Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/1000

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nuate the blood and preferve its heat, and by both thefe keep up the motion of the heart. See Dr. Bryan Robtnfons Treat, of the Anim. CEconomy.

Life ejlates, in our law, are either for the life of the owner, or for the life of another, or others.

Annuity for Life. See the APPENDIX.

Prolongation oi Life. See Prolongation.

LIFTING 'pieces, in a clock, are thofe parts which lilt up and unlock the detents in the clock part.

LIFTS, in a (hip, ropes belonging to the yard arms ot all yards. Their ufe is to flop the yard-arms, ;'. e. to make the end of the yards hang higher or lower, as occafion ferves. The top-fail lifts ferve as Cleats for the top-gallant yards, as well as for lifts to the top-fail yards. The haling of thefe ropes is called topping the lifts : thus they fay Up a ftarboard, or top a port, i. e. hale upon the ftarboard or larboard lift. The lifts for the fprit fail yard, are aWz&Jlanding lifts.

LIGAMENT (Cycl.)— Ligaments of the vertebra. Mr. du Vernoi has mentioned more ligaments of the vertebra; of the back, than are commonly defcribed. See Comment. Acad. Petrop. Tom. VI.

LIGAMENTUM peculiare Jiapides, in anatomy, a name gi- ven by Schelhammer and fome others, to what is properly a mufcle, and is called by Albinusy?«/>«&m, and by Cowper and others mufculus Jlapides mdjfapedaceus.

LIGATURE (t>/.)~ Ligature, ligatura, in the Italian mufic, fignifies a tying or binding together of notes. Hence fyncopes are often called ligatures, becaufe they are made by the ligature of many notes. There is another fort of ligatures for breves, when there are many of thefe on dif- ferent lines, or in different fpaces, to be fung to one fyllable. To underftand this, it muft be obferved, that only breves are capable of this fpecies of ligature, by reafon their figure admits of their being placed fo clofe together, as to feem one character only, though placed on different degrees, unlefs there be occafion to place a femi-circle either above or below them, to (hew that they are tied. This kind of liga- ture regards common time only. Breves again muft be con- fidered as fimple, as having a tail, and as being of different colours. Firft, if they be fimple ji and afcend,- they con- tain their natural quantity, i. e. each two femi-breves. Example A. But if they defcend, then each is equivalent to four femi-breves, if only two follow one another, asinB. If there are three or four following ones, the firft and laft contain each four femi-breves, and thofe in the middle but two, as in C.

2 2 A 2 22 B C

Secondly, if they have tails p, and the tail be turned up- wards, the breves contain only one meafure, as well af- cending as defcending. See Ex. D. But if it be marked downwards, the breve then contains its natural quantity. See Example E. This fpecies of ligature was invented only becaufe the minim being round, could not be ufed in this manner. And the femi-circle was not at that time in ufe. It may be here remarked, that ordinarily the firft breve alone of every ligature has a tail, and that ufually placed on the left fide : laftly, if they be of different colours, /. 1. if the firft be white, or open in the middle, and the fecond black, the firft contains a femi-breve, and the fecond a pointed minim. Example F.

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gEM^fS

11 11 11 11 22 222222

Thefe are the principal ligatures, befides which there are many others, for which fee Nota. Brojfard.

Ligatures, in furgery, called alfo chords, bands, or firings, are of different kinds, fome fine, others coarfe and ftrong, and are made either of flax, or hemp, or cloth, or filk, or horfe hair, according to the nature of the diforder ; for thefe things are almoft conftantly required. We ufe them to re- place or extend bones that are broken or diflocated j to tie the patients down in lithotomy, amputations, and operations of that kind ; to tie up the veins in phlebotomy ; to tie up arteries after amputations, or in large wounds ; to fecure the fplints that are applied to fractures ; to tie up the pro- ceffes of the peritoneum, with the fpermatic veflels in caf- tration ; and laftly, in taking oft" warts, and other excref- cencies by ligature, and in all other operations of this kind. Heijler's Surg. p. 23.

LIGEANCE, ligeantia, is the true and faithful obedience of a fubject to his fovereign ; and is alfo applied to the dominion or territory of the liege lord ; thus children are faid to be born in or out of the ligeance of the king, &V. Stat. 25 Ed. 3. Co. Litt. 129. Terms of Law. Blount, Cozvel.

LIGHT (Cycl. ) — Li g H t from diamonds and other bodies. Light has of late ages become in a manner more common than it ufed to be among us. The chemical phofphori have greatly

increafed its kinds, many electrical bodies are luminous, and many other bodies there are which are luminous with- out being electric.

