HACHETTE, JEAN NICOLAS PIERRE, was born at Mezieres, Slay 6, 1769. He began his studies at Mezieres, where Monge then aeld a professorship. At the age of tweuty-threo he was the compe titor in the contours for a professorship of hydrography at Collioure.
Some memoirs on mathematical subjects which he addressed to Menge, then minister of marine, procured Lim to be called to Paris, from whence he was sent to fill a professorship at Mezieres, and at the end of 1794 was appointed to the Ecole Polytechnique, at its establishment. In this post ho continued till the accession of Louis XVIII., by whose feeble and fanatical government be was, in 1816, deprived of his professorship, at the same time that Moog° was expelled from the Institute. The government above-mentioned refused to sanction his admission to the Academy of Sciences; nor was it till after the Revolution of 1830 that the fellow-labourer of Menge, the instructor of Poisson, Frcsuel, Arago, and of more than two thousand of the best qualified public officers in France, was per mitted to sit among his former pupils at the Palais de l'Institut.
M. Hachette died in January 1834, at the time when the cholera was raging in Paris, though not of that disorder. Independently of his public services, he obtained the respect of the whole commuuity foe his private worth; and the writer of this article, who eujoyed his acquaintance and corroapondeuce during the last years of his life, can bear testimony to the openness, simplicity, and benevolence of his character, which, though not very common to such an extent among his countrymen, are, of all other qualities, those which most assist and least require their well-known address and manners.
The greater part of the life of M. Hachette was devoted to the development of the descriptive geometry of Menge, and its applica tion iu the arts of life, particularly in the description and oonstruction of machinery. The attention which was paid to this subject from the opening of the Polytechnic School was one main cause of the improvemeut which took place iu Franco as to all matters connected with construction. There is no question that since the Revolution of 1789 that country has made very rapid progress in all that relates to the arts which depend upon geometry. The genius of Mooge and the foresight of those who founded the Polytechnic School were the primary causes of this improvement: 3I. Hachette was the most dis tinguished among those whose efforts filled up the details, dissemi nated the knowledge of the whole, and kept alive the impulse which the new state of things had given. Menge left the details of the descriptive geometry for the most part to Hachette, who