BTJILDING-STONE. 651 BUISSON. to become permanent. In Europe the Welsh of crystallization. In sedimentary rocks the slate-quarries and those of Ardennes, France, individual grains are bound together by cement- an> the greatest producers. ing material, such as silica, iron oxide, or lime QlARRYiXG .XD Drkssin'G. The methods of carbonate, which has been deposited between quarrying building-stone vary according to the them as described ;il)ove. In trying climates a nature of the stone. In all methods the object stone nuist be bard and dense to insure dura- aimed at is to obtain large and well-shaped bility, but in mild climates very soft, porous blocks free from incipient fractures. For this atones can often be emi)b)yed. The resistance reason the use of explosives is resorted to as lit- which a stone offers to frost action is often tested tie as possible. (See Qiaruy, Quarrying.) by soaking it in water, and then freezing it, the Dressing stone is very largely hand work, al- iJrocess being repeated a number of times, and though many kinds of machinery are also em- note taken of any disintegration that occurs, ployed f<n- polishing, planing, aiid sawing soft A second but inaccurate method consists in boil- stones, and for splitting slate. See Stone-Cut- ing the stone in a sulphate of soda solution and TING ..Ni) Dressing. then allowing it to dry; the swelling of the rni?ABii.iTY. The ability of a stone to resist soda-crystals in forming as the water evaporates deterioration by changes in weather and tern- exerts a far greater pressire than frost action, perature. by chemical agencies in the atmos- The liability of building-stone to decay is some- phere and rain, by growing organisms, and by times increased by the presence of injurious min- ordinary wear and tear — or^ in other words, the erals. Pyrite grains decompose, yielding rust- durability of a building-stone — is obviously an stains, and mica at times behaves in a similar important factor in its value for construction manner. Marbles may contain both pyrite and purposes. Granites are liable to disintegration actinolite, the decomposition of the latter yield- ■chielly from the constant contraction and expan- '"S I'^tle bits of greenish clay that absorb mois- sion caused bv natural temperature chanses. ture. They absorb verv little water, and thus suffer The crushing strength of a stone is often very verv little from 'the expansion of the contained fireat, indeed far greater than is really necessary, water when frozen, and they are not nnioh affect- 'Granite and syenites are among the strongest, ed bv anv of the chemicals' ordinarilv carried in having a crushing strength of 25.000 to .30,000 the "air and rain. Limestones suffer less than l"™"'ls per square inch; sandstones range from granite bv mere expansion and contraction, but 10>t)00 to 1,5,000 pounds; and limestones and make up for this bv greater susceptibilitv to the "larbles 8000 to 12,000 pounds per sqxiare inch, chemicals in the air and rain. They "do not The lower limit even is probably sufficient in absorb much water, and are therefore but little "lost cases. disturbed bv its freezing. Sandstones, being "^ anous kinds of solutions have been tried for porous, absorb more water than limestone or pieserving the life of stone, but none of them have granite, and are particularlv subject to dis- ^"^^ f""'^ *« " perfectly satisfactory. For the integration bv freezing. The" following figures strength of various kmds of building stones, see from the United States census of 1890 show the ^teengtii of Materials. See also B.vthstone; life of various kinds of building-stone in Xew Browxstone; Caen Stone: Freestone; Gban- York Citv: ^^' Limestone; Marble; Sandstone; Slate; ■ ' Stone, Aktificiai. ; Building ; and Masonry. For Ki.ND OF STONE LiFE IN Yeabs comprehensive popular treatises on building Coarse brownstoue ,. 5to 10 stones consult- Hall Trenthtp mi the lii/ililiiin Fiue laminatedbrownstone 20to 50 sioiies, toubuii . nan, irear^e onine liuiMmg Coniiiaetbrnwnstone 100 to 200 "«» Ornamental l>tone.<i of Great Britain (Lon- Uoaise fossiliterous limestone 20 to 40 don, 1872); Merrill. Stones for Building and M^:s:'^ardX^itie:;::::::::::::::::::::::: """ t Decoration (New York, isod; joimsm^ r^e .Marble, flni-doloioitic 60to 80 Malrriah of Constrnclion (New ork, 1899). GraulU^"" ??to2M BUISSON, bwe'.SON', FERDINAND EdOUARD Nova Sc'otia Wiidstone.'."!!;!!!!".".'.'!!.'.".'!.'.'.'.';.'! 60 to 200 (1841 — ). A French adininistralur, publicist, and pedagogue. He was born in Paris. In 1871 be Speaking generally, the durability of any stone was appointed inspector of elementary schools by depends on its relation toward atmospheric -Tules Simon, then Minister of Public Instruction, agencies. If a stone is dense, there is little pore- His nomination was bitterly attacked, more par- space for moisture to soak in and exert a pi"ying ticularly by Dupanloup. Bisliop of Orleans, who action when it expands in freezing. Many stones denounced in the National Assembly several contain small quantities of moisture naturally, pamphlets publislied by P.uisson in which lie rec- Tvhich is known as quarry-water, and the freez- ommended the exclusion from the schools of all ing of such water, if the stone is quarried in cold moral instruction not purely secular, and the weather, may aid in the disintegration of the omission of sacred history from the curriculum rock. If the rock is quarried in warm weather, of the younger pupils. Compelled to resign, the quarry-water is evaporated, and any mineral Buisson was afterward.s appointed commissioner matter which it holds in .solution is de|iosited to the expositions held in Vienna (1873) and around the gi-ains of the .stone, cementing them Philadel])hia (187(i). In IS7S he became chief together, and this is why some stones harden inspector of elementary education, and in the fol- after quarrying. The porosity of building-stone, lowing year ,Iules Ferry appointed him director or its absorption, is variable, being from ^.^ to 2 of that department. The introduction of the per cent, in granites. 2 to 4 per cent, in lime- new education in the elementary schools uniler stones, and 2 to 8 per cent, in sandstones. The his jurisdiction has been remarkably rapid. In hardness and crushing strength of a stonedepends 1896 he resigiied and was appointed to the chair, on the firmness with which the particles are of pedagogy in the Facultf' (les Lettres at Paris, bound together. In igneous and metamorphie He is the author of a Dietiuiinairv dc pedagogic Tocks the particles are interlocked as the result (1882-84). Vol.. III.— »2.
