Anandakanda 1.9.10

1.9.10

śuddho bhaveccaturyāmātpāradaḥ syādrasāyane /
<rasabhasmakramaḥ; prathamaḥ prakāraḥ>
ūrdhvādhastātkhajīrṇasya sūtasya samagandhakam //

after four watches, the mercury becomes pure and fit for rejuvenation therapy.
<Method of calcining mercury; the first method>
With sulphur equal [in weight] to the quicksilver that has digested mica from above and below,