Rasaprakashasudhakara 10.21

10.21

vṛntākākāramūṣāyāṃ nālaṃ kṛtvā daśāṃgulam
dhattūrapuṣpavaddīrghaṃ sudṛḍhaṃ caiva kārayet //

In a crucible shaped like an eggplant, one should attach a pipe ten finger-breadths long, / long like a dhattūra flower, and very sturdy;