6.  Mus.taf.’ilun, for ’I.lun.mafa, i.e. two Sabab khafif, followed by Watad majmu’ = the Latin Epitritus tertius (- -U-), or: 

7.  Fa.’ila.tun, for Lun.mafa.’i, i.e.  Watad majmu’ between two Sabab khafif = the Latin Epitritus secundus (-U- -).

8.  Mutafa.’ilun (for ’Alatun.mufa, the reversed Mufa.’alatun), i.e.  Fasilah followed by Watad majmu’=the Latin Anapaest succeeded by Iambus (UU-U-).  The last two secondary feet are transpositions of No. 4, Fa’i.la.tun, namely: 

9.  Maf.’u.latu, for La.tun.fa’i, i.e. two Sabab khafif, followed by Watad mafruk = the Latin Epitritus quartus (- — -U).

10.  Mus.taf’i.lun, for Tun.fa’i.la, i.e.  Watad mafruk between two Sabab khafif=the Latin Epitritus tertius (- -U-).[FN#452]

The “branch"-foot Fa.’ilun (No. 5), like its “root” Fa’u.lun (No. 1), is quinqueliteral.  All other feet, primary or secondary, consist necessarily of seven letters, as they contain a triliteral Watad (see supra i. 2) with either two biliteral Sabab khafif (i. 1) or a quadriliteral Fasilah (i. 3).  They are, therefore, called Saba’i = seven lettered.

iii.  The same principle of the Watad taking precedence over Sabab and Fasilah, rules the arrangement of the Arabic metres, which are divided into five circles (Dawair, pl. of Dairah), so called for reasons presently to be explained.  The first is named: 

A. Dairat al-Mukhtalif, circle of “the varied” metre, because it is composed of feet of various length, the five-lettered Fa’ulun (supra ii. 1) and the seven-lettered Mafa’ilun (ii. 2) with their secondaries Fa’ilun, Mustaf.’ilun and Fa.’ilatun (ii. 5-7), and it comprises three Buhur or metres (pi. of Bahr, sea), the Tawil, Madid and Basit.

   1.  Al-Tawil, consisting of twice

     Fa’u.lun Mafa.’ilun Fa’u.lun Mafa.’ilun,

the classical scheme for which would be

U - - | U - - - | U - - | U - - - |

If we transfer the Watad Fa’u from the beginning of the line to the end, it would read: 

Lun.mafa’i Lun.fa’u Lun.mafa’i Lun.fa’u which, after the substitutions indicated above (ii. 7 and 5), becomes: 

   2.  Al-Madid, consisting of twice

     Fa.’ilatun Fa.’ilun Fa.’ilatun Fa.’ilun.

which may be represented by the classical scheme

- U - - | - U - | - U - - | - U - |

If again, returning to the Tawil, we make the break after the Watad of the second foot we obtain the line: 

     ’Ilun.fa’u.  Lum.mafa ’Ilun.fa’u Lun.mafa, and as metrically

’Ilun.fa’u (two Sabab followed by Watad) and Lun.mafa (one Sabab followed by Watad) are=’Ilun.mafa and Lun.fa’u respectively, their Taf’il is effected by the same substitutions as in ii. 5 and 6, and they become: 

   3.  Basit, consisting of twice

     Mustaf.’ilun Fa.’ilun Mustaf.’ilun Fa.’ilun,