Agni Purāṇa

328 - The rules of prosody

Agni said:

1-3. Ishall describe1 (the rules of) prosody in order as laid down by Pingala making use of the basic letters. There are eight ganas (classes), viz. magana, nagaña, bhagaņa, yagana, jagaña, ragana, sagaña and lagana made up of the letters ma, na, bha, ya, ja, ra, sa and ta. Each one of these gaņas is formed by three syllable instances. All the three syllables may be long orshort or the first or middle or final syllable may be long orshort. A syllable is long orshort according as the vowel at the end is long orshort. Ashort vowel becomes long when it is followed by a nasal sound or visarga (aspirated sound) or a conjunct consonant or a jihvāmüliya1 or a upadhmäniya2. Thus the gaņas are eight according to tradition. 

1.    The  Purāṇa summaries very briefly and does not give a clear definition. Hence the translation bas been rendered in such a way as to make it clear. 

1. A term applied to the visarga before k and kh and also to r, l and the gutturals, 

2. The visarga beforc the letters p and ph.