Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/617

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in large white irregular lumps, when held to the fire it emits copious fumes findfing ltrongly of garlick and fulphur, but it does not readily melt or run.

TELE1NA, in natural hiftbry, a fea-fhell, by the lateft writers on thcfe iubjects, referred to the genus of mufcles. See the article Mytulus.

Theie (hell-fifh do not naturally live on the furface of the bottom of the fea, but bury themfclves in the mud or fand, in the manner of the chamae, keeping a communication with the water above by means of the fame fort of tubes or pipes as thole filh are puffeiled of; but as the tubes of the Tellina are very lhort, the filh can only bear to be buried to a fmall depth.

W ben the water covers the bottom where they lie, they re- main always buried in the fand ; but when the fea in its ebb leaves the place dry, they very often come out of their holes, and arc feen lying fiat upon their fides on the fand ; whether this be to take in irelh air, or, which feems more probable, to ieek after the water which has abandoned them. They fecm alfo to go far in fearch of it, for it is common to fee them at a toot uurauce from their hole, with the furrow marked by their progreliion all the way behind them, from the aperture ot their celi to the place where they are found. They perform this motion by means of a fort of foot, fuch as the cbamie, the lourdon, a.U many other bivalve lhells have ; but the leg to which tins toot is fattened, is in this fpccies very lhort, and not capable ol any great exteniion. Mem. Acad. Par. 1 7 1 0.

TELON, a name given by the chemifls to fire.

1 ELONiE, tixSks., among the Athenians, farmers of the pub- lic revenues ; tor the feventy with which they were handled, in cafe they failed, fee Potter Archieol. Gnec. 1. 1 c. li. T. I. p.b'i. T

TEL 1 NO, a name given to the Urogalks, or great cock of the mountain. See 1 ab. ot Birds, N°. 25. and the article Uro- GALLUS.

I EEONIUM, among the Romans, is ufed to denote a cuftom- houie, or place where the toll was collected. See Pitifc. in voc. and Thelonium, Cyel.

1 EM, or brown Tim, in zoology, the name of a water-fowl ot the larus or gull-kind, calleu oy Aldrovand Larus cincreus minor.

It is but a fmall fpecies. Its back and wings are of a pale grey, with fome faint admixture of bluiill; and the longer leathers of the win 6 s are black within. The beak is very fmall, fomewhat crooked, and black. The back part of its head alio is black. All other parts of the body are of a fine white. The feet are webbed, and the legs arc yellow. Rat\ Ornithol. p. 268.

TEMACHIS, in natural hiflory, the name of a genus of fulfils, of the clafs of the gypfums ; the characters of which are thefe. It is of a fotter fubffcance than many of the other genera, and vi a very bright and glittering hue.

I he name is derived from the Greek -n^x'\ frujtulum, a fmall irregular fragment ; the bodies of this genus being ■computed of an allemblage of multitudes of irregular flaky fragments, as are all the gypfums ; but no genus of them fo vjhbly lb as thefe.

1 here are but three known fpccies of this genus : 1. A foft Ihining green one. 2. A foft white one, of a marbly ap- pearance. And, 3. A pale brown gloffy one. The firll is found in great plenty on the fhores of rivers in the Eaft-In- dies ; and though not known as a fubftance that would make a plaiter by burning, is given internally in nephritic cafes, being powdered without calcination. 'I 'he fecond is found in many parts of Derbyshire, and is ufed for burning into plaftcr for Ituccoing of rooms, anil calling ftatues, &c. And the third is found in Germany j and, befide its common ufes in ftuccoing and calling, is in great efteem among the metal- Jurgilts and afiiiycrs, for the making either lingly or in mix- ture with bone-afhes, their tefts. See the article Test. We have not this fpccies in England (a far as is yet known. H'U's Hift. of FofT. p. 113, 114, 115, 116.

TEMAPARA, in zoology, the name of a peculiar fpecies of lizard, called alio Tejuguaeu.

It approaches much to the nature of the Iguana, but is black fpotted with white. See the articles Iguana, and Teju-

GUACU.

TJ'.MBUL, in botany, a name ufed by fome authors, for the plant called betlc, an herb the people of the Eait-lndies are tond of chewing. C. Baubin. pin. p. 410. See the article

fiETLE.

TEMELO, in zoology, a name ufed by fome for the filh cal- led in Enghfh the greyling, and in fome places the umber. It is a truttaceous fpecies, known among the writers in ich- thyography under the name of Tbymallus. IVillugbby's Hill. Pile. p. 187. See the article Thymallus.

TEMPATLAHOAC, in zoology, the name of a broad-billed bird, of the Welt-Indies, defcribed by Nieremberg ; and by him efteemed a fpccies of duck.

It is of the fize of the common duck. Its head and neck are green, black and purple, and very bright and mining like the neck of the peacock. The body is of a brownilh yellow, and it has two large fpots of white on each fide near the tail. The tail is white all round the edges, and is of the fame Suppl. Vol. II.

