Spring and Fall. 2 . That this Motion happens chiefly in the Day-time ; there being fcarce any Va- riation in the Night. 3°. That there is a Motion even in dry Weather ; the Wood fwelling in the Forenoon, and fhrink- ing in the Afternoon. 45. The Wood, by Night as well as Day, ufually flirinks when the Wind is in the North, North- Eait, and Eafl, in Winter and Summer. <j°. By conflant Obfervation of the Motion and Refl of the Wood, with the Help of a Thermometer, one may tell the Situation of the Wind without a Weather-cock. See Wind,

He adds, that the Time of the Year may be known by it ; for in Spring it moves quicker, and more than in Winter ; in Summer it is more fhrunk than in Spring ; and h's lefs Motion in Autumn than in Summer. Sec Season, Wea- ther, &c.

HYGROSCOPE, is commonly us'd in the fame Senfe with Hygrometer. See Hycrcmeter.

Wolfius, however, regarding the Etymology of the Word, makes fome Difference. According to him", the Hvgrofcope only fhews the Alterations of the Air in refpecf: of Humidity and Drynefs 5 but the Hygrometer meafures them. A Hy- grofcope, therefore, is a lefs accurate Hygrometer.

The Word is compounded of u^?©-, moiil, and ff-/.o-ma t video, fpeclo, I fee, I conilder.

HYLE, or Hylec, among Akhymifis, is. their firft Mat- ter ; or it is Matter confider'd as produced by Nature herfelf 5 call'd alfo Chaos. See Matter, Alchymy, &c.

The Word is Greek, 3\n, which fignifies Matter.

HYLEG, or Hylech, in A Urology, an Arabic Term for a Planet ; which in a Man's Nativity becomes the Mode- rator and Signincator of Life. Sec Nativity, Signifi-

CATOR, i§C.

HYLEGIAL Places* among Aftrologers, are fuch, in which, when a Planet happens to be fet, it may be faid to be fit to have the Government of Life attributed thereto.

HYLOBII, or Hyloeians, a Se& of Indian Philoso- phers, thus denominated by the Greeks, in regard they re- tir'd to Forefls, to be more at Leifure for the Contemplation of Nature.

The Name is compounded of the Greek-, Saw, which, be- fide Matter, fignifies alfo Wood, Forefl ; and 3/0", Life.

HYMEN, in Poetry, a Term of Invocation. — Hyrnenot Hyineiimis, is properly a fabulous Divinity, fuppos'd by the Ancients to prefide over Marriages ; and who accordingly was invok'd in Epithalamiums and other matrimonial Ceremonies, under this Formula, Hymen Hymen£e.

The Poets generally give this Deity a Chaplet of Rofes ; and reprefent him as it were diflolv'd and enervated with Pleafures^ drefs'd in a yellow Robe, and Shoes of the fame Colour ; with a Torch in his Hand. — Catullus^ in one of his Epigrams, addrefll's him thus :

ftmbm %

Suave olentis Amaraci.

It was for this Reafon, that the new marry'd Couple bore Garlands of Flowers on the Wedding-Day : Which Cufcom alfo obtain'd among the Hebrews. ; and even among the Chrillians, during the firfl Ages of the Church, as appears from T'ertullian, de Corona MHitari, where he fays, Coronant &> Ntptie Sponfos. — S. Cbryfoftom likewife mentions thefe Crowns of Flowers - y and to this Day the Greeks call Marri- age r£3«v««4>, in refpecl: of this Crown or Garland. See Crown and Garland.

Hymen, in Anatomy, is a thin Membrane or Skin, re- fembling a Piece of fine Parchment, fuppos'd to be flretch'd in the Neck of the Womb of Virgins, below the Nympbae; and to be broke when they are deflower'd ; an Effufion of Blood following the Breach. See Defloration and Vir- gin.

The Hymen is generally Iook'd upon as the Tell of Virgi- nity ; and when broke, or withdrawn, fhews, that thePcrfbn is not in a State of Innocence. — This Notion is very ancient. Among the Hehrc-ivs, it was the Cuflom for the Parents to fave the Blood fhed on this Occafion, as a Token of the Vir- ginity of their Daughter ; and to fend the Sheets, next Day, to the Husband's Relations. And the like is iaid to be flill

praifis'd