DAMPERS DANAE. 



589 



'DAMPERS ; certain movable parts iu the inter- 

 nal frame of a piano-forte, which are covered with 

 cloth, and, by means of a pedal, are brought into 

 contact with the wires, in order to deaden the vibra- 

 tion. 



DAMPIER, WILLIAM, a celebrated English navi- 

 gator, was born in 1652. He was descended from 

 a good family in Somersetshire ; but, losing his father 

 when young, he was sent to sea, and soon distin- 

 guished himself as an able mariner. In 1673, he 

 served in the Dutch war, and was subsequently an 

 overseer to a plantation in Jamaica. He next visited 

 the bay of Campeachy as a logwood-cutter, and, 

 after once more visiting England, engaged in a band 

 of privateers, as they called themselves, although in 

 reality pirates, with whom he roved on the Peruvian 

 coasts. He next engaged, in Virginia, in an expedi- 

 tion against the Spanish settlements in the South 

 seas. They accordingly sailed in August, 1683, and, 

 after taking several prizes on the coasts of Peru and 

 Chili, the party experienced various fortune, but no 

 very signal success. Dampier wishing to obtain 

 some knowledge of the northern coast of Mexico, 

 joined the crew of a captain Swan, who cruised hi 

 the hopes of meeting the annual royal Manilla ship, 

 which, however, escaped them. Swan and Dampier 

 were resolved to steer for the East Indies, and they 

 accordingly sailed to the Piscadores, to Bouton island, 

 to New Holland and to Nicobar, where Dampier and 

 others were left ashore to recover their health. Their 

 numbers gave them hopes of being able to navigate 

 a canoe to Achin, in which they succeeded, after en- 

 countering a storm, which Dampier -has described 

 with great force and nature. After making several 

 trading voyages with a captain Weldon, he entered, 

 as a gunner, the English factory at Bencoolen. 

 Upon this coast he remained until 1691, when he 

 found means to return home, and, being in want of 

 money, sold his property in a curiously painted or 

 tattooed Indian prince, who was shown as a curiosity, 

 and who ultimately died of the small-pox at Oxford. 

 He is next heard of as a commander, in the king's 

 service, of a sloop of war of twelve guns and fifty 

 men, probably fitted out for a voyage of discovery. 

 After experiencing a variety of adventures with a 

 discontented crew, this vessel foundered off the Isle 

 of Ascension, his men with difficulty reaching land. 

 They were released from this island by an East India 

 ship, in which Dampier came to England. Here 

 ends his own account of his extraordinary adventures ; 

 but it seems that he afterwards commanded a ship 

 in the South seas, as also that he accompanied the 

 well known expedition of captain Woodes Rogers as 

 pilot. Dampier's Voyages, in three volumes, have 

 been many times reprinted. They are written by 

 himself in a strongly descriptive style, bearing all 

 the marks of fidelity ; and the nautical remarks display 

 much professional and even philosophical knowledge. 

 His observations on natural objects are also extremely 

 clear and particular; and he writes like a man of 

 good principles, although he kept so much indifferent 

 company. 



DAMPS are certain deleterious gases which are 

 extricated in mines. They are distinguished by 

 miners under the names of choke-damp ana fire-damp. 

 The former is found in the deepest parts of mines. 

 It extinguishes candles, and often proves fatal when 

 it lias been suffered to accumulate in large quantities. 

 It consists for the most part of carbonic acid gas. 

 The fire-damp, which prevails almost exclusively 

 in coal mines, is a mixture of light carbureted hydro- 

 gen and atmospheric air, which explodes with tre- 

 mendous violence whenever it comes in contact with 

 flame. The injuries which formerly occurred so 

 frequently, both to the machinery and to tne lives of 



miners, arising from the fire-damp, are now almost 

 completely obviated by the fine invention of Sir 

 Humphrey Davy, the safety-lamp. It consists of a 

 cylinder of wire gauze, about four inches in diameter 

 and one foot in length, having a double top, se- 

 curely fastened by doubling over to a brass rim, 

 which screws on to the lamp itself below. The whole 

 of the wire gauze is protected, and rendered con- 

 venient for carrying, by a triangle wire frame and a 

 ring at the top. The wire gauze is made either of 

 ron or copper, the wire being at least one-thirtieth 

 of an inch in diameter, and woven together so as to 

 ,eave 625 apertures in a square inch. The body of 

 the lamp is of riveted copper, or of massy cast brass 

 or cast iron, the screws fitting so completely as to 

 eave no aperture into the body of the lamp. When 

 the lamp is lighted, it affords the miner all the light 

 which he requires, and renders him perfectly secure, 

 even though entirely enveloped with the explosive 

 mixture, which, with an ordinary light, would im- 

 mediately prove fatal. The first eflect of the fire- 

 damp atmosphere is to increase the length and size, 

 of the flame. When the carbureted hydrogen forms 

 as much as one-twelfth of the volume of the air, 

 ;he gauze cylinder becomes filled with a feeble blue 

 Same, but the flame of the wick appears burning 

 brightly within the blue flame, and the light of the 

 wick augments until the inflammable gas increases 

 to one-sixth or one-fifth, when it is lost in the flame of 

 ;he fire-damp, which now fills the cylinder with a pret- 

 ,y strong light. As long as this explosive mixture 

 of gas exists in contact with the lamp, so long 

 it will give light ; and when it is extinguished, 

 which happens when the foul air constitutes as much 

 as one-third of the volume of the atmosphere, the air 

 is no longer proper for respiration ; for though animal 

 life will continue when flame is extinguished, yet it is 

 always with suffering. A coil of platinum wire being 

 fixed above the wick of the lamp, witliin the gauze 

 cylinder, the metal continues to glow long after the 

 lamp is extinguished, and affords a sufficient light to 

 enable the miner to make his escape. The effect of 

 the safety-lamp is supposed to depend on the cooling 

 agency of the wire gauze, exerted on the portion of 

 gas burning within the cylinder. Hence a lamp may 

 be secure where there is no current of an explosive 

 mixture to occasion its being strongly heated, and yet 

 not safe when the current passes through it with great 

 rapidity. But any atmosphere, however explosive, 

 may be rendered harmless by increasing the cooling 

 surface, which may be done either by diminishing the 

 size of the apertures, or by increasing their depth, 

 both of which are perfectly within the power of the 

 manufacturer of the wire gauze. 



DAN (pe'rhaps from dominus like the Spanish don, 

 and the Italian donna, from domino) ; the old term of 

 honour for men, as we now say master. It is used 

 by Shakspeare, Spenser, and Prior. 



DAN (Hebrew; meaning judymenf) ; one of the 

 twelve patriarchs, the fifth son of Jacob. The Dan- 

 ites were one of the twelve tribes of Israel. 



DINAE, in fabulous history, daughter of Acri- 

 sius, king of Argos. She was shut up by her father 

 in a brazen tower, because an oracle had declared, 

 that a son of his daughter should put him to death. 

 But Jupiter, inflamea with passion for the clianuiiiff 

 virgin, transformed himself into a golden shower, and 

 descended through the apertures of the roof into her 

 embraces. When Acrisius discovered that his daugh- 

 ter had become a mother, he exposed her, with her 

 child, in a frail boat, to the violence of the waves. 

 But the sea-goddesses, anxious for the preservation 

 of the son of Jove, commanded the billows to waft 

 the skiff' safely to Seriphos, one of the Cyclades. 

 PolydecteSj or rather Dictys, the governor of the 



