T l 



J.vi 



T T 



tetrachoru other modi-*, the Dorian*. 



-.' which v 



iag to him, thi '. 

 octave, so'mewh 



&idca has Ucn started of 

 s, or rather answering to diner- 

 -.HIT intermediate 



bemitoncs iiist. .id of some ol I! it would In- difli- 



AC tliiuk, to produce, authority enough for thi* con- 

 jecture. 



If it were true, as supposed, that the two octaves of the 

 Greek scale, beginning, say with A, were minor, it would 



.ionic scales, exhibited the 

 .1.1 we ha\e supposed. According!/, 



the ]iriiiei]ial mode of exhibiting the formation of the 

 oetu\e from two tetrnchords and a tone would be ihe one 

 i\e taken, namely, 



D B F) (G A B C 1 ) 

 But it is frequently .supposed that it was the following : 



K V ( G } A B C ) 

 or the following 



A{BCD(E}FGA). 

 On this point we shall only say that there never was, 

 we believe, so strong a union of the three chancten of 

 scholar, mathematician, and musieian. ' in Dr. 



Smith, the author of the Harmonics. He had studied the 

 :!< attentixely, and to him the first of these me- 

 thods was a matter of course. 'The Greek musicians' 

 monies, 171'.', ]' -I"' , ' alter dividing an octave into 

 n the diazeuctie or major tone in thi- middle 

 in. and admitting many primes to the composi- 

 tion of musical ratios, subdivided the fourth into three in- 

 tervals of various magnitudes placed in various order*, by 

 which they distinguished their kinds of tetrachords.' 



\Ve do not, we confess, though admitting that it is ex- 

 ceedingly hard, and probably impossible, to reconcile the 

 , w'riter* with themselves and each other, find that 

 sort of difficulty which Dr. Burney owned to, when he said 

 that he neither understood those writers himself, nor had 

 met with any one who did. He was a musician, and was 

 looking out ibr an intelligible mode of arriving at and dis- 

 tributing the most agreeable concords, with a strong pre- 

 determination to arrive at musical truth or nothing. But 

 the Greek writers were arithmeticians, with as strong a 

 filiation to find natural foundations in integer num- 

 they did nut ask how to iiiul sounds which would best 

 suit the ear, but bow ti> discover trij tious which 



multiplied together should produce four-thirds of a unit. 

 Pleased with the .simplicity of the ratios which give the 

 fourth, fifth, and octaM , ih>-ii- efforts at musical improve- 

 ment were confined to the attempt at discovering magic 

 numbers to fill up theintenals. It was not until one of 

 these philosophers had laboured at his abacus, and tasked 

 his metaphysics to find a prinri confirmation of some 

 question in arithmetic, that he strung his monochord and 

 tried how his scale sounded: it would have been hard 

 indeed if his ear had refused to sympathize with his brain. 

 In all probability the musicians, whose object was simply 

 to please, laughed at the arithmeticians, as Tycho Brahfe 

 did . -Alien the latter had discovered reason for 



the of the planets in the properties of solid 



bodies: they had motive enough, and, beyond all question, 

 reason more than enough. 



i K.VHOKI) T,TfMTtaftor, ' four-stringed'), in the 

 music of the Greeks, was a system of four sounds, as, for 

 example, the diatonic tetrachord, c, D, K, K : the chromatic, 

 K; and the enharmonic, c. i ;. u b, F. The 

 antienU proceeded from the key-note to the octasc by two 

 conjoint tetrachords; and so far as the diatonic scale is 

 concerned, they and the moderns agree. In what relates 

 to the two other scales, so little * accurately known, and 

 the subject is so unimportant, to either the general or the 

 musical reader, that we should not further enter on it, 

 if the. (space allotted to our department alluv 



[GK\EH\ : Mi sir. HISTORY or.] 



TETRADY'NAMOUa from rirrajwc, /';.'/, and r.Vn/uc, 

 fOWtT), a botanical term emploved by Lii indicate 



thi' chmaetct ot those flowers which, possessing six stamens, 

 have two of them shorter than the other four. This pecu- 

 liarity is found exclusively in the plants belonging to the 



natural order Crucifene, Hence the Lmnean class Tetrady- 



uamia, including only plant* with the stamens arranged in 

 tin.- manner, is an < \ . and is one of 



the few in-tances in which a p. in the stamens 



prevails throughout a whole family. Ifiilytmiiiout is the 

 term which expresses Ihe i two 



of which are short and two long. This ch. 



