Anandakanda 1.5.20

1.5.20

tataḥ siddhaṃ vijānīyād dvaidhaṃ śulvasya dāpayet /
karmasaṃkhyāpramāṇena nāgo bhavati kāñcanam //

Then one should know it to be perfected, and give two shares of copper; / according to the measure of the procedures, lead turns into gold.