place depends on the extent to which these larger groups can dominate the details of the rhythm, and this again depends on the listener's capacity for grasping large and slow rhythms. In any case, the only “ultimate” rhythmic element is the tendency to mark off rhythmic beats into pairs, with a stress on the first of each pair. Where this tendency is resisted, the mind will follow the line of least resistance, which will vary according to the pace and detail of the music. Thus in rapid triple time it is easier to seek duple rhythm in the grouping of bars than in the details within the bars; but if the groups of bars are also triple, or irregular, the mind will fix on the first recurring salient feature for a secondary beat, regardless of inequality in length; rather than, so to speak, hop on one leg indefinitely. On this principle there is a distinct tendency in moderate and slow triple times to throw a secondary accent on the third beat; or sometimes on the second, as in the springing step of the mazurka, where the spring gives energy to the first beat and the descent from it gives poise to the second.
The tendency of small rhythmic groups to build themselves into large and square ones, such as 8-bar, 16-bar and even 32-bar periods, is doubtless important; but the converse tendency of large phrase-rhythms to break up in a tapering series is far more significant, since even in its most regular forms it not only produces more variety the further it goes, but always increases in obvious effect, until the subdivisions attain the minuteness (and therewith the expression) of speech rhythms. (A crude example of the device is Diabelli's waltz, on which Beethoven wrote his gigantic 33 variations. See Variations, where the point is illustrated, by a diagram.) Regularly expanding rhythm, on the other hand, not only becomes imperceptible as it is carried further, but tends merely to make musical proportions resemble those of a chess-board. In great music the expanding principle is therefore always contrasted with or modified by the tapering principle, which can indeed exist simultaneously with it and with any other. For, to take only three categories, the harmonic changes of a passage may be designed in tapering rhythm while the melodic phrases expand, and the entries of instruments or parts occur on some third principle, regular or irregular. Such interplay need produce no feeling of complexity; indeed, it is an art most neglected by those composers who most rely on the effect of complex rhythm. It is the main discoverable source of that almost dramatic sense of movement that distinguishes the great musical styles from the academic methods which play for safety, and from the anti-academic novelties which end in monotony.
Square rhythms become desirable at climaxes where physical energy dominates thought. Strong final cadences accordingly require that the last chord should fall on an accent; and if the pace is rapid the final chord will probably be not only on an accented beat but on an accented bar. Thus it is quite obvious that there is by a mere oversight one bar too many in the four bars of tremolo quavers at the end of the first movement of Beethoven's Fourth Symphony; for they are followed by an important bar leading to the last three chords, which chords can only mean (counting bars as beats)—“One, two, Three” (“four” being silent and therefore unwritten). A fifth bar of tremolo would correct the rhythm in a more vigorous but more vulgar way by bringing the last chord onto “One” of the next imaginary group of four. The former correction is so obviously right that the imagination makes it in spite of the presence of the superfluous bar, which is instinctively ignored as an accidental prolongation of the tremolo. Where the composer writes in bars so short as to be permanently less than the phrases of the piece (as in Beethoven's scherzos), or in bars that are frequently longer than the phrases, (as in most of Mozart's movements in slow or moderate-common time), it sometimes becomes impossible to construe the music without carefully calculating where the accents come; and this calculation is most easily made on the assumption that the strongest cadences bring the tonic chord on an accent. Thus, in Beethoven's Sonata in E flat, Op. 27, No. 1, the first bar of the second movement must be preliminary and the first accent must come on the second bar, sinoe the piece refuses to make sense in any other way. Indeed, Beethoven has written some notes twice over in order to bring his double-bars and repeat-marks where they will indicate the true rhythmic joints to the eye. (A double-bar is a mere graphic indication of some important sectional division, not necessarily rhythmic or even coincident with a normal bar-stroke.)
Theorists, however, have developed a tendency to assume that all cadences must be strong. More than one critic has told us that the scherzo of Beethoven's Sonata, Op. 28, is in the same predicament as that of Op. 27, No. 1; though it not only makes excellent sense with its cadences in the light and weak form in which they appear, but, when re construed on the “strong cadence” theory, entirely fails in its middle portion to uphold that theory or to make any other rhythmic sense. And when Professor Prout tells us that the overture to Figaro begins with a silent bar, and that Schubert's Impromptu in B flat is positively ungrammatical in its cadences unless it is entirely rebarred, and when Dr Riemann turns half the ritornello of a Bach concerto from 44 into 32 time, simply in order to make the sequences coincide with the hardest possible accents; then we can only protest that this is regulating musical aesthetics by criteria too crude for the aesthetics of bricklaying. An edition of Paradise Lost, in which the lines were so rearranged as to bring all punctuation marks (except perhaps commas) at the end of the line, would be on precisely the same level of ingenious barbarity.
Few technical terms are entirely peculiar to the subject of musical rhythm; but some obvious terms of syntax, such as phrase, period and section are used with varying degrees of system by all writers on music; and the whole terminology of prosody has been annexed—with such success that we are told in Grove's Dictionary, (article “Metre”) that “the theme of Weber's Rondo brillante in E flat (Op. 62) is in Anapaestic Tetrameter Brachycatalectic, very rigidly maintained.”
One important term has acquired a special significance in music: viz. Syncopation. It means a cross-accent of such strength as to equal or even suppress the main accent; but the use of the term is generally restricted to cases in which the cross-accent is produced by shifting the notes of a melody or a formula so that they fall between the beats instead of upon them. From what we have said as to the almost physical energy of musical rhythm it is obvious that such a phenomenon is of far greater effect and importance in music than it could possibly he in verse; and, to whichever subject the term may belong by priority, extreme caution is needed in extending any musical notion of it to the structure of poetry. (D. F. T.)
RHYTINA, a name applied to the northern sea-cow (Rhytina gigas, or stelleri), a gigantic relative of the manati and dugong, which formerly inhabited Bering and Copper Islands, in the North Pacific, where it was discovered during Bering's voyage in 1741, and subsequently described by Steller, who accompanied that expedition as a naturalist. Bering's half-starved sailors soon reduced the numbers of these comparatively helpless creatures; and it was not long after—probably about the year 1768—that the species, which was the sole representative of its genus, became completely exterminated. The Rhytina was the largest member of the order Sirenia, attaining a length of nearly twenty feet; and had a very thick, rugged, bark-like skin. The jaws, which are bent downwards to a moderate extent, are unprovided with teeth, but in life carried ridged horny plates. The tail was very deeply forked; and the flippers were short and truncated, lacking apparently the terminal joints of the digits.
When first discovered, this Sirenian was extremely numerous in the bays of Bering Island, where it browsed upon the abundant sea-tangle. Its extirpation is due to the Russian sailors and traders who visited the island in pursuit of seals and sea-otters, and who subsisted on its flesh. Numbers of bones have been discovered in the soil of Bering and Copper Islands, from which more or less nearly perfect skeletons have been reconstructed, so that the osteology of this interesting animal is well represented in most of the larger museums. (R. L.*)