' number of natural families, as Ijii ph.!- 



lariaceai, Bignoniao :.d i-> ai .ilent 



throughout a family where ! class 



Didvnamia is Umndcd Oil this peculiarity ol 



, rly a four-angled ! '.-mi 



usually applied to the square only, when used, which it 

 seldom 



TFTK.UJt )N I i natural order of plants. ] 



by Liudlcy HI his llui \cmbryose group of incomplete Dico- 

 tyledons. It includes the genera Tetragonia, Aizoon. Se- 

 suvium, and Miltns. which an geneiallx placed in the 

 order Ficoidese or Mesembryacese. The reason gi\eo by 

 Dr. Lindley for this separation is the want of pet:. 

 these genera, as he considers that the tendency to produce 

 petals in the Mesembryaccas is of too powerful a nati 

 admit exception. The relation of thci-c api-i.ilous Ficoi- 

 dea- to Chenopodiacew is so stronir, that Dr. l.niilU 



is no character to distinguish them, except their 

 ovary being formed of several carpels.' 



Like Ficoidese, this order possesses thick Micenient 

 leaves, which in many of the specie., might be used as a 

 substitute for spinach. The '/ is a 



native of New Zealand and Japan, and is used by the 

 natives of those countries as a remedy in tho- 

 cutaneous disease called scorbutic. It might be used in 

 cookery instead of spinach. The Aizoon MMTtMM and 

 A. hispanicum grow on the sea-coasts of the Canary Isles 

 and Spain, and are amongst the plants which yield soda 

 after burning. 



TETRAGON O'LOBUS (from rfrrapif.four, yvla,a>ifrl<; 

 and \6Sof, lobe}, a genus of plants belonging to the papilio- 

 naceous division of the natural order Letruminos;e. It con- 

 tains herbs with broad lea IV stipules, tri foliate lea vt-s. winged 

 petioles, alternate leaflets and flowers seated on axilla 

 duncles, furnished wit ha brail. The cah x is tubular 5-cleft, 

 the wings shorter than the vexillnm : the stiirma is funnel- 

 shaped and beaked : the legume is cylindrical, furnished 

 with four foliaceous wings, which give it a 4-cornered ap- 

 pearance. 



T. furjiureut ("purple winged-pea) is a pilose plant with 

 decumbent stems, entire obovate leaflets, bracts longer 

 than the calyx, and a glabrous leirume. with globose - 

 It is a native of the south of Europe, and has dark purple 

 flowers; a variety is, however, found with flowers of a 

 dark yellow colour. 



There is also a variety called T. p. minor, in which the 

 stem, leaves, and legumes are much smaller. In southern 

 rcirions. where this plant -rrows in perfection, the unripe 

 letrumes are cooked and eaten in the same manner as we 

 MU French beans. 



There are four other species of Tetrsgonolobus, all of 



them inhabitants of Europe. In gem-nil appearance they 



very much resemble the species of Bird's-foot trefoil 



Lo'tusl. and in gardens are well adapted for ornamenting 



rock-work. They are best propagated by s- 



TETRAHEDRON i ft solid of lour faces . a term usually 

 applied to fhe regular tetrahedron, f KK(;I I.AH Pl)VMS.1 



TETRAD. [Turn U.MO.K.] 



TKTI;.\IK;.\ I.I.I S. Mr. ,}. K. Grny's nnme for a ceniis 

 of birds, placed by Mr. G. K. (lr:i\ in the subfamily /."/-A</- 

 :,r. of the 'family 1'h'miniiiilir. Example, '/' 



'///. (Ill.Ind.7L 



TKTKAO'M !).!:. Dr. Leach's name for the Grouse 

 family. 



Linneus, in his last edition of the N//- 'ra>, 



- the genus Tflrno at the end of his fiHh order, 



next to the genus .\iiiniiln. The Hnllina* come 

 between the (im/lrr- and the 1'astrrrt : th> -thin 



is the laM of the order Urullff, and th. ,/mba 



the first of the order Patserei. 



The Linnean genus Trl, \t.-n-i\e. comprising 



not only the true Grouse, but also the Fraucolins. 

 t ridges, and Quails. 



('in in. in Ins last edition of 11 <--/i'//m/, urr;i. 



the '/'. -mi. under his fomth order. ' 



nacte ((jaltin<e, Linn.;, placinj; them between the Phea- 



