DAVOUST DAY. 



605 



harn in 1770, at Annoux, in the former province of 

 Burgundy. He was of a noble family, and studied 

 at the same time with Bonaparte, in the military 

 school at Brienne. He distinguished himself under 

 Dumouriez, in the battles of Jemappe -and Neenvin- 

 den. When Dumouriez, after the battle of Neerwin- 

 den, treated with Coburg, Davoust conceived the 

 bold design of seizing the former in the midst of his 

 army, and nearly succeeded in the attempt. In June, 

 1793, he was made general ; but the decree, which 

 remtived the ex-nobles from the service, deprived 

 him of his command. The ninth Thermidor restored 

 him to the army. He was present at the siege of 

 Luxembourg, and afterwards on the Rhine, under 

 Pichegru. He was taken prisoner in Manheim, but 

 was soon exchanged, and distinguished himself in 

 1797, at the passage of the Rhine, by his prudence 

 and courage. In the Italian campaigns under Bona- 

 parte, he became zealously attached to that general. 

 He accompanied him to Egypt, where he distin- 

 guished himself by his intrepidity. It was he who, 

 after the battle of Aboukir, attacked and conquered 

 the village. He embarked for France from Alex- 

 andria, with Desaix, after the convention of El-Arish. 

 They were captured by a British frigate, near the 

 Hieres. Bonaparte afterwards gave him the chief 

 command of the cavalry in the army of Italy. After 

 the battle of Marengo, he was made chief of the. 

 grenadiers of the consular guard, which, from this 

 battle, was called the granite columns. When Na- 

 poleon ascended the throne (1804), he created Da- 

 voust marshal of the empire, grand cross of the le- 

 gion of honour, and colonel-general of the imperial 

 guard of grenadiers. In the campaign of 1805, he 

 showed himself worthy of his appointment, particu- 

 larly at the battle of Austerlitz, where he command- 

 ed the right whig of the army. In 1806, he marched 

 at the head of his corps into Saxony, and, at Auer- 

 staedt, where he commanded the right wing, con- 

 tributed so much to the success of the day, by 

 his skilful manoeuvres, that Napoleon created him 

 duke of Auerstaedt. After the peace of Tilsit, he 

 was made commander-in-chief of the army of the 

 Rhine. In the war of 1809 against Austria, his 

 marches through the Upper Palatinate, and the 

 engagement at Ratisbon, were hazardous enter- 

 prises. He had an important share in the vic- 

 tory at Eckmuehl. In the battle of Aspern, only 

 one of his four divisions was engaged, the great- 

 est part of which, with its general, St Hilaire, per- 

 ished on the left bank of the Danube. In the 

 battle of Wagram, Davoust commanded the right 

 wing, to the manoeuvres of which the retreat of the 

 Austrians was mainly owing. After the peace, Na- 

 poleon created him prince ot Eckmuehl, and, in 1811, 

 appointed hinf governor-general of the Hanseatic 

 departments. In Russia (1812), his division was 

 defeated on the retreat from Moscow. In 1813, he 

 commanded 50,000 men, French and Danes, in 

 Mecklenburg ; but was soon besieged in Hamburg, 

 which suffered, at that time, very severely. Da- 

 voust was in a critical situation, and could support his 

 army only at the expense of the citizens. He lost, 

 during the siege, as many as 11,000 men. In 1814, 

 he published, at Paris, a defence of himself from the 

 charge of cruelty towards Hamburg 1 . On the return 

 of Napoleon to Paris, in March, 1815, he was made 

 minister of war. When the allies advanced to 

 Paris, after the battle of Waterloo, Davoust, as com- 

 mander-in-chief, concluded a military convention 

 with Bluecher and Wellington, in compliance with 

 which he led the French army beyond the Loire. He 

 submitted to Louis XVIII., exhorting the army to 

 follow his example, and, in obedience to an order of 

 the king, surrendered the command to marshal Mac- 



donald. For this service, he was afterwards em- 

 ployed by the court. Davoust died June 1, 1823. 

 Firmness of character, personal bravery, and a mili- 

 tary rigour often approaching to cruelty, were his 

 characteristics. Davoust left two daughters, and a 

 son of thirty years of age, who inherited the rank of 

 a peer. 



DAVY> SIR HUMPHREY, bart., one of the most 

 distinguished chemists of the age, was born at Pen- 

 zance (Cornwall), Dec. 17, 1779. After having re- 

 ceived the rudiments of a classical education, he 

 was placed with a surgeon and apothecary, who pro- 

 nounced him an " idle and incorrigible boy." He 

 liad, however, already distinguished himself at school, 

 and a taste for chemistry, which he displayed in some 

 experiments on the air contained in sea-weed, at- 

 tracted the attention of Mr Gilbert (now president 

 of the royal society), and doctor Beddoes. The 

 latter, who had just established a pneumatical insti- 

 tution at Bristol, offered him the place of assistant 

 in his laboratory. Here Davy discovered the re- 

 spirability and exhilarating effect of the nitrous 

 oxide. He published the results of his experi- 

 ments, under the title of Chemical and Philosophical 

 Researches, &c. (London, 1800). This work im- 

 niediately obtained him the place of professor of 

 chemistry in the royal institution, at the age of 

 twenty-two. In 1803, he was chosen a member of 

 the royal society. His lectures at the royal insti- 

 tution were attended by crowded and brilliant audi- 

 ences, attracted by the novelty and variety of his ex- 

 periments, the eloquence of his manner, and the 

 clearness of his exposition. His discoveries with 

 the galvanic battery, his decomposition of the earths 

 and alkalies, and ascertaining their metallic bases, 

 his demonstration of the simple nature of the oxy 

 muriatic acid (to which he gave the name of chlo- 

 rine), &c., obtained him an extensive reputation ; 

 and, in 1810, he received the prize of the French in- 

 stitute. In 1814, he was elected a corresponding 

 member of that body. Having been elected -profes- 

 sor of chemistry to the board of agriculture, he de- 

 livered lectures on agricultural chemistry during ten 

 successive years, and, in 1813, published his valu- 

 able Elements of Agricultural Chemistry. His next 

 discovery was of no less importance to humanity than 

 his former researches liad been valuable to science. 

 The numerous accidents arising from fire-damp in 

 mines led him to enter upon a series of experiments 

 on the nature of the explosive gas, the result of 

 which was the invention of his safety lamp. (See 

 Damps.) In 1818 and 1819, he visited Italy, and 

 made some unsuccessful attempts to unroll the Her- 

 culanean manuscripts. In 1820, he succeeded Sir J. 

 Banks as president of the royal society. In 1824, 

 he visited Norway for the purpose of making some 

 scientific investigations. On this voyage, he proved 

 the efficacy of his plan for preserving the copper of 

 ships, by covering it in part with a certain quantity 

 of iron. At the same time the trigonometrical 

 measurements of Denmark and Hanover were con- 

 nected, under his direction, by chronometrical ob- 

 servations, with the measurements in England. This 

 distinguished philosopher died May 29, 1829, at 

 Geneva, whither he liad gone for the benefit of his 

 health. Besides the works already mentioned, the 

 most important are Electro-Chemical Researches ; 

 Elements of Chemical Philosophy (vol. 1., 1802) ; 

 Bakerian Lectures (1807 1811) ; Researches on 

 the Oxymuriatic Acid (1810)-; On the Fire-Damp 

 (1816). He also contributed some valuable papers 

 to the Philosophical Transactions, and the journals 

 of Nicholson and Tilloch. 



DAY, properly speaking, is the time of a revolu- 

 tion of the earth round its axis (sidereal day, see 



