Anandakanda 1.4.151

1.4.151

mardayecchigrutoyena gandhakaṃ tena bhāvayet /
saptāhaṃ marditaṃ gandhaṃ cārayetpāradasya ca //

one should grind with the water of śigru, and macerate the sulfur with that. / Sulfur ground for seven days should be fed to mercury;