Page:Cyclopaedia, Chambers - Volume 2.djvu/1015

 WED

length, and called the Warpi, and others drawn a-crofs them call'd the Woof- See Texture, Woof, Warp, &c.

Spider's-^^n, or Co^-Web, is a very delicate and won- derful Tiflue, which that Infect (pins out of its own Bowels ; ferving it as a fort of Toil, or Net to catch Flies, ®c. withal. ,

For the manner wherein the Spider fpms his Web ; the admirable Mechanifm of the 'Parts fubfervient thereto, and the Ufes thereof ; fee Silk.

Dr. Lifter tells us, that attending nearly to a Spider weaving a Net, he obferv'd it fuddenly to defift in the mid- work, and turning its Tail to the Wind, darted out a Thread, with the violence and ftream we fee Water fpout out of a Jet : This Thread, taken up by the Wind, was immediately emitted fome Fathoms long ; ftill iffuing out of the Belly of the Animal.— By and by the Spider leap'd into the Air ; and the Thread mounted her up fwiftly. — After this Difcovery, he made the like Obfervation in near thirty different forts of Spiders ; and found the Air fill'd with young and old, failing on their Threads, and doubtlefs feiz- ing Gnats and other Infers in their paffage : there being of- ten, manifeft Signs of Slaughter, Legs and Wings of Flies,S?c. on thefe Threads, as well as in their Webs below.

Dr. Hnlfi difcover'd the fame thing about the fame time. — In a Letter of Dr. Lifter to Mr. Ray, he thinks there is a fair Hint of the darting of Spiders in Ariftotle, Hift. An. Lib. IX. cap. 35. and in 'Pliny, Lib. II. cap. 24. But for their failing, the Antients are filent, and thinks it was firft feen by him.— In another Letter ro Mr. Ray, dated Jan. l6-jo, (peaking of the Height Spiders are apt to fly to, he fays, " Laft OBober, ike. I took notice that the Air was " very full of Webs ; I forthwith mounted to the Top of " the higheft Steeple on the Minfter, [in Tork'] and could " there difcern era yet exceeding high above me."

WEDGE, Cunev.s, in Mechanicks, the laft of the five Powers or fimple Machines. See Mechanical 'Power.

The Wedge is a triangular Prifm, whofe Bafes are equi- lateral acute-angled Triangles. See Prism.

Authors are divided abour rhc Principle whence the Wedge derives its Power. — Ariftotle confiders it as two Levers of the full kind, inclined toward each other, and airing oppo- fitc ways.— G/«V& Ubaldus, Merfenmis, &c. will have 'em Levers of the fecond kind.— But Fr. de Zanis fhews, it can- not be reduced to any Lever at all. See Lever.

Others refer the Wedge to the inclined Plane. Others,

again, with de Stair, deny the Wedge to have fcarce any Force at all ; and afcribe much the greateft Part to the Mai- iet that drives it.

But the lateft Authors agree to refer the Effect of the Wedge to the Cochlea, or Screw. See Screw.

Its Docfrine is contain'd in this Propofition. If a

Tower be applied to a Wedge, in fuch manner as that the Line of2)ire3ion C D, (Tab. Mechanicks, Fig. 53.) perpen- dicular to A B, is to the Refi fiance to be overcome, as A B to C D ; the Tower will be equal to the Refiftance.

Or thus : If the Power dircSly applied to the Head of the Wedge, be to the Refiftance to be overcome by the Wedge, as the Thiehtefs of the Wedge is to its Height ; then the Power will be equivalent to its Refiftance ; and if increaf- ed, will overcome it.

For the Firmnefs whereby the Parts of the Obftacle, fup- pofc Wood, adhere to one another, is the Refiftance to be overcome by the Wedge. See Firmness, and Resistance.

Now, it is evident, that while the Wedge is drove into the Wood, the Way or Length it has gone is B A, (Fig. 54.) and D C is the Way or Length gone in the fame time by the Impediment ; that is, the Parts C and D of the Wood, are lb far divided afunder : and according as the Wedge is drove down farther and farther along irs Height ; fo the Parts C and D of the Wood, are divided more and more along rhe Thicknel's of the Wedge.

Hence, if the Thicknefs of the Wedge (that is, the Way of the Impediment, and confequently its Velocity) be to the Height of the Wedge, (that is, the Way, and confequently the Velocity of the" Power) as the Power to the Impediment or Refiftance ; then the Momentum of the Power and rhe Impediment, will be equal the one to the other ; and confe- quently, the Power, being increafed, will overcome the Re- fiftance.

Hence, i°, As the Power equivalent to half the Refiftance, is to it as a b to Kb, that is, as the whole Sine to the Tan- gent of halT the Angle of the Wedge, a kb. — And, i°, as the Tangent of a lefs Angle is lefs than that of a grearer, the Power mutt have a greater Proportion to half the Refif- tance if the Angle be greater, than if lefs. — Confequently, the acuter the Wedge is, the more does it increafe the Power.

To the Wedge may be refer'd all Edge-Tools, and Inftru- ments which have a /harp Point, in order to cut, cleave, flit, chop, pierce, bore, or the like ; as Knives, Hatchets, Swords, Bodkins, &c.

