Page:The New International Encyclopædia 1st ed. v. 14.djvu/41

MORSHANSK. 29 MOBTARA. extensive trade in agricultural products and live stock. Population, in 18'J7, 27,756. MORTALITY, Statistics of. See Vital Statistics. MORTAL SIN. In Roman Catholic theology, the name given to the graver class of sins, in distinction from venial sins (q.v.). For a sin to be mortal, it must be a conscious violation of a known divine law, decided upon deliberately by a free will, and it nmst be in a matter of im- I)ortance; thus, for example, the theft of a few |icniiies, without aggravating circumstances, would not be a mortal sin. Mortal sin, as its name implies, is believed to destroy absolutely the divine life of grace in the soul and render it deserving of eternal punishment, unless remitted by perfect contrition, or b}' attrition in conjunc- tion with the sacrament of penance (q.v.). MORTAR (OF., Fr. morticr, from Lat. »ior- tariiim, mortar; connected with tnarcus, hammer, Skt. mar, to crush). A mixture or paste of cement or lime and sand. Mortars may be clas- sified according to the nature of the cementing substance used, into: Common lime mortar, hydraulic lime mortar, and cement mortar. Common Lime Mortab. Jlortar made of com- mon lime is extensively used beeau.se of its in- trinsic cheapness and the ease with which it can lie prepared. It sets or becomes hard only in air, however, and should consequently not be used under water or in wet places. Its small strength compared with cement mortar, however, limits its use to strictures in which great strength is not required. In making lime mortar the proportions of the mixture are usually about one volume of lime to from two and one-half to three volumes of sand. The lime is placed in a layer in a shallow bo.x or in a depression scooped out of the sand and then sprinkled with a quan- tity of water from two and one-half to three times I lie volume of the lime. This being done, the lime sliould be left to 'slack' undisturbed. It is gen- erally held by engineers that the lime should be slacked at least twenty-four hours before it is mixed with the sand. Tliis is frequently not dime, through haste or carelessness, in common building operations. It is also important that all the water required for slacking should be added to the lime at one time, since the addition of water after slacking has begun retards that ]irocess and results in the production of a lumpy mortar. After the lime has been slacked the sand is spread in a layer over its top and the two materials are mixed and remixed by means of a hoe or shovel until a uniform jiaste is secured. The mortar is then ready for use. IIydraclic Lime Mortar. In hydraulic lime mortars the proportions of the ingredients and the manner of mixing them are substantially the same as for common lime mortar. The only cliange practically is the use of hydraulic lime instead of common lime. See Cement. Cement Mortar. The most valuable of all mortars are those made with hydraulic cements (see Cement) as a binding material. The pro- portions of the ingredients that are most com- monly use are one part cement and two or three parti^sand. To make the mixture about half the sand is spread in a layer over the bottom nf the mixing box: the cement is then spread in a layer over this sand bed. and is in turn covered . with the remainder of the sand. The mass of cement and sand is then turned and re-turned with a shovel until the two ingredients are thoroughlj' intermingled. Water is then added to the mixture, which is again turned by the -shovel until it is uniformly wet. Grout. A thin or liquid mixture of lime or cement is called grout. It is used to fill up small interstices by pouring it upon the masonry, into the voids of which it is expected to find its way because of its liquid nature. For a comprehensive discussion of mortars, see Baker, A Treatise on Masonry Construction (New York, 1902). See Building. MORTAR. A type or form of ordnance used for high-angle tire. In design it is short in length in proportion to its calibre or size of bore. In the United States and England mortars are almost entirely used for coast defense purposes. In the former countiy mortar batteries consist of either eight or sixteen mortars each, four mortars to a pit. The pits arc fortified with parapets constructed of sand reenforced on the interior by a concrete wall. They are separated by sub- stantial traverses which contain the necessary magazines, bomb-proofs, etc. ( See illustration under Fortification.) The batteries are con- trolled by an oflicer (the predicting officer), who observes the plotting board, the target, and the effect or destination of the projectile, in order to give the projjer direction and elevation to the men working the pieces in the pit. France has taken the lead in the manufacture of these types of ordnance, the Creusot works of Messrs. Schneider & Co. being perhaps the best known in the world. The use of field mortars has not been as yet put to the test of modern battle conditions, so that their employment is largely a matter of conjecture. In 1903 Russia led the world with a regularly organized and equipped division of 24 batteries, C mortars to a battery. Austria and Germany come next, the latter country dif- fering from Russia in details of organization. Although the advantages of field mortars are conceded to be greater than their disadvantages, the latter are still sufficiently important to delay their general immediate employment. The most important disadvantage is the difficulty of getting men so thoroughly trained that they are equally expert with the ordinary flat projectory field gun and the high-angle mortars. Another defect in field mortars is their utter inability of de- fending themselves at close range. For illus- tration of the 12-inch breech-loading mortar used in the United States service, see Coast Artillery, and for an illustration of the 10-inch cast-iron muzzle-loading mortar, see Artillery. See also Coa.st Defense; Howitzer; Ordnance. Under the latter head the construction of a mod- ern mortar is described. MORTARA, mor-til'ra. A town in the Prov- ince of Pavia. Italy, situated on the Arhogna, and at the junction of several railroads. 25 miles southwest of .Milan (Map: Italy. C 2). There are a Gothic church (San Lorenzo), with paint- ings, a theatre, and a high school. Manufactures of machines and hats are carried on. At the battle of Mortara. March 21. 1849. the Austrians defeated the Sardinians. Population (commune), in ISSl. snsS: in 1901, 80.31. MOBTARA, En(,AR. A .fewish boy whose al- leged abduction excited nuich interest in Europe in 1858 and following years. He was the son of