The metres were called Buhur or “seas” (plur. of Bahr), also meaning the space within the tent-walls, the equivoque alluding to pearls and other treasures of the deep.  Al-Khalil, the systematiser, found in general use only five Dairah (circles, classes or groups of metre); and he characterised the harmonious and stately measures, all built upon the original Rajaz, as Al-Tawil (the long),[FN#438] Al-Kamil (the complete), Al-Wafir (the copious), Al-Basit (the extended) and Al-Khafif (the light).[FN#439] These embrace all the Mu’allakat and the Hamasah, the great Anthology of Abu Tammam; but the crave for variety and the extension of foreign intercourse had multiplied wants and Al-Khalil deduced from the original five Dairah, fifteen, to which Al-Akhfash (ob.  A.D. 830) added a sixteenth, Al-Khabab.  The Persians extended the number to nineteen:  the first four were peculiarly Arab; the fourteenth, the fifteenth and seventeenth peculiarly Persian and all the rest were Arab and Persian.[FN#440]

Arabic metre so far resembles that of Greece and Rome that the value of syllables depends upon the “quantity” or position of their consonants, not upon accent as in English and the Neo-Latin tongues.  Al-Khalil was doubtless familiar with the classic prosody of Europe, but he rejected it as unsuited to the genius of Arabic and like a true Eastern Gelehrte he adopted a process devised by himself.  Instead of scansion by pyrrhics and spondees, iambs and trochees, anapaests and similar simplifications he invented a system of weights ("wuzun").  Of these there are nine[FN#441] memorial words used as quantitive signs, all built upon the root “fa’l” which has rendered such notable service to Arabic and Hebrew[FN#442] grammar and varying from the simple “fa’al,” in Persian “fa’ul” (U _), to the complicated “Mutafa’ilun"(UU — U -) , anapaest + iamb.  Thus the prosodist would scan the Shahnameh of Firdausi as

               Fa’ulun, fa’ulun, fa’ulun, fa’al. 
                U — — U — — U — — —

These weights also show another peculiarity of Arabic verse.  In English we have few if any spondees:  the Arabic contains about three longs to one short; hence its gravity, stateliness and dignity.  But these longs again are peculiar, and sometimes strike the European ear as shorts, thus adding a difficulty for those who would represent Oriental metres by western feet, ictus and accent.  German Arabists can register an occasional success in such attempts:  Englishmen none.  My late friend Professor Palmer of Cambridge tried the tour de force of dancing on one leg instead of two and notably failed:  Mr. Lyall also strove to imitate Arabic metre and produced only prose bewitched.[FN#443] Mr. Payne appears to me to have wasted trouble in “observing the exterior form of the stanza, the movement of the rhyme and (as far as possible) the identity in number of the syllables composing the beits.”  There is only one part of his admirable version concerning which I have heard competent readers complain; and that is the metrical, because here and there it sounds strange to their ears.