Pure balsam of copaiba, 9 oz.; lampblack, 3 oz.; indigo and Prussian blue, each 5 drachms; Indian red, ¾ oz.; yellow soap, 3 oz. Miz, and grind to the utmost smoothness.

Holes in Millstones are filled with melted alum, mixing burr sand with it. If the hole is large, put some pieces of burr-mill stones in it first, and pour in melted alum. These pieces of block should be cut exactly to fit. There should be small joints, and fastened with plaster of Paris. These holes should be cut at least 4 inches deep; there is then no danger of their getting loose.