Arthashastra
दश पणिको योजने दूतो मध्यमः, दश उत्तरे द्वि गुण वेतन आ योजन शताद् इति ॥
A messenger of middle quality shall receive 10 panas for each yojana he travels; and twice as much when he travels from 10 to 100 yojanas.
english translation
daza paNiko yojane dUto madhyamaH, daza uttare dvi guNa vetana A yojana zatAd iti ॥
hk transliteration by Sanscript