596 



DAPHXIS DARDANELLES. 



evaporate in acrid acidjapours ; and are sparingly 

 soluble in cold, and but moderately so in boiling 

 water. 



DAPHNIS, in fabulous history ; the son of Mer- 

 cury by a nymph, educated amon;? the nymphs, and 

 celebrated in the Sicilian traditions as the author of 

 Bucolic poetry, and also as a performer on the shep- 

 herd's jiijic. lit- pastured liis kine upon mount JEtnn. 

 1'he nymjili liclienais, who loved the youth, threat- 

 IK .1 liiiu witli blindness if he should love another ; 

 init, lx'iii intoxicated with wine by the daughter of 

 ,i Sicilian prince, lie forgot her warnings, and thus 

 bronirht iijon himself the threatened punishment, 

 say tliat he dietl of grief; others, tliat the 

 nymph transformed him into a stone. All the nymphs 

 bewailed his death, and Mercury raised him to the 

 heavens. On the spot where he died flowed a foun- 

 tain, at which the Sicilians afterwards performed 

 yearly sacrifices. 



DARCET, JOHN ; an eminent French physician 

 and chemist, born in 1725, at Douazit, in Guienne. 

 He preferred the study of medicine to that of the law ; 

 in consequence of wliich, having been discarded by 

 his father, he was obliged to teach Lathi for his sup- 

 port, while pursuing 1 his studies at Bourdeaux. He 

 accompanied the celebrated Montesquieu to Paris in 

 1742, and remained with him till his death as a lite- 

 rary assistant. He afterwards devoted himself to 

 chemistry, and went to Germany, in 1757, with the 

 count de Lauraguais, and visited the mines of the 

 1 1 am, in Hanover. On the restoration of peace, 

 they applied themselves to technical chemistry, espe- 

 cially to the improvement of the manufacture of por- 

 celain. Darcet made many experiments with this 

 view, of which he drew up an account in several me- 

 moirs presented to the academy of sciences in 1766 

 and 1768. He tried the effect of fire on the various 

 kinds of earths, and demonstrated the combustibility 

 of the diamond ; on which subjects he presented me- 

 moirs to the academy in 1770. In 1774, he travelled 

 over the Pyrenees, to study the geology of those 

 mountains, on which he delivered a discourse at the 

 college of France, wliich was published in 1776. On 

 the death of Macquer, he succeeded him as a member 

 of the academy of sciences, and director of the ma- 

 nufactory of Sevres. He was afterwards appointed 

 inspector- general of the assay of coin, and inspector 

 of the Gobelin manufactory. He made several im- 

 portant chemical discoveries, and contributed much 

 to the present improved state of the science. During 

 the reign of terror, his life was preserved by Fourcroy, 

 who procured the obliteration of his name from a list 

 of persons destined by Robespierre to destruction. 

 He died in 1801, at which period he was a member 

 of the institute, and of the conservative senate. 



DARCET, JOHN PETER JOSEPH, an excellent prac- 

 tical chemist, born at Paris in 1787, has very success- 

 fully applied the discoveries in his science to the pro- 

 motion of French industry. His father, who died in 

 1801 . in the- office of director-general of the porcelain 

 manufactory at Sevres, also distinguished himself as 

 a practical chemist ; and his grandfather was the ce- 

 lebrated Rouelle, the restorer of chemistry in France. 

 Darcet entered early upon his career, after liaving 

 laid the foundation of his eminence by the study of 

 mathematics and natural philosophy. In his twenty- 

 fourth year he was made assayer of the mint ; and, 

 after introducing, among other discoveries, a new 

 process for the preparation of powder on a large 

 . scale, he made experiments on the addition of sea-salt 

 in the manufacture, and essentially unproved the pre- 

 paration of the hydrate of the protoxide of barytes. 

