Granite is polished in many different ways, the method employed depending upon the nature and quality of the granite, the varieties of which are very numerous. The following method is the one generally adopted. The surface left by the axe presents a succession of ridges and furrows •, these ridges must be rubbed down with iron rubbers and sharp coarse sand and water. When all the tool marks are removed, and an even face has been produced, the rubbing is con tinued with emery powder of varying degrees of fineness, the same iron rubbers being used. Lastly, the stone is rubbed with a woollen or linen boss on which fine flour emery is sprinkled and moistened with water, the final polish being given with putty powder (oxide of tin) and a felt block. A good polish, which can be obtained only by persistent rubbing, will keep its lustre undimmed for half a century at least. For the sake of speed and cheapness, hydrochloric acid (spirits of salts), oxalic acid, and similar acids are sometimes used for polishing; but the polish soon disappears, and the face of the granite is to some extent destroyed.