Called also lac sulphuris (milk of sulphur), though this name was originally given to an old preparation made with lime sulphate.

Preparation

From the sublimed sulphur, by first boiling it with slaked lime until the substances combine, and then adding hydrochloric acid, which unites with the lime while the sulphur is precipitated.

The reactions are somewhat complex, but may be thus represented: 3CaH1O2+6S2=2CaS5 + CaS2H1O4+2H1O and then, on adding the acid, 2CaS5+CaS2H1O4 + 6HC1=3CaCl2 + 4H1 O + 6S2.

The precipitated sulphur should be dried at a heat of 120° F.

Characters

A pure specimen is of pale dead-yellow color, without odor or taste, very smooth to the touch, not readily diffused in water. Under the microscope it presents opaque rounded granules, separate or in clusters.

[Sulphur Lotum, U. S. P. - Washed Sulphur. - Sublimed sulphur, thoroughly washed with water. It is wholly volatilized by heat, and, when moistened with water, does not change the color of litmus.]