Now with regard to the Hashw on the one hand, and the ’Aruz and Zarb on the other, the changes which the normal feet undergo are of two kinds: Zuháf (deviation) and ’Illah (defect). Zuháf applies, as a rule, occasionally and optionally to the second letter of a Sabab in those feet which compose the Hashw or body- part of a verse, making a long syllable short by suppressing its quiescent final, or contracting two short quantities in a long one, by rendering quiescent a moved letter which stands second in a Sabab sakíl. In Mustaf’ilun (ii. 6. = - - U -), for instance, the s of the first syllable, or the f of the second, or both may be dropped and it will become accordingly Mutaf’ilun, by substitution Mafá’ilun (U - U -), or Musta’ilun, by substitution, Mufta’ilun (- U U -), or Muta’ilun, by substitution Fa’ilatun (U U U -).[FN#454] This means that wherever the foot Mustaf.’ilun occurs in the Hashw of a poem, we can represent it by the scheme U U U - i.e. the Epitritus tertius can, by poetical licence, change into Diiambus, Choriambus or Paeon quartus. In Mufá’alatun (ii. 3. = U - U U -) and Mutafá’ilun (ii. 8. = U U - U -), again, the Sabab ’ala and mute may become khafíf by suppression of their final Harakah and thus turn into Mufá’altun, by substitution Mafá’ílun (ii. 2. = U - - -), and Mutfá’ilun, by substitution Mustaf’ilun (ii 6.= - - U U as above). In other words the two feet correspond to the schemes U_U-U_ and U-U-U-, where a Spondee can take the place of the Anapaest after or before the Iambus respectively.
’Illah, the second way of modifying the primitive or normal feet, applies to both Sabab and Watad, but only in the ’Aruz and Zarb of a couplet, being at the same time constant and obligatory. Besides the changes already mentioned, it consists in adding one or two letters to a Sabab or Watad, or curtailing them more or less, even to cutting them off altogether. We cannot here exhaust this matter any more than those touched upon until now, but must be satisfied with an example or two, to show the proceeding in general and indicate its object.
We have seen that the metre Basít consists of the two lines:
Mustaf.’ilun Fá.’ilun Mustaf’ilun Fá’ilun
Mustaf’ilun Fá’ilun Mustaf’ilun Fá’ilun.
This complete form, however, is not in use amongst Arab poets. If by the Zuháf Khabn, here acting as ’Illah, the Alif in the final Fá’ilun is suppressed, changing it into Fa’ilun (U U -), it becomes the first ’Aruz, called makhbúnah, of the Basít, the first Zarb of which is obtained by submitting the final Fá’ilun of the second line to the same process. A second Zarb results, if in Fá’ilun the final n of the ’Watad ’ilun is cut off and the preceding l made quiescent by the ’Illah Kat’ thus giving Fá’il and by substitution Fa’lun (- -). Thus the formula becomes:—
Mustaf’ilun Fá’ilun Mustaf’ilun Fa’ilun
Mustaf’ilun Fá’ilun Mustaf’ilun{Fa’ilun
{Fa’lun
As in the Hashw, i.e. the first three feet of each line, the
Khabn can likewise be applied to the medial Fá’ilun, and for
Mustaf’ilun the poetical licences, explained above, may be
introduced, this first ’Arúz or Class of the Basít with its two
Zarb or subdivisions will be represented by the scheme
U U | U | U U | - - U - | - U - | - - U U | U U -
U U | U { U U - - - U - | - U - { - -
that is to say in the first subdivision of this form of the Basít both lines of each couplet end with an Anapaest and every second line of the other subdivision terminates in a Spondee.