WEDLOCK. See Marriage, Wife, Husband, igc.

[ 358 ] WEE

WEDNESDAY. See Month, Day, $$c.

X/^-Wedneseay. See Asn-Wednefday.

WEED, a common Name for all rank and wild Herbs, that grow of themfelves, to the Detriment of other ufeful Herbs they grow among. See Plant, Herb, &c.

i^/Z/erVWEED. See Thistle, or Teazle.

Weep, in the Miners Language, is the Degeneracy of a Load or Vein of fine Metal, into an ufelefs Marcafite. See Vein, Mine, Metal, Marcasite, &c.

Weeds, are alfo a peculiar Habit, wore by the Relicts of Perfons deceas'd, by way of Mourning. See Mourning.

WEEK, Septimana, Hebdomada, in Chronology, a Di- vifion of Time, comprising feven Days. See Time, and Day.

The Origin of this Divifion of Weeks, or. of computing Time by Sevenths, is greatly controverted. — Some will have it to take its rife from the four Quarters or Intervals of the Moon, between her Change of Phafes, which being about fe- ven Days diftant, gave occafion to the Diviiion. See Moon, Quarter, $$c.

Be this as it will, the Divifion is certainly very antient. — ■ The Syrians, Egyptians, and moft of the Oriental Nations, appear to have ufed it from all Antiquity : tho it did not get Footing in the Weft, tillChriftianity brought it in: The Romans reckoning their Days, not by Sevenths, but by Ninths ; and the antient Greeks by Decads, or Tenths.

Indeed, the Jews divided their Time by Weeks, but it was upon a different Principle from the other Eaftern Na- tions. God himfelf having appointed 'em to work fix Days, and to reft the Seventh ; in order to keep up the Senfe and Remembrance of the Creation, which being effected in fix Days, he refted the feventh. See Sabbath.

Some Authors will even have the ufe of Weeks among the other Eaftern Nations, to have proceeded from the Jews j but with little Appearance of Probability. — 'Tis with better Reafon that others fuppofe the Ufe of Weeks among the Heathens of the Eaft, to be a Remain of the Tradition of the Creation, which they had ftill retain'd with divers others.

This is the Opinion of Grotius, %)e Veritai. Relig. Cbriji. Lib. I. who likewife proves, that not only rhro'- out the Eaft, but even among the Greeks, Italians, Celt#, Sclavi, and even the Romans themfelves, the Days were divided into Weeks $ and that the feventh Day was in extraordinary Veneration. — This appears from Jofepb. adv. Appionem II. ^Philo de Creatione, Clem. Alexand. Strom.

Lib. V.. Tho lielmoldus, Lib. I. cap. 84. <Philoflra-

tus,'~L\h. III. cap. 13. Dion. Lib. XXXVIII. Tibullus, Lu- cian, Homer, Callimachus, Suetonius, Herodotus, &c. who mention the Cuftom as very antient, fuppofe it to have been deriv'd from the Egyptians.

The Days of the Week were denominated by the Jews

from the Order of their Succeffion from the Sabbath. ■

Thus, the Day next after the Sabbath they call'd the firft of the Sabbath, the next the fecond of the Sabbath, and fo of the reft 5 except the iixth, which they call'd 'Parajceve or Preparation of the Sabbath. See Parasceve.

The like Method is ftill kept up by the Chriftian Arabs, 'Per/tans, Ethiopians, &c. — The antient Heathens denomi- nated the Days of the Week from the feven Planets ; which Names are ftill generally retain'd among the Chriftians of the Y# e 0. — Thus, the firft Day was call'd Sun-day, Dies Solis 5 the fecond Mon-day, Dies Lun#, &c. a Practice the more natural on Dion's Principle, who fays, The Egyptians took the Divifion of the Week it felf from the feven Planets.

In effect, the true Reafon of thefe Denominations is founded in Aftrology. — For the Aftrologers, diitributing the Government and Direction of all the Hours in the Week among the feven Planets, Tj V c? © 9 5 and ^) j fo as that the Government of the firft Hour of the firft Day fell to Saturn, that of the fecond to Jupiter, &c. They gave each Day the Name of the Planet which prefided over the firft Hour thereof: and that, according to the Order fpecify'd above ; and which is included in the following Technical Verfe.

Toft SIM SUM feqnitur, pallida 'Luna fubefl.

Wherein, the Capital Letters, SIM SUM and L, are the initial Letters of the Planets. — Thus, the Order of the Pla- nets in the Week, has little Relation to the Order in which they follow in the Heavens : The former being founded on an imaginary Power each Planet has in its turn on the firft Hour of each Day. See Planet, Hour, House, Ascen- dent, Horoscope, &c.

Dion. Caffius gives another Reafon of the Denomination, fetch'd from the celeftial Harmony.— For it being obferv'd that the Harmony of the Diateffaron, which confifts in the Ratio of 4 to 3, is of great force and effect in Mufick ; it was judg'd meet to proceed directly from Saturn to the Sun ; becaufe there are three Planets between Saturn and the Sun, and four from the Sun to the Moon. See Diatessaron,

Harmony of the Spheres^ &c.

To