Page:Cyclopaedia, Chambers - Volume 2.djvu/707

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of Mulic, viz. the fixing and limiting the Sounds j We fee the Realbn why the Names ot the Natural Scale are continued,* only making a Distinction of each into a Greater and Lefs. Thus an Interval of one Semi-tone is called a Lejjer Second - 7 of two Semi-tones, a Greater Se- cond} of three Semi-tones, a Lefs Third ; of four, a Greater Third, &c.

A fecond Kind of Semi tonic -Scale we have from ano- ther Divifion of the Octave into Semi-tones ; which is performed by taking an Harmonical Mean between the Extremes of the Greater and Zefs Tone of the Natural Scale, which divides it into two Semi-tones nearly equal : Thus the Greater Tone 8 : 9 is divided into 16 : 17) and 17 : 18 ■-, where 17 is an Arithmetical Divifion, the Numbers reprefenting the Lengths of Chords ^ but if they reprefent the Vibrations, the Lengths of the Chords are reciprocal, viz. As 1 : 16 • -J, which puts the Greater Semi-tone i^ next the lower Part of the Tone, and the Letter *| next the Upper, which is the Property of the Harmonical Divifion. After the fame Manner the Lejjer Totzc 9 : 10 is divided into the two Semi-tones 18 : 19 and 19 : 20, and the whole Octave ftands thus :

c.ct.d.d$.e.f.f$.g.g.%. a. b. b .c

This Scale, Mr. Salmon tells us, in the 'Philofopb. Tranfatl. he made an Experiment of, before the Royal Society, on Chords, exactly in thefe Proportions, which yielded a perfect Contort with other Inftruments, touch'd by the belt. Hands. Mr. Malcolm adds, That having calculated the Ratios thereof, for his own Satisfaction, he found more of them falfe than in the preceding Scale 5 but their Errors were considerably lets, which made Amends.

SEMINAL, in Medicine, &c- Spermatic, or forne- thing belonging to the Semen or Seed. See Seed.

SEMINALIS CAPSULA, or Seed-Sag, is the Husk, that contains the Seed of any Plant.

SEMINALES VeficuU. See Vesiculje Semijiales.

SEMINAL Leaves : Much the greateft Part of all Seeds, lbwn in the Earth, come up, or /hoot forth at firft with little, plain, ibfr, and undivided Leaves j which, becaufe they are ufually very different from the Leaves of the Succeeding Plant in Magnitude, Figure, Surface, andPofition, are called Seminal Leaves : As the little embrionated Plant, which lies in Miniature in every Seed, is called the 'Flantttla Seminalis. See Plant and Leaf.

SEMINARY, a Place appointed for the Inftrucf ion of young Perfons, defined for the Sacred Miniftry, in the Duties, Ceremonies, and Offices thereof ; firft. inftituted, as Tkomafm tells us, by St. Augufin. Of thefe Semi- naries there are many abroad, furnifh'd with Halls for the AtTemblies of the Exercitants, and little Chambers, or Cells, where each Perfbn retires, ftudies, and prays apart: Such is the Seminary of St. Sulpitius at 'Paris. The Council of Trent decrees, That Children exceed- ing 12 Years of Age, be taken, brought up, and in- ftru&ed in common, to qualify them for the Ecclefiafti- cal State j and that there be a Seminary of fuch belonging to each Cathedral, under the Direction ot the Bifnop. In France, the Eftablifhment of Seminaries is fomewhat different from the Decree of the Council. None are taken in but young People ready to ftudy Theology, and be ordained : So that the Seminaries are a Kind of Houfes of Probation, where the Vocation of Clerks is examined, and they prepared to receive Orders. For the Subfiftance of thefe Seminaries, there are feveral Uni- ons of Benefices, or elfe the Clergy & the Diocefe are obliged to contribute to maintain them. Pope 'iPius IV. having eftablifhed a Seminary at Rome, in Confequence of the Decree of the Council of Trent ; by Advice of the Cardinals, it was given to the Jeliiits, who have made

good Ufe thereof Among the Canons of S. Azigttfline,

Seminary is ufed for a Kind of College, or School, where Penfionaries are kept, and inftrucfed in the Claflical and other Learning.

The Houfes of the Society ■ de propaganda Fide, efta- blifhed for the preparing of Eccleliafficks for Miffio- ons among Infidels and Hereticks, are alio called Semi- naries : The Principal whereof is that at Rome, called, The- Apoplical College, Apoplical Seminary, <Papral Seminary, Seminary of the Propaganda, &c.

