Page:Cyclopaedia, Chambers - Volume 2.djvu/44

 IN

C 400 )

IN

makes to him felt" 5 and it muft be own'd, that this Figure adds an uncommon Brisknefs, Action and Force to Dif- courfe.

Interrogation, in Grammar, is a Point which fcrves to diftinguifh fuch Farts of a Difcourfe, where the Author fpeaks as if he were asking Queftions. Its Form is this ?

INTERRUPTION, is the fume with Disjunction of Proportion in Geometry, it is noted thus (: ■■) and figni- fieth the breaking off of the Ratio in the middle of four disjunct or difcrete Proportionals, as A : B :: C : Dj that is, as A is to B io is C to D.

Intei nftlon is alfo a Figure in Rhetoric, wherein a Per- fon breaks off his Difcourfe fuddenly, to fliew fome Paf- ilon.

INTERSECTION, in Mathematics, fignifies the Point or Line wherein two Lines or two Planes cut each other. Thus wc fay, that the mutual Int'erfeUion of two Planes is a Right Line. The Centre of a Circle is in the Interjec- tion of two Diameters. The Central Point of a regu- lar or irregular Figure of four Sides is the Point of Inter- feron of the two Diagonals. The Equinox happens when the Sun is in the Interjection of the Equator and Ecliptic.

INTERSOILING, in Husbandry, is laying one kind of Soil or Mould upon another 5 as Clay on Sand, Sand on Earth, &c.

INTERSPINALES COLLI, the Name of five Pair of finall Mufcles difcover'd by Mr. Cozuper ■■> and by him fo call'd from their Pofition. Theyarile from each dou- ble Proccis of the Spine of the Neck, and run from the upper one to the next below, into which they are inferred. They fcrve to approximate and draw together the Vertebra of the Neck, and are more elpecially proper to this Part, as having both Origin and Infertion in it.

INTERSTELLAR, is a Word ufed by fome Authors to exprefs thofe Parts of the Univerfe that are without and beyond our Solar Syfiem ; in which are fuppofed to be fevcral other Syllcms of Planets moving round the fixed Stars as the Centers of their refpective Motions : And if it be true, as it is not improbable, That each fixed Star is thus a Sun to fome habitable Orbs, that move round it, the Interftetiar World will be infinitely the grea- ter part of the Univerfe.

INTERT1ES, or 1NTERDUCES, in Architecture, arc thofe fmall Pieces of Timber that lie horizontally be- twixt the Summers, or betwixt them and the Sell or Kefon.

INTERTRANSYERSALES COLLI : Certain Muf- cles between the tranfverfe Proceffes of the Vertebra of the Neck, of the fame Size and Figure with the Interfpi- vales, and obferved by the fame Author. Sec Pbilojvph. TranfaB. vol. 2:1. f. 192.

INTERVAL, the Diflance or Space between two Ex- tremes, either of Time or Place. The Word comes from the Latin Jntervalkm, which, according to Ijidorc, fignifies the Space inter Foffam {$ Mumm, between the Ditch and the Wall. Others fay, that the Slakes or Piles, driven into the Ground in the antient Roman Bulwarks, were cal- led Va.Ua, 'and the Intcrfticcs or Vacancy between them Jnter-vaUa.

INTERVAL, in Mufic, is the Difference between two Sounds in rcinect of Acute and Grave, or that imaginary Space terminated by two Sounds differing m Acutenefs or Gravity. When two or more Sounds are compared in this Relation, they are either equal or unequal in the Degree of Tune. Such as are equal are call'd Unifons, with regard to each other, as having one Tune -, the other being at a diflance from each other, conflitute what we call an Interval in Mufic, which is properly the Ditfance in Tune between two Sounds. Intervals are dillinguiih'd into Simple and Compound. A fimple Interval is without Parts or Divifion, a Compound con lifts of fevcral lcfTer Intervals. But this DHiinclion regards Practice only, becaufe there is really no fuch thing as a leafl Interval. Befides, by a fimple Interval is not meant here the leafl praclifed, but fuch as tho it were equal to two or more Idler which are in ufe, yet when we would make a Sound move fo far up or down, we always pafs immediately from one of its Terms to the other. What is meant then by a compound Interval, will be very plain : It is fuch, whofe Terms are in Practice taken either in immediate Suc- ceflion," or fuch where the Sound is made to rife and fall from the one to the other, by touching fome intermediate Degrees ; fo that the whole becomes a Competition of all the Intervals from one Extreme to the other. What we here call a fimple Interval, the Antients call'd a Viaflem, and the Compound they call'd a Syfiem. Each of thefe has Differences; even of the Simple there are fome greater, and others lefs : bur they are always Difcord ; but of the Compound or Syfiem, fome are Concord, others Difcord. Unifons, 'tis plain, cannot pofftbly have any Variety 5 for where there is no difference, as in Unifonance, which flows from a Relation of Equality, 'tis plain there can be

