Page:Cyclopaedia, Chambers - Volume 2.djvu/1042

 YEA

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YEA

Mouth is conftrain'd to follow the fame Motion, as being lined with the fame Membrane.

YCONOMUS: fee Oeconomus.

YDRARGYROS, Hydrargyria, or gttickfilver 5 fee Mercury.

YEAR, Annus, in the full extent of the Word, is a Syflem or Cycle of feveral Months ; ufually twelve. See Cycle and Month.

Others define Tear, in the general, a Period, or Space of Time, meafured by the Revolution of fome Cceleflial Body in its Orbit. See Time and Period.

Thus, the Time wherein the fixed Stars make a Revolu- tion, is call'd the great Tear. And the Times wherein Jupiter, Saturn, the Sun, Moon, &c. finifh their Revo- lutions, and return to the fame Point of the Zodiac, are refpecfively call'd the Tears of Jupiter, and Saturn, the Solar, and the Lunar Tears. See Son, Moon, Planet, Ejc. Solar Yilar, LunarYs.hR, (gc.

Year, properly, and by way of eminence fo call'd, is the Solar Tear ; or the Space of Time wherein the Sun moves thro' the Ecliptic. See Ecliptic.

This, by the Obfervations of CaJJini, Biaixhini, and de la Hire, contains 3S5 Days, 5 Hours, and 49 Minutes; which is the Quantity of the Tear affumed by the Authors of the Gregorian Calendar. See Solar Year.

But, in the Civil, or popular Account, this Tear only contains 3S5 Days ; except every fourth, which contains 3S6. See CivilYn.hu..

The Viciffitude of Seafons feems to have given occafion to the firft Inftitution of the Year. Man, naturally cu- rious to know the Caufe of that Diverfity, foon found it was the proximity and diftance of the Sun ; and upon this, gave the Name Tear to the Space of Time wherein that Luminary performing his whole Courfe, return'd to the fame Point of his Orbit. See Season.

And hence, as it was on account of the Seafons, in a great meafure, that the Tear wasinftituted ; their chief Regard and Attention, was, that the fame parts of the Tear i~hou\A always correfpond to the fame Seafons ; i. c. that the be- ginning of the Tear fhould always be when the Sun was in the fame Point of his Orbit ; and that they [tfhould keep pace, come round, and end together.

This different Nations aim'd to attain by different ways; making the Tear to commence from different Points of the Zodiac ; and even the time of his Progrefs different. So that fome of their Tears were much more perfect than others, but none of them quite juft ; i. e. none of them but whole Parts fhifted with regard to the Parts of the Sun's Courfe.

'Twas the Egyptians, if we may credit Herodotus, that firfl form'd the Tear, making it to contain 3<fo Days, which they fubdivided into 12 Months.

Mercury Tripnegiftus added 5 Days more to the Account

' And n this footing, Thales is faid to have inftitu-

ted the Tear among the Greeks. Tho' that Porm of the

Tear did not hold throughout all Greece Add, that

the JcxMi, Syrian, Roman, Verfian, Ethiopia, Arabic, &c. Tears, were all different.

In effect, confideting the poor State of Aflronomy in thofe Apes, 'tis no wonder different People fhould difagree

in the Calculus of the Sun's Courfe We are even affiired

by TJiod. Siculus, Lib. 1. 'Plutarch in Numa, and 'Pliny, Lib. VII. c. 48. that the Egyptian Tear itfelf was at firit very different from that now reprefented. See Egyptian Year, Roman Year, Jeviifb Year, &c.

Various Forms of Solar and Lunar Years.

Solar Year is the Interval of Time wherein theSunfini- fhes his Courfe through the Zodiac 5 or, wherein he returns to the fame Point thereof whence he had depatted. See Sun.

This, according to our Account, is 355 Days, 5 Hours, 49 Minutes ; tho' fome Aftronomers make it a few Seconds, and fume a whole Minute lefs; as Kepler, for inftance,who makes it 3S5 Days, 5 Houts, 48 Minutes, 57 Seconds, 39 Thirds : Ricciolus, %6s Days, 5 Hours, 48 Minutes ; and T'ychoSrahe 3«s Days, ; Hours, 48 Minutes.

The Solar Tear is either Aftronomical, or Civil.

The Solar Aftronomical Ye ar is that determined pre- cifely by the Obfervations of Aflronomy; and is of two kinds, Tropical, and Siderial or Jftral.

The Tropical, or Natural Year, is the Time which the Sun employs in paffing through the Zodiac ; which, as before obferved, is 3«5 Days, 5 Hours, 40 Minutes.

The Siderial or JjlralYx.hR, is the Space of Time wherein the Sun going from any fixed Star, returns to the

fame This^confifls of 365 Days, if Hours, ioMinures.

See Siderial.

Civil Year is that Form of Tear which each Nation has contrived to compute Time by : or, the Civil, is the Tro- pical Tear confidet'd as only confifling of a certain Number ef whole Days ; the odd Hours and Minutes being fet afide,

to render the Computation of Time, in the common occa- uons ot Life, more eafy. SeeCiviL.