SEMINATION, in Natural Hiflory, £#r. the Aft of fowing or fhedding Seed j particularly, that of Vegeta- bles. See Seed-

Affoon as the Seed is ripe, Dr. Grew obferves, Na- ture takes feveral- Methods for its being duly S<Wn:

Not only by the Opening of the Uterus, but in the Make of the Seed it felt. Thus, the Seeds of many Plants, which affect, a peculiar Soil or Seat, as Arum y Poppy, &c. are heavy and fmall enough, without farther Care, to fall directly down to the Ground. Others, that are large, and light enough to be expofed to the Wind, are orten furnifhed with one or more Hooks to ftay them from Graying too far from their proper Place : Thus, the Seeds of Avens have a lingle Hook j thole ot Agrimony and Gcoie-grafs, many; both the former loving a warm Bankj and the laft a Hedge for its Sup. port. On the contrary, many Seeds are turnifhed with Wings, or Feathers 5 partly with the Help of the Wind to carry therm when ripe; off the Plant, as thoie of Afh, ^c and partly, to enable them to make their Flight more or leis abroad, that they may not, by fal- ling together, come up too thick ; and, that if one fhould mils a good Soil or Bed, another may hit. So the Kernels of Pmes have Wings, though fhort ones, where, by they don't fly in the Air, but only flutter on the Ground. But thole of Typha, Dandelion, and moil of the pappous Kind, have numerous long Feathers, by which they are wafted every Way. Others are fbwn by being laid in fpringy elaftic Cales, which, when they crack and burft, dart their Seed at convenient Diftances; Thus, Wood- Sorrel having a running Root, Nature fees fit to low the Seed at fbme Diftance, the doing of which is effected by a white, iturdy, tendinous Cover, which beginning to dry, burfts open on one Side in an Inflant, and is violently turn'd Infide outwards. The Seed of Harts-tongue, and codded Arlmart, is flung, or fhot away by means of a Spring, wound, or girt round the Seed- cafe. When the Spring is become ftark and tenfe enough^ it iiiddenly breaks the Cafe into two Halves, like little Cups, and fo flings the Seed.

Other notable Means of Semination are obferved by other Authors : A Quantity of Fern-Seed, Mr. Ray tells us, laid in a Lump, on a Paper, the Seminal Veficulee are heard to crackle, burft, and, by a Microfcope, the Seeds are feen to be projected to a considerable Diftance from each other. Dr. Sloane obferves, That the Gentia- nelia flore Cozruleo, or Spirit Leaf, requiring wet Wea- ther to be fown in, affoon as the leaft Drop of Rain touches the End of the Seed-Veflels, with a fmart Noife, and a fudden Leap, it opens it felf, and, with a Spring, fcatters its Seed. The Plants of the Card ami ne-Family, throw their Cods open, and dart out their Seed upon a flight Touch of the Hand. Nay, Mr. Ray adds, That the Pods of the Cardamine Impatims not only burft upon the flighteft Touch, but even by an Approach of the

Hand to touch them, without any real Contacf. •

Other Plants fbw their Seeds by inviting Birds, by their agreeable Tafte and Smell, to feed of them, fwal- low them, and carry them about 5 thereby alio ferti- lizing them, by palling through their Bodies. In fuch Manner are Nutmegs, and MifTeltoe, fown and propa- gated. See Nutmeg and Misseltoe.

SEM1TA LUM1NOSA, is a Name given to a Kind of Lucid Tra£t in the Heavens, which, a little before the Vernal Equinox, may be feen about Six a Clock at Night, extending from the Weftern Edge of the Hori- zon, up towards the Pleiades. The Phenomenon hath been taken Notice of by Caffmi and Fatio, who both evince, That this Light comes diffufed from both Sides of the Sun : Its Brightnels is much the fame with that of the Via Laclea, or the Tail of a Comet : It is feen plaineft with us about the Beginning of October, or the latter End of February. Fatio conjectures, That the Bo- dies, or rather the Congeries or Aggregate of thofe Bo- dies, which occafion a Light, doth conform to the Sun like a Lens, and takes it to have ever been the fame ; but, Caffmi thinks it arifes from a vaft Number of fmall Planets, which encompafs the Sun, and give this Light by Reflexion, efteeming it alfo not to have exifted long before he obferved it.

SENA, or Senna, in Medicine, a purgative Leaf, much ufed in Compofitions of that Kind: The Shrub which bears it, is cultivated in feveral Parts of the Le- vant, and grows five or fix Foot high. It puts forth woody Branches, furnilhed with Leaves on one Side : Its Flowers are yellow, and yield a Fruit in Manner of a greenifh flat Pod, containing feveral Lodges or Cells of Seeds, refembling Grape-ftones. Theft Pods fome Phyli- cians prefer to the Leaves themfelves. There is alfo a Kind of Sena cultivated about Florence, but 'tis inferior to that of the Levant, as is owned by the Ltalians them- felves. Father 'Flumier mentions a Third Kind growing in the Antilles Iflands. M.Lemery diftinguifhcs three Kinds of Sena of the Levant, The firft brought from Seyda^ called Sena of Appalto, that is Cnftom Sena, by reafon of the Cuftom paid the Grand Seignior, for the Privilege

of