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marks and colours with the peacock's, but black underneath, it is common on the lakes of Mexico, and is a good eatable bird. Ray's Ornithol. p. 299. TEMPERAMENT, or Temperature, [Cycl.) in mufic. Mr. Chambers, under this head, informs us, that the Tempera, went, or Temperature, denotes a rectifying or mending falfe and imperfeft concords, by transferring to them part of the beauty of the perfedt ones. This he took from Mr. de Fon- tcnelles, in the Hift. de l'Acad. ties feiences, J701. But this requires a fuller explanation ; for though it be true, confidered iu one light, that a Temperature coirefls fome falfe concords ; yet it is no lefs true, that, in other refpedfs, it fpoils and faliifies both perfefl and imperfefl concords, and renders difcords more harfh than they would otherwife be, if the intervals vere juftly taken. To explain this, we mult coniider that all the intervals are founded on the primary pro- portions anting from the numbeis 2, 3 and 5, that is, if we do not exceed the compafs of an oftave, {, \ and ?. See the article Interval.

The nearer we come in praSice to the true intervals, the more perleit the melody and harmony will be ; and it is cer- tain, that the human voice, and fome inurements, as violins, c?r. which have no Hops nor frets, will execute mufic to a great degree of eXS£tae6 ; but the cafe is not the fame with fixed or fretted inltruments, as harpfichords, organs, lutes, viols, tic. Accuracy is here impoffible, unlefs we would content ourfelves with always playing in the fame key, with- out any tranfition or tranfpofition whatfoever. In this cafe, indeed, the harpfichord or organ might vie with the accuracy ol the voice or violin. For inftancc; if we were to compofe or play in the key of C, then we might make the feveral in- tervals of that key, to be in the following true proportions,

E. F. G. A B C 24 ' 27
 * ■ i ■ •'," ■ 51 .!,•¥•{. -If that is in whole numbers C ' D '

manner, would perform any piece of mufic in C, juftlv com- pofed, with great beauty and exactnefs, I here take for granted, that every key, fundamental note, or found, ought to have its true fifth and fourth, and that thefe ought alfo to have their true fifths and thirds.
 * 3° • 32 . 16 . 4.0 4.C 4,8 ant * l ^ e " 1 ^ rument ' tuned in this

Now this being prcmifed, it will prefently appear, that in making any tranfpofition or tranfition from C, we mall find fome falfe concord. Thus, for inftance, if we proceed to G, and confider it as a key, or fundamental found, we (hall have the following feries of numbers for the o£tave of G, viz G . A . B . C . D . E . F . g

36 . 40 . 45 . 48 . 54 . 60 . 64 . 72. But here the interval between 40 and 54 is falfe, being a comma too much, for the fecond of a key muft make a true filth with the fifth of the fame key. In like manner, if we were to proceed from C to A, as a new key, we fhould find the following feries for the

odlaveofA, „, , where the

■ 40 . 45 . 48 . 54 . 60 . 64 . 72 . 80, interval between A 40 and its fourth D 54 is falfe, being too great by a comma. If any other tranfition were examined, we fhall always find fome note falfe ; as in F, the fixth would be redundant by a comma. And in D the fifth would be de-. ficient by a comma. All which (hews the impoflibility of truth and exa&nefs of mufic on fixed inftruments. Yet as thefe inftruments have their ufe and convenience in fome re- fpefts, it was proper to endeavour to find out a method of making them tolerable.

It has been obferved under the head Interval, that the tone major exceeds the tone minor by a comma. Their dif- ference is neceflary for the truth and perfection of mufic; but yet if thefe tones were rendered equal, the ear would not be offended. And this has fuggefted the means of tempering fixed inftruments. If we were to make alt tones equal to the tone major, as fome imagine the antientsdid, then we fhould find the ditonus or third, exceeding a true third major by one comma, which would be intolerable. In like manner, if all tones were to be minor, we fhould have thirds major de- fective by a comma, which would alfo be intolerable, not to mention other falfe intervals that muft neceflarily arife from fuch a fuppofition.

Suppofing then one tone increafed, and the others diminifhed by half a comma, we fhould have our thirds major remain perfect. But ftill it would be neceffary to examine what fifths this fuppofition would give. Now it is evident that a tone major added to an octave, makes juft too fifths, thus

jor, and the tone we have afTumed is a temperate tone, defi- cient from the tone major by half a comma; hence the fum of the two fifths, on this fuppofition, will fall fhort of the truth by T of a comma, and confequently one fifth will be de- ficient by \ of a comma. Which difference, although it be fenfible, yet experience fhews, that fifths fo diminifhed are tolerable.
 * X £ — t — 5 X t. But the tone here added is a tone ma-

This Temperature is what is called the common or vulgar Tem- perature, and confifts, as has been faid, in diminifhing the fifth by 4 of a comma, in preferving the third major perfect, and dividing it into two equal tones. Which being fuppofed, it follows thai the fourth muft exceed the truth by \ of a com- ' Eeee ma 5