Hence, as the 'tropical Tear is 5<r; Days, 5 Hours, 49 Minutes the Civil Tear is 3S5 Days. And hence, alfo, as tisneceffary to keep pace with the Heavens, it is required that every fourth Year confifl of --,66 Days-

Hence, laftly, the Civil Tear is either Common or Sif- fextile.

The Common Civil Year is that confifling of 30-5 Days. This, therefore, has feven Months of 30 Days each and five of 51 Days.

Bijfextile or Leap Year is that confifling of 366 Days; or has one Day extraordinary, which Day is call'd the In- tcrcalary or SiJJextileTJay. SjcIntercalary.

This Intercalary, or additional Day to every fourth Tear, was firft appointed by Julius Cusfar, who, to make the Civil Tears keep pace with the Tropical ones, conttived, that the 6 Hours which the former came fhort of the latter, fhoukl, in four Years, make a whole Day, and be added after the 23d of February, which was their fixth of the Calends of March.

Hence, ar, in that Tear, they reckon'd this Day twice over, or had bisfexto Calendas ; the Tear itfelf came to be call'd Sis Sextus and Bijfextile.

The Intercalary Day, however, among us, is not got in by telling the 24th of February twice over ; but by adding a Day after the 28th of February ; which by this means,that Tear, comes to contain 29 Days. See Bissextile.

A further Reformation in this Tear was made by Pope Gregory. See Gregorian Year.

LunarYvhRh a Syflem of 1= Lunar Months. See Lunar.

Hence, from the two kinds of Synodical Lunar Months, there arife two kinds of Lunar Tears, the one Aftronomical, the other Civil.

Lunar Aftronomical Year confifts of twelve Lunar Sy- nodical Months; and therefore contains 354 Days, 8 Hours, 48 Minutes, 38 Seconds, 11 Thirds. See Synodical.

Lunar Civil Year, is either Common, or Embolimic.

T*he Common Lunar Year confifts of twelve Lunar Civil Months; and therefore contains 3 54 Days.

"The Embolim ic or Intercalary Year confifts of 13 Lunar Civil Months ; and therefore contains 384 Days. See Embolimic.

Note, as the difference between the common Lunar Civil Tear and the Tropical Tear, is 11 Days, 5 Hours, and 49 Minutes ; to have the former keep pace with the latter, there are 34 Months of 50 Days, and 4 Months of 31 Days each, to be inferted in every ico Lunar Tears ; which ftill leave behind 'em an Appendix of 4 Hours, 2 1 Minutes,which in fix Centufies make nearly a day more.

Thus far' we have confider'd Tears and Months with a view to the Principles of Aflronomy, whereon the divifion is founded. By this, the various Forms of Civil Tears that have antiently obtain'd, or Hill doobtain, in divers Nations, are to be examined.

Various Forms of Civil Years.

Antient Roman Year, was the Lunar Tear, which, as firft fettled by Romulus, only confined of tea Months ; viz. 1. March, containing 31 Days. 2. April, 30. 3. May, 31. 4. June, 30. 5. guintilis, 31. 6. Sextilis, 30. 7. September, 30. 8. Offo&r, 51. 9. November, 30 10. December, 30 ; in all 304 Days, which came fhort of the true Lunar Tcarby 50 Days, and of the Solar by 61 Days.

Hence, the beginning of Romulus's Tear was vague, and unfix'd to any precife Seafon ; which Inconvenience to re- move, that Prince order'd fo many days to be added yearly as would make the State of the Heavens correfpond to the firft Month, without incorporating thefe additional Days, or calling them by the Name of any Month.

Numa 'Pompilius corrected this irregular Conflfrution of the Tear, and compofed two new Months, January and February, of the days that were ufed to be added to the for- mer Tear — Thus, Nairn's Tear confided of twelve Months, viz. I.January, containing 29 Days; 2. February, 28; 3. March, 31 ; 4. April, 29 ; 5- May, 31. 6. June, 29 ; 7. guintilis, 31 ; 8. Sextilis, 29 ; 9. September, 29; 10. Offiotser, 31 ; 11. November, 29 ; 12. December, 29 ; in all 355 Days, which exceeds thequantity ofa Lunar Civil Tear by one day ; and that of a Lunar Aftronomical Tear by 1 5 Hours, 11 Minutes, 24 Seconds ; but came fhort of the common Solar Tear by ten Days; fo that its beginning was vague, and unfix'd.

Numa, however, defiring to have it fixed to the "Winter- Solflice, ordered 22 Days to be Intercalated it) February every fecond Tear, 23 every fourth, 22 every fixth, and 23 every eighth Tear.

But this Rule failing to keep Matters even, recourfe was

had to a new way of Intercalating ; and infteadof 23 Days

every eighth Tear, only 15 were added ; and the Care of

the whole committed to the Tontifex Maximus ; who,

Fffff neg-