A cement for filling in joints and uniting iron surfaces is made as follows: Take 100 parts iron filings, no larger than rape seed and free from rust, 1/2 part of flowers of sulphur and 3/4 part of coarsely powdered sal-ammoniac. Wet the mixture with equal parts of vinegar and water and beat it, with a repetition of wetting until it becomes heated, brittle and dry. In this condition place it in the joints and pack in as tightly as you can with chisel and hammer, thus again making it moist and soft. Finally the joints are filled up evenly and permitted to become dry for 48 hours, after which time, if the work is well done, separate black drops will come out upon the hardened crust. For the preservation of this cement ram it into an iron pot and pour water over it. When you wish to employ it, pour off water and add to the mass taken out a large enough quantity of iron filings to give the requisite consistency and pour the water into the pot again.

(2) Another cement is composed of 1 part sal-ammoniac, 1 part sulphur, 30 parts iron fillings.

(3) Another cement is composed of pulverized cast-iron turnings, 50 parts; flowers of sulphur, 1 part; sal-ammoniac, 2 parts.

(4) Another cement is composed of pulverized iron filings 100 parts and pulverized sal-ammoniac 2 parts. Keep this compound in well-closed boxes in a dry place. For use, wet with equal parts of vinegar and water. Heat the cemented places only when they are wholly dry.