LAPIDARY WORK. 771 LAPLACE. cutting, grinding, and polishing precious stones. Tliis industry has been practiced, in a crude way, from very ancient times. At first only the natural faces, caused by the crystallographic structure of the gem, were polished, but soon the art of enhancing the beauty of the gem by cut- ting additional faces, or facets, was learned, al- though no attempt was made by the earliest lapidaries to give the gem a symmetrical form. Often the facets were elaborately carved and a hole drilled through the centre, so that the stones might be strung like beads or sewn upon gar- ments. About 12So a guild of gem-cutters was established in Paris, and from that time the art of the lapidary has steadily advanced. Xo modern art dejiends more upon the skill of the workman. Although power has been ap- plied to some of the machinery employed, yet the tools used are of the simplest nature. But the greatest knowledge and dexterity are re- quired to manipulate these instruments, as a stone might be ruined by one careless stroke. Xot only e.xperience and skill, but a knowledge of optics, physics, mineralogy, and ciystallog- raphy, is necessary for the execution of high- grade work. In earlier times the greatest pos- sible size of the gem was the principal end sought by the lapidai-y, but now such considerations as flawless structure, symmetrical form, and perfect coloring are of equal importance, and to secure these the size of the gem is often sacrificed. The first step in lapidary work is to cement the gem upon an ebony or ivory holder about the length and half the diameter of an ordinary lead pencil. The facets are then cut upon a copper disk, surfaced with diamond-powder, and rotated by a hand-turned crank. Close to the wheel there is a cutting-rest in the form of an inverted cone, having little notches in it from top to bottom, in which the end of the gem-holder can be securely placed, thus insuring a perfectly flat cut at any desired angle. After being cut, each facet is polished by means of a revolving wheel upon which some polishing material, as emery or rotten-stone, is spread. This wheel is usually run by an electric motor, and made of llie material best suited to the quality of the stone to be polished. For a very soft stone, like the opal or turquoise, a flannel-covered wooden wheel niiglit be used. Gems are carved by means of a lathe, with tiny wheels or disks, whose edges are primed with diamond-dust. When a stone is to be di- vided, a small, thin disk of tin is used for cut- ting, operated on the principle of a circular saw. For diamonds a different method of cutting and polishing is employed. See Di.^Moxn. LA PIEDAD, la pyA-nan'. A town of the State of Michoacan. ifexico. sitiiated at the northern bovindary of the State. (Vl miles south- west of fJuanajuato. and on the left bank of the River I.erma. which is here crossed by a fine bridge (^lap: !Mexicn. IT 7). .Vdjacent to it is an important agricultural district. Population, lf(,nnn. Tn ISTl it received the title of city. LA PIJARDIERE, 14 p.'-'zhar'dynr'. Lons PE L. CoiR DE (lS32-ni). A French author and antiquary, born at Xantes. and educated at the Ecole des Phartes. He became keeper of the archives of the Sninte-Oenevieve Library in ISfiO. and of that of Hi'rault in 1872. He committed suicide at 'Nfontpellier in 1801. He was a special student of MoliSre. Among his works (some under the name Louis La Cour) are: Lcs garfons da cafe dc I'aiis, par (Jaston Vorlac (1850) ; Le pure uiix ccrfs (185!)) ; Kapport sur la dixouverte d'liii autoyraphe de Molicre (1873); Molii-re (i fvzinas vn IdoO-ol (1885) ; and Molicre, son si- jour a Muntpellier en Kio.'i-oo (1887); besides editions of BrantOme, of Bonaventure, Desperiers, of Rabelais, and of a facsimile of the earliest edi- tions of iloliere for the Academie des Biblio- philes. He founded the historical review Chfo- niques du Laiiguedoc. LA'PIS LAZ'TJLI, or L.zrBlTE (Xeo-Lat., stone of azure, from Lat. lapis, stone, and ML. laztilus, lazuritts, laztir, ilGk. Xafoi/pioK, la:ou- rion, from Ar. liizward, from Pers. luzhicard, named from Lajicard in Persia, where the min- eral abounds). A mineral substance containing sodium, aluminum, silicic acid, and sulphur. It crystallizes in the isometric sj-stem. but is usually found massive, having a beautiful ultra- marine or azure-blue color. The mineral was highly esteemed for its medicinal qualities by the ancients, who pulverized it and mixed it with milk, using it as a dressing for boils and ulcera- tions. Pliny and other Roman writers called it sapphire. It was used among the Egj-ptians in their jewelry, and among the modern nations it has been employed for engraving, for vases, in ornamental and mosaic work, and for altars and shrines. Lapis lazuli occurs in granite, and iir crystalline limestone, the finest specimens coming from China. Siberia, Persia, and Chile. When i)Owdercd it forms the pi<;incnt called ultramarine, which, however, has been replaced by an artificial product. See rLTR.>l.RlN"E. LAP'ITH33 ( Lat., from Gk. AairiOai. Lapi- thai). In Greek legends, a people who inhabited the mountains of Tbessaly. They derived their name from a mythical ancestor. La pit lies, a son of Apollo, and the brother of Centaurus, the equally mythical ancestor of the centaurs (q.v. ). In legenil the l.apithie appear especially in their conflict with the centaurs. At the mar- riage of King Pirithous to Hippodamia, the centaurs flushed with wine offered violence to the women, and in the war that followed the centaurs were neaily destroyed. Theseus was said to have heljiod Pirithous in this struggle, and it consequently assumed a prominent place in Athenian literature and art. It is represented on the friezes of the "Theseum" at Athens, and the Temple of Apollo at Phigaleia. and on the metopes of the Parthenon, as well as on va.ses. They were said to have been crushed by Agimius and the Dorians, assisted by Hercules. There seems reason to believe that amid all these legends the Lapitha? were a folk of some dejrree of civilization, dwelling in early times in Thes- saly. LAPLACE, la'ph^s'. .Josrfc DE (1000-55). bet- ter known as Placeus, a French Reformed clergy- nuin. He was a preacher at Xantes, and in' l<i32 was appointed i)rofessor of theology at Saumur. His great work is De Utatu Uominis Lapsi (1040). in which, like Amyraut (q.v.), he sought to modify the strict Calvinism of his Church, but unsuccessfully. His complete works were pub- lished at Franeker in 10i)'.l in two volumes. LAPLACE, Pierre Simon, Marquis de ( 1749- 1827). The greatest of the French astrono- mers. He was born at Beaumonten-.^uge (CalvadosK His father, a poor farmer, was
