The following are cements for machine belt joints. (1) Stir 1/2 pt. of good hot glue with a tablespoonful of glycerine and half a teaspoonful of turpentine. (2) Melt together in an old iron saucepan \ lb. of guttapercha, 1 oz. of pitch, 1 oz. of shellac, and 1 oz. of sweet oil. Use hot. (3) Dissolve gelatine in acetic acid. (4) Add as much tannin to glue as will make it ropy. (5) Melt together guttapercha, 20; pitch, 2; shellac,!: and linseed oil, 2 parts. (6) Digest guttapercha 3, and caoutchouc 1, in 4 of bisulphide of carbon. Belt joints should not depend entirely on the cement, but should be stitched as well.