 These experiments led to new discoveries respecting 

 elective affinity ; but the decomposition of sea-salt 

 was of the greatest importance, and eventually led 



to the establishment of the manufacture of artificial 

 natron (soda). Among his other discoveries, we may 

 notice the extraction of alkali from chestnuts, the 

 preparation of sugar from the same material, andtlie 

 extraction of jelly from bones by means of an acid. 

 The hospital of Loins at Paris is 'indebted to him for 

 the excellent footing on which he put its baths and 

 clumneys, and for the process wliich lie introduced for 

 bleaching the linen of the hospitals. He ai <> made 

 another discovery of great importance, whereby Jie 

 obtained the prize of 3000 francs, which Ka\ rio" lia.i 

 provided for the discovery of the means of protection 

 against the fine dust of quicksilver, which liad Ix-en 

 so unhealthy to the gilders. Darcet's discovery com- 

 pletely attained the object, and this brand i of French 

 industry lias since increased greatly in importance. 

 He lias also offered a plan for preserving the health 

 of those concerned in the manufacture of Prussian 

 blue. 



DARDANELLES are the four strong castles built 

 on the European and Asiatic coasts of the Hellespont, 

 opposite to each other, and commanding that strait, 

 which is about twelve leagues long, and called, from 

 them, the strait of the Dardanelles, so tliat they are 

 looked upon as the key of Constantinople. Their 

 name is probably derived from the old city of Dar- 

 danum. The entrance to the Hellespont is defended 

 by two castles, which are called the new castles, be- 

 cause they were built (subsequently to the two others, 

 called the old castles), in the middle of the seventeenth 

 century, under Mohammed IV., to afford protection 

 to the Turkish fleet against the Venetians. The dis- 

 tance of one from the other is about two miles and a 

 quarter. Four hours' sail farther to the north lie the 

 old castles, built by Mohammed II., immediately after 

 the conquest or Constantinople, which are not more 

 than 1500 yards apart. Farther on still the channel 

 becomes narrower, and, at an hour and a half's sail 

 from the old castles, two promontories appear sud- 

 denly, about 750 yards distant one from the other, 

 and form that strait rendered famous by Leander's 

 nightly visit to Hero, by Xerxes' bridge, and by Soly- 

 man's passage upon a bare raft. This is not provided 

 with fortifications. It Ie38s into the sea of Marmora, 

 at the north-eastern end of which lies Constantinople, 

 the capital of the Ottoman empire, upon another 

 channel, which connects the Black sea with t>e sea 

 of Marmora. The late lord Byron, in the month of 

 March, 1810, swam from the castle of Sestos, in Eu- 

 rope, to the fort of Abydos, hi Asia, in company with 

 lieutenant Ekenhead, an English naval officer, and 

 mentions the feat in his works with evident satisfac- 

 tion. The same feat has been repeatedly performed 

 in modern times. The negligent Turks, confiding ir. 

 the celebrity of the castles of the Dardanelles, have 

 taken so little care to keep them hi a state of defence, 

 that in 1770 they wtoe completely hi ruins, and upon 

 the Asiatic side there* was but a single battery stand- 

 ing, and that half filled with rubbish. On the 20th 

 of July of that year, when the squadron of the Rus- 

 sian admiral Elphinstone, consisting of three ships of 

 the line and four frigates, in pursuit of two Turkish 

 ships of the line, appeared before the first castles, the 

 Turkish batteries, from want of ammunition, were 

 obliged to cease firing, after one general discharge of 

 their ordnance, and Elphinstone sailed by without re- 

 ceiving more than a single shot. But, the other ships 

 not following him, he contented himself with continu- 

 ing his course, not minding the Turkish batteries, and 

 cast anchor hi the channel. From hence he returned 

 to his fleet, notwithstanding a contrary wind, with 

 drums and trumpets sounding, as much to conceal his 

 own fear as to deride the weakness of the Ottomans. 

 Warned by this unexpected circumstance, the Porte 

 accepted the offer of baron de Tott (q. v.) to restore 