no Diftinflion : Unifons therefore muft all be Concords. But an Interval depending on a Difference of Tune, or a Relation of Inequality, admits of Variety ; and fo the Terms of every Interval, according to their particular Re- lation or Difference, make either Concord or Difcord. Some indeed have retrained the word Concord to Inter- vals, making it include a Difference in Tune, but this is precarious; for as the word Concord fignifies an Agree- ment of Sounds, 'tis certainly applicable to Unifons in the fir ft Degree : Intervals, 'tis plain, may differ in Magni- tude, and there may be an infinite Variety according to the poftible Degrees of Tunc ; for there is no Difference fo great or little, but a greater or a lefs may poflibly be conceived. 'Tis true, with regard to Practice, there arc Limits which are the greateft and leaft Intervals our Ears are Judges of, and which may be actually produced by Voice or Inflrument.

The Degrees of Tune are proportional to the Num- bers of Vibrations of the fonorous Body in a given Time* or the Velocity of their Cottffes and Recourfes. Now thefe Differences in Tune conflitute, as has been already faid, the Intervals in Mufic ; thefe therefore .muft be greater or lefs, as the Differences are 5 and 'tis the Quantity of thefe, which is the Subject of the Mathe- matical Part of Mufic. Thofe Intervals are meafured not in the fimple Differences or Arithmetical Ratio's of the Numbers exprefling the Lengths or Vibrations, but in their Geometric Ratio's j fo that the fame Inter- val depends on the fame Geometrical Ratio, and vice vcrfi. It is however to be obferved, that in comparing the Equality of Intervals, the Ratio's expreffmg them mutt be all of one Species j otherwife this Abfurdity will fol- low, that the fame two Sounds may make different Inter- vals. To defcribe the particular Methods of mcafuring the Inequality of Intervals, would be too tedious : this one Rule may be obferved, that, to determine in general*, which of two or snore Intervals' are the greateft, take all the Ratio's as proper Fractions, and the leaft Fraction will be the greateft Interval.

The Antients were extremely divided about the mea- furing of Intervals. Pythagoras and his Followers meafur'd them by the Ratio's of Numbers. They fuppofed the Differences of Gravity and Acutenefs to depend on the different Velocities of the Motion that caufes Sound 5 and thought, therefore, that they could only be accurately mea- fured by the Ratio's of thofe Velocities. Which Ratio's were fir ft investigated by Pythagoras, on occafion of his patting by a Smith's Shop, and obferving a Concord be- twixt the Sounds of Hammers flriking on the Anvil. jirijloxems oppofed this. He thought Rcafon and Ma- thematics had nothing to do in the cafe, and that Senfe was the only Judge in the Difpute 5 the other being too fubtile to be of any ufe. He therefore determined the Sve, 5th, and 4th, which are the moll fimple. Concords, by die Ear; and by the Difference of the 4th and 5th, he found out the Tone.- which once fettled as an Interval the Ear could judge of, he pretended to meafurc every Interval bv various Additions and Subftraclicns made -of rhefe mentioned one with another: But this Method is very inaccurate. Ptolemy keeps a middle Courfc betwixt the two. He finds fault with the one for defpifing Rea- fon, and with the other for excluding Senfe ; and fhews how thefe two may mutually affift each other in this Matter. See Tone, &c.

INTESTATE, a Perfon who dies without making a. Will. An Heir ab Intefiato, is a Perfon who inherits an Eftatc by fome other Right, than that of Will or Tefta- ment. Heretofore, thofe who died Inteftate, were held infamous, and accurfed ; in regard, by the Canons of fe- vcral Councils, every Perfon was injoin'd to bequeath a part of his Eflate (and Matthew Paris fays it was at leaft to be a tenth part) to the Church, for the Safety of his Soul j which, a Perfon who neglected to make aWill, and to leave this Legacy to the Church, wasjudg'd to hi abandon'd. Several Councils took on them to comma., the Priefls to follicite dying Perfons to be charitable — the Church j and this they did fo carneftly, that Abfolu- tion and the Viaticum were denied to thofe whom they could not prevail on j fo that they made no difference between thefe Intcftates and Sclf-Murdercrs : and they were alike denied ChrifKan Eurial. Du Cange adds, that all who died without Abfolution, without'recciving the Vi- aticum* and without leaving Alms to the Church (even tho they died fuddenly) had their Effects feiz'd and con- fifcated'to the Ufe of the Church, the BilTiop, $$c.

In our En^hjh Law there are two kinds of Jnteftatcs- ; the one dc faSo, which are thofe who make no Will at all, the other de jure, which are thofe who make a Will ; but it is null and veld, either from the Executors refuting to act, or from fome other Caufe in which he is judg'd to die iuteftate.

INTESTINE

ave and