The antient naturalifts, .and fince their time, feveral other writers, at different periods of time, have been acquaint- ed with many of thefe properties in feveral bodies, though very imperfectly. They have obferved them too carelefsly, often exaggerated them in their accounts, and frequently deftroyed the whole credit of the narration, by a mixture of falfity with the truth. M. du Fay, who laboured extremely in thefe difqui fit ions, has been at the pains of collecting all the accounts of this kind from authors, and feparating truth and probability from what is falfe or abfurd in thefe accounts, has with them given many experiments of his own to the academy of fciences at Paris. Among luminous bodies the diamond is to be reckoned, as fome diamonds are known to fhine in the dark. But on account of the feeblenefs of their fplendor, it is necefiary for the perfon, who is to obferve them, previoufly to ftay in the dark at leaft a quarter of an hour ; that the pupil of the eye may be dilated and enlarged, and fo rendered ca- pable of receiving a larger quantity of the rays of light. M. du Fay has alfo obferved, that the eyes ought to be ihut for this time, or at leaft one of them ; and that, in that cafe, the light of the diamond is afterwards only feen by that eye, which has been fhut. Before the diamond is brought into the dark room, it muft be expofed to the fun fhine, or at leaft to the open day light, to imbibe a fufficient quantity of rays ; and this is done in one minute, or even lefs ; eight or ten feconds having been found to furniih as much light as a ftone is capable of receiving; and when brought into the dark its light continues about twelve or thirteen minutes, weakening all the while by infenfible -degrees. It is Very remarkable, that in bodies fo extremely fnnilar to each other as diamonds are, fome mould have this property of im- bibing the fun's rays and fhining in the dark, and that others fhould not ; yet fo it is found to be by experiment, and the moft nearly refembling {tones {hall be found one to have this property, and another to be deftitute of it ; while the many of the moft diffimilar have this property in common. There feems to be no rule, nor even the leaft traces of any imper- fect rule of judging, which diamonds have and which have not this property j their natural brightnefs, their purity, their fize, or their fhape, contribute nothing to it j and all that has been yet difcovered of the leaft regularity among them, is, that all the yellow diamonds have this property. This may probably arife from their having more fulphur in their compofition, and therefore illuminating more readily, or emitting a more vilible flame.

The burning of diamonds is a term ufed among the jewellers ; for putting them into a fierce fire, as they frequently do, when they are fouled with brown, or yellow, or the like ; this always divefts them of their colour, without doing them the leaft fenfible injury. M. du Fay having been informed of this common pra6tice, formed a conjecture, that tJie difference ot diamonds in their mining, or not mining in the dark, was owing to it ; and that either all thofe which had been burnt, or all thofe that had not, were thofe which alone fhone in the^dark. But this was found an erroneous conjecture ; for two diamonds, one lucid in the dark, the other not, were both burnt, and afterwards both were found to retain the fame properties they had before. It is not only the open fun-fhine, or open &zy-light, which gives to thefe diamonds power of fhining in the dark; they receive it in the fame manner, even if laid under a glafs, or plunged' in water or in milk.

M. du Fay tried whether it was poflible to make the dia- mond retain, for any longer time, the light it naturally parts with fo foon ; and found, that if the diamond, after being expofed to the light, be covered with black wax, itwillihine in the dark, as well fix hours afterwaids as at the time it was firft impregnated with the light. Mem. Acad. Scien. Par. 1735. The imbibing light, in this manner, being fo nice a pro- perty as not to be found in feveral diamonds, it was not to be fuppofed that it would be found in any other ffones : ac- cordingly on trial, the ruby, the fapphire, and the topaz, were found wholly deftitute of it, and among a large num- ber of rough emeralds, one only was found to poflefs it. Such is the ftrange uncertainty of thefe accidents. All the other lefs precious ftones were tried, and found not to poflefs this property of imbibing light, from the day- light, or fun-fhine, but they all became luminous, by the different means of heating, or friction ; with this difference, that fome acquired it by one of thefe methods, and others by the other ; each being unaffected by that which gave the property to the other. The diamond becomes luminous by all thefe ways. Ibid. Light, in the manege. A horfe is faid to be light, in French un cheval leger, that is, a fwift, nimble runner. We Hke- wife call a horfe light that is well made, though he is nei- ther fwift nor active : for in this laft expreffion we confider only the fhape and make of a horfe, without regard to his qualities.

Light upon the hand 5 a horfe is faid to be fuch, that has a

good