1. – This preparation, destined for impregnating leather shoe soles, is produced as follows: Grind 50 parts of linseed oil with 1 part of litharge: next heat for 2 hours to the boiling point with ¾ part of zinc vitriol, which is previously calcined (dehydrated). The composition obtained in this manner, when perfectly cold is mixed with 8 parts of benzine and filled in bottles or other receptacles. To render this preservative effective, the soles must be coated with it until the leather absorbs it.