URAYTON DREDGING. 



729 



feels fine and rather meagre. It soils more or less, 

 and writes ; hence its use as a marking or drawing 

 material. The best kind comes from Italy, Spain, 

 and France. 



DRAYTON, WILLIAM HENRY, a statesman of the 

 American revolution, and an able political writer, was 

 born in South Carolina, in September, 1742. In 

 1753, he went to England, and was placed in West- 

 minster school ; thence he removed, in 1761, to Ox- 

 ford, where he continued nearly three years, when 

 he returned to South Carolina. In 1771 he was ap- 

 pointed, by the British government, privy councillor 

 lor the province, and became conspicuous by his de- 

 fence of the rights of his country against the encroach- 

 ments and irregularities of the crown officers and 

 judges. In 1774, he accepted the office of an assist- 

 ant judge of the province. When the continental 

 congress was about to sit at Philadelphia, he wrote 

 and published a pamphlet under the signature of 

 Freeman, a production, of which Ramsay, in his 

 History of South Carolina, observes, that " it sub- 

 stantially chalked out the line of conduct adopted by 

 the congress." The lieutenant-governor suspended 

 him from his place in the king's council, in conse- 

 quence of his representation of American grievances, 

 and the " bill of American rights," which he sub- 

 mitted to the congress in his pamphlet. As soon as 

 the revolution began, he became an efficient leader, 

 and, in 1775, was chosen president of the provincial 

 congress. In March of the next year, he was elected 

 chief justice of the colony, in which character he 

 delivered to the grand jury political charges of the 

 most energetic character. He published, besides, 

 a pamphlet, refuting the suggestions in favour of 

 lord Howe's plan of a reconciliation with the mother 

 country. Independence unqualified independence 

 was his constant advice. In the year 1777, Mr 

 Drayton was invested with full powers, as president 

 of South Carolina, and, early hi the following year, 

 was elected a delegate to the continental congress. 

 In this body he took a prominent part. His speeches 

 and writings against the propositions of the three 

 British commissioners were particularly celebrated. 

 The congress employed him on various important 

 missions. The censure which he pronounced upon 

 major-general Cliarles Lee's conduct at the battle oJ 

 Monmouth, caused that officer to challenge him. 

 The reasons which he assigned for declining the duel 

 are such as become a true patriot and honourable 

 man. 



Mr Drayton continued in congress until Septem- 

 ber, 1779, when he died suddenly at Philadelphia, 

 in the thirty-sixth year of his age. He left behinc 

 a considerable body of historical materials, which his 

 only son, John Drayton, revised and digested, anc 

 published at Charleston, in 1821, in two octavo 

 volumes, under the title of Memoirs of the American 

 Revolution, from its Commencement to the Year 

 1776, inclusive, as relating to the State of South 

 Carolina, and occasionally referring to the States o 

 North Carolina and Georgia. The work is mucl 

 esteemed. 



DREBBELL, CORNELIUS ; a natural philosopher 

 and philosophical instrument-maker, was born a 

 Alkmaer, in North Holland, in 1572. He possesse( 

 a great spirit of observation, and a sufficient fortun 

 to enable him to perform his mechanical and optica 

 experiments. He soon became so famous, that the 

 emperor of Germany, Ferdinand II., intrusted to him 

 the instruction of his sons, and appointed him impe 

 rial councillor. In the troubles of 1620, he wa 

 made prisoner by the troops of Frederic V., electo 

 palatine, and plundered of his property. He wa 

 liberated by the interference of James I. of England 

 the fether-in-law of Frederic, who delighted in th 



Conversation of learned men, and to whose court he 

 epaired. From this time he lived in London, con- 

 tantly occupied in scientific pursuits, and died there 

 n 1634. The accounts which his contemporaries 

 ive of his experiments are not to be trusted, on ac- 

 ount of the ignorance and credulity of the time. It 

 s certain that, in mechanics and optics,, he possessed 

 Teat knowledge for the age. He invented several 

 uithematical instruments, and the thermometer 

 about 1630), which Halley, Fahrenheit, and Reau- 

 nur afterward brought to perfection. The invention 

 f telescopes, which has been also attributed to him. 

 trobably belongs to Zachariah Janson (1590). His 

 rractatus de Natura Elententorum et Quinta Essentia 

 ublished by Joh. Ernst Burggrav, Ley den, 1608, 

 assed through several editions. His Epistola d 

 Wachina Astronomica perpetuo mobili, was published 

 at Leyden, 1620, by Joach. Morsius. A letter in 

 ~erman, to the emperor Rodolph II., in which he 

 lescribes an instrument of his called Machina musica 

 jerpetuo mobilis, is contained in Harsdorffer's Delicice 

 ihysico-mathematicce, second volume. 



DREDGING is commonly applied to the operation 

 >f removing mud, silt, and other depositions, from 

 he bottom of harbours, canals, rivers, docks, &c. 

 The process of silting may be readily conceived, 

 when it is considered that 'every rill of water carries 

 with it a quantity, however minute, of earthy parti- 

 les, and that these rills are so many tributaries to 

 the brooks and rivulets felling into the great streams 

 which form the drainage of the vast valleys through 

 which they flow, finally carrying their waters to the 

 . The beds of all large rivers, more particularly 

 those which pass along comparatively flat or alluvial 

 soils, are much encumbered in their channels by 

 banks of sand and small gravel, while on their mar- 

 gins are found the finer or more minute depositions 

 of silt and mud. Large streams, from the great body 

 of water which they bring, and from the greater 

 strength of their currents, will be always able to 

 make a passage ; but narrow and winding rivers, 

 with slowly-flowing waters, are often materially in- 

 jured by the depositions. To such a degree has this 

 been experienced at Sandwich, hi Kent, tliat that 

 ancient seaport is left almost in the state of an inland 

 town ; and the port of Little Hampton, on the coast 

 of Sussex, which was a harbour for the largest vessels 

 two centuries since, at present admits only small 

 colliers, and even those with difficulty, at liigh spring 

 tides. The rivers of Holland, and those flowing 

 through the plains of Italy, are likewise thus affected ; 

 and, according to the impurity of the waters, the 

 entrances of docks and harbours, canals, basins, &c., 

 are more or less silted up, and require to be cleansed 

 or dredged. The late Mr Rennie reported that 

 400,000 tons of mud were annually discharged into 

 the Thames from the sewers of London. The innu- 

 merable shoals between the Nore and the Downs 

 amply prove that this calculation is not exaggerated. 

 The most simple mode of dredging, and probably 

 the one originally adopted for removing the inequali- 

 ties from the bottom of rivers and harbours, is the 

 spoon dredging-boat. An apparatus of this de- 

 scription was used for dredging the liarbour of Leg- 

 horn so far back as 1690, the expense of which 

 was fifteen paoli (about eight shillings sterling) the 

 boat load, of the sire of a small river barge. But 

 Cornelius Meyer, a Dutch engineer in the employ of 

 Cosmo III., grand duke of Tuscany, built, at Leg- 

 horn, a dredging-boat, after the fashion of those in 

 common use in Holland at that period. The expense 

 of the construction of this boat is stated to have been 

 about 25, and the cost of dredging a boat load five 

 paoli, being only one-third of the Italian apparatus. 

 The spoon dredging-boat has been long, and is, in- 



