DAGON. 734 DAHLBEKG. Menant, "Le niythe de Dagon," in the Revue de riiisloiic (Irs religions, vol. xi. (Paris, 18S6). DAG'ONET, Sir. King Artliur's fool, in the '■Round Table" legends. The Elizabethan drama- tists frequently allude to him as a type of the court jester. DAGUERKE, da'gar', Louis Jacques :^IA^-- DE (ITSyiSol). A French painter and physi- cist, born at Cormeilles, Seine-et-Oise. He first became a scene painter under Degoti, and was so .successful in this art that he began to paint extensive panoramas, and finally evolved the diorama, which attracted much attention. About 1829 he began to interest himself in the discov- eries which Ijecame famous under his name. He entered into a correspondence with Nicephore Ni&pce, who had been studying in the same di- rection since 1814. Together they invented the art of photography on metal, the well-known daguerreotype process, the improvement of which was to result in modern photography. Before the completion of their experiments Nifepce died. In 1830 the discovery was made known, and im- mediately its value was appreciated. Daguerre was given a pension of 6000 francs and made a member of the Legion of Honor. While he was still laboring to bring his work nearer perfec- tion he died suddenly at Petit-Brie-sur-ilarne, near Paris. He wrote the following volumes de- scriptive of his inventions: Historique et de- scription rles proccdcs du daguerreotype et dio- rama (1880) and oureau moyen de preparer la couclie sensible des plaques destinees a recevoir les images photographiques (1844). Consult Ernouf, Les inventeurs du gaz et de la photo- graphie (Paris. 188.5). See Daguebbeottpe Process; PiioxotiRAPuY. DAGUERREOTYPE ( da-gei-'6-tip ) PRO- CESS (Fr. daguerreotype, from Daguerre -{- Gk. Tiiros, typos, impression). The original photo- grapbic process, as introduced by its inventor, Daguerre, in 1830. The pictures are positive or direct, though they appear as negative when viewed at certain angles, and are the result of the successive action of the vapors of iodine, bro- mine, and mercury upon a highly polished sur- face of chemically pure silver. The r.anipula- tions involved in conducting the process are: (1) Cleaning and polishing the plate; (2) ren- dering the plate sensitive; (3) exposing it in the camera: (4) developing the latent image; ( 5 ) fixing the picture. A copper plate of moderate thickness is first coated with silver by electro-plating and polished as highly as possible; it is then exposed first to the vapor of iodine, and then to the vapor of bromine for a length of time, ascertained in practice by watching the succession of prismatic colors which begin to appear with the first con- tact of the vapor. The plate is then exposed in a camera, and the development of the latent im- age, which is the next operation, is effected by subjecting the plate to the action of the vapor of mercury, which attaches itself to the various parts of the picture in proportion as it has been acted on by the light. Those portions of iodide and bromide of silver nnaftected by light are next removed by immersing the plate in a solu- tion of hyposulphite of soda ; and the picture is subsequently fixed and intensified by pouring over its surface a solution of hyposulphite of soda and chloride of gold, and applying heat; by which means it is coated with a thin film of metallic gold, and thereby rendered so perma- nent that it requires a chemical solvent for its removal. It may be mentioned in conclusion that though Daguerre published in 1839 the first practicable process for taking pictures by the agency of light, his experiments would seem to have been suggested by the researches of Nifepce, who, about 1820, obtained impressions on silver ]jlates rendered sensitive by being coat- ed with asphaltum saturated with oil of laven- der. See Photoukaphy. D'AGtTESSEATJ, da'ge'su'. See Aguesseau. DAGUPAN, da'goo-piin'. A town of Luzon, Philippines, in the Province of Pangasinan, sit- uated eight miles from Lingayen, near the Gulf of Lingayen (Map: Luzon, C 2). It is the ter- minal of the Manila-Dagupan Railway. The surrounding region, generallv level, is veiy fer- tile. Population, in 1898, 10,000. DAHABEAH, dli'ha-be'a ( Ar. dhahabiya, from dhahaba, to go). The name given to barges on the river Xile, much used by tourists, to whom they are hired by the week. They resem- ble in their conveniences and comforts the house- boats so jjopular on English rivers. DAHL, dtil, .JoiiAxx Kristex Clwses ( 1788- 18.57). A Xorwegian landscape painter, born at Bergen, February 24, 1788. His parents wished him to enter the Church, but he w-as determined to study art, and in 1811 entered the Academy at Copenliagen. In 1S18 he entered the Acad- emy at Dresden, and in 1821, after his return from Italy, he was made professor there. He was a pioneer in Norwegian landscape. Though very rugged in style, he painted with a hard and dry effect. In spite of this, he stood in the front rank of his contemporaries, especially between the years 1820 and 1830. He died at Dresden, October 14. 18.57. Among his most prominent works are: "Danish Coast by Moonlight" ( 1828) ; '•Storm at Sea" (1823): Great Norwegian Landscape" (1850): and "Winter Landscape." Consult Aubert, Maleren Professor Dahl 1~8S- JS.yy (Kristiania, 1892-04), DAHX, Vladimir Ivaxovitch (1801-72). A Russian author, born in Lugansk (Government of Ekaterinoslav ) . He was educated at Dorpat, and in 1828-31 accompanied the Russian army in a medical capacity in the Turkish and Polish campaigns. Subsequently he was a Government official at Orenburg. His studies in Russian eth- nography and philology are valuable, in particu- lar his Dictionary of Existina Russian Dialects (4 vols., 1861-68; 2d ed. 1882). His works in belles-lettres were collected at Saint Petersburg in 1860-61 (8 vols.). DAHLAK, da-liik', or DAHALAK, da'ha- lak'. An archipelago (a dependency of Italy) just off Massawa. Abyssinia, consisting of a num- ber of islands of coral, rock, and sand (Map: Africa, H 3). Three only have a permanent pop- ulation. The entire area is about 420 square miles, the larger portion of which is taken up by the main island, Dahlak-el-Kebir. 32 miles long and 18 wide. The chief occupation is fish- ing for pearls and sponges. Domestic animals are raised to some extent. The permanent pop- ulation is about 1.500. mostly Abyssinians. DAHLBERG, diil'berg. Erik, Count (1625- 1703). A Swedish military engineer, born in
