This differs from the preceding simply in the circumstance, that alcohol is used as the menstruum instead of water. it is prepared in the same manner, and is intended to be of the same ammoniacal strength. its only advantage is, that, in consequence of its alcoholic menstruum, it sometimes admits of admixture with substances for external use, with which water might be chemically incompatible, as with the resinous and gum-resinous tinctures, and alcoholic solutions of camphor, and the volatile oils. With these it is occasionally associated in the preparation of rubefacient liniments, or of mixtures for internal use; which, however, always require to be diluted freely with water at the time of exhibition. The spirit of ammonia may be used internally for the same purposes as the watery solution, the carbonate, or the aromatic spirit. The dose of the U. S. spirit, which has the sp. gr. 0.831, is from ten to thirty minims.