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LEFT BUILDING STONE 228 BUILDING STONE crued profits, bring the value of the share to par. The number of shares each menAer may hold varies in different as- sociations, the general rule being not less than two nor more than 25, the latter limitation being intended to prevent speculation. Building and loan associa- tions are formed on two plans, called ter- minal and serial. The terminal associa- tions compel all members to begin pay- ments on the same day. A new member joining after the beginning of the as- sociation is thus forced to pay arrear- ages. This is avoided in serial associa- tions by allowing new members to join at stated intervals, usually six months or a year, without the payment of arrear- ages. The advantages of building and loan associations are: That each share, whether borrowed upon or not, has cred- ited to it a pro rata amount of all profits declared. Loans are generally advanced to within 80 per cent, of the appraised value of the property. No large salaries are paid. All officers, appraisers, au- ditors, etc., are elected in open meeting. Members may withdraw at any time after the first year, obtaining a fair share of the profits. Loans are invari- ably secured by first mortgage. Only members may obtain loans. Mortgages may be paid off at any time. There are no speculative features, the association buys nothing, the borrowing member making all contracts. In 1918 there were 7,484 building and loan associations in the United States, reporting 4,011,401 shareholders. These associations had as- sets aggregating $1,898,344,346. The total receipts and disbursements balanced at $1,325,313,352. BUILDING STONE, any stone used in the construction of buildings. The stones mostly employed are granite, sandstone, limestone, marble, serpentine, and trap. In order that a stone may be used to advantage for building purposes, it must possess certain physical and chemical properties ; these are durability, permanency of color, crushing strength, elasticity, and cheapness. Stones vary greatly in their durability, depending upon their chemical composition, and the purposes for which they are used. As soon as a stone is quarried, it becomes exposed to changes in temperature, caus- ing expansion and contraction of its par- ticles and ending ultimately in its disin- tegration; to the chemical action of rain and atmosphere; and to frost and vari- ous mechanical forces, all tending to weaken it. Granite. — The best building stones are those which have a compact formation, are not susceptible of chemical changes, and are easily worked. Granite comes nearest to perfection in this line. It is the strongest stone in use, and, having been employed for ages, is found to with- stand severer tests than any other stone. It is a very hard silicious rock, having a massive and granular crystalline struc- ture, containing the minerals quartz, feldspar, mica, horneblende, and, occa- sionally, a little iron. The general color is gray, due to the presence of black mica or horneblende in the white quartz and feldspar. The red and pink varieties are caused by the presence of a red feldspar. The greatest granite beds in the United States are found in Maine and Massa- chusetts. These granites are chiefly gray. A large amount of red gi'anite is quarried in Nova Scotia, Scotland, and Sweden. Limestone. — Next to granite, the most durable building stones are the lime- stones. These vary greatly in both struc- ture and color. One of the best varieties of this stone is the Indiana limestone. It has a white, or cream color, is of fine granular structure, and is readily worked. Many of the largest buildings in New York and Chicago are built of this stone. One of the best English building stones is the dolomite, or mag- nesian limestone of the Permian forma- tion, which ranges from Nottingham to Tynemouth. It is a double carbonate of lime and magnesia, containing a varying proportion of silica. The Houses of Par- liament are built of this dolomite, which unfortunately decays rapidly under the influence of the London atmosphere. Marble. — Marble is a purer grade of limestone, of a finely crystallized struc- ture. It is composed almost entirely of calcium carbonate. Its color varies from a pure white to a black, and it often oc- curs with a red, yellow, or brown color. These colors are due to the presence of carbonaceous matter and iron oxides. Marbles occur in the United States in the beds of the Silurian limestone, which border the Appalachian Mountains, and also in the Rocky Mountains. The best grades are quarried in Vermont, and a very good marble for building use is found in western Massachusetts and in Connecticut. In Europe, the principal sources of marble are northern Italy, France, Spain, and Portugal. The Nu- midian marble from Algeria has a great international reputation. Sandstone. — Sandstones are composed of consolidated sand, and vary in color, structure, and composition. They are, as a rule, composed principally of quartz. The other substances they contain are chiefly carbonate of lime, alumina, and oxide of iron. In color, they vary from a gray, through buff and red, to brown;