The first member of a tat-puruṣa samāsa preserves its original accent when the second term is gādha or lavaṇa and the compound expresses 'a measure or mass'.,
Thus श꣡म्बगाधमुदकम्, अरित्र꣡गाधमुदकम् 'water as low or fordable as a Samba or an Aritra i. e. of the depth of an oar or a pestle'. गो꣡लवणम्, अ꣡श्वलवणम् 'so much salt as may be given to a cow or a horse'. These are Genitive Tatpurusha compounds. शम्ब is formed by adding वन् to शम् (Unadi. IV. 94), and has acute on the first 6.1.197. अरित्र is formed by the affix इत्र added to ऋ 3.2.184, and has acute on the middle 3.1.3: गो is formed by डो (Unadi II. 68) and has acute on the final ओ; अश्व is formed by क्वन् affix added to अश् (Unadi. I. 151), and has acute on the first 6.1.197. The word प्रमाण here denotes 'quantity', 'measure', 'mass', 'limit', and not merely the length. The power of denoting measure by these words is here indicated by and is dependent upon accent.
When not denoting प्रमाण we have परमगाध꣡म् and परमलवण꣡म् ॥,