laghuni vai samamnata
dasa pañca ca nadika
te dve muhurtah praharah
sad yamah sapta va nrnam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Fifteen laghus make one nadika, which is also called a danda. Two dandas make one muhurta, and six or seven dandas make one fourth of a day or night, according to human calculation.