Kautilya's Arthashastra 14.3.64

14.3.64

trirātropoṣitaḥ puṣyeṇa śastrahatasya śūlaprotasya vā puṃsaḥ śiraḥkapāle mṛttikāyāṃ tuvarīrāvāsyodakena secayet //(?)

Having fasted for three nights, one should on the day of the star of Pushya fill with soil the skull of a man killed with weapons or put to the gallows, and, planting in it valli (vallari?) plants, should irrigate them with water. Having taken up the grown-up plants on the next day of the star of Pushya (i.e., after 27 days), one should manufacture a rope from them. When this rope is cut into two pieces before a drawn bow or any other shooting machine, the string of those machines will be suddenly cut into two pieces.