1. The art of Masonry includes the sawing and cutting of stones into the various shapes required in the multiplied purposes of building, and in placing them in a proper manner in the walls and other parts of edifices. It is divided into two branches, one of which consists in bringing the stones to the desired form and polish, and the other, in laying them in mortar or cement. 2. The rocks most used in building in the United States, are marble, granite, greenstone, scienite, soap-stone, limestone, gypsum, and slate. These are found in a great many localities, not only on this continent, but on the other side of the Atlantic. Of these stones, there are many varieties, which are frequently designated by their sensible qualities, or by the name of the place or country whence they are obtained; as _variegated_, _Italian_, _Egyptian_, or _Stockbridge marble_, and _Quincy stone_. 3. _The Stone-cutter._--Stone-cutters procure their materials from the _quarry-men_, whose business it is to _get out_ the stones from the quarries, in which they lie in beds, consisting either of strata piled upon each other, or of solid masses. Stones of any desirable dimensions are detached from the great mass of rock, by first drilling holes at suitable points, and then driving into them wedges with a sledge. These blocks are usually removed from the quarries, and placed on vehicles of transportation, by means of huge cranes, with which is connected suitable machinery. 4. The blocks of stone, received in their rough state by the stone-cutter, are divided, if required, into pieces of smaller size, by means of a toothless saw, aided by the attrition of sand and water. The other rough sides of the blocks are reduced to the proper form by means of steel _points_ and _chisels_ driven with a mallet. A kind of hammer with a point or chisel-like edge, is also used to effect the same object, especially in the softer kinds of stone. 5. For some purposes, the stones are required to be polished. This is especially the case with those employed in the ornamental parts of buildings. In the execution of this part of the work, the surface is rubbed successively with sand, freestone, pumice-stone, Scotch stone, crocus, and putty. When the face is a plane, the sand is applied by means of another stone, which is moved backwards and forwards upon it. In this way, two surfaces are affected at the same time. 6. In polishing irregular surfaces, the different kinds of stone are used in masses of convenient size; and the part applied to the surface to be polished is first brought to a form corresponding to it. The putty is an oxyde of tin, in form of powder. Crocus is the peroxyde of iron. The building-stone capable of receiving the highest polish is marble; and it is on this material that the stone-cutter, and the architectural carver or sculptor, exert their utmost skill; but some of the other stones which have been mentioned, possess the same quality to a considerable extent.