New version available here: vedabase.io

SB 3.11.9

dvādaśārdha-palonmānaṁ
 caturbhiś catur-aṅgulaiḥ
svarṇa-māṣaiḥ kṛta-cchidraṁ
 yāvat prastha-jala-plutam
Synonyms: 
dvādaśa-ardha — six; pala — of the scale of weight; unmānam — measuring pot; caturbhiḥ — by weight of four; catuḥ-aṅgulaiḥ — four fingers by measure; svarṇa — of gold; māṣaiḥ — of the weight; kṛta-chidram — making a hole; yāvat — as long as; prastha — measuring one prastha; jala-plutam — filled by water.
Translation: 
The measuring pot for one nāḍikā, or daṇḍa, can be prepared with a six-pala-weight [fourteen ounce] pot of copper, in which a hole is bored with a gold probe weighing four māṣa and measuring four fingers long. When the pot is placed on water, the time before the water overflows in the pot is called one daṇḍa.
Purport: 

It is advised herein that the bore in the copper measuring pot must be made with a probe weighing not more than four māṣa and measuring not longer than four fingers. This regulates the diameter of the hole. The pot is submerged in water, and the overflooding time is called a daṇḍa. This is another way of measuring the duration of a daṇḍa, just as time is measured by sand in a glass. It appears that in the days of Vedic civilization there was no dearth of knowledge in physics, chemistry or higher mathematics. Measurements were calculated in different ways, as simply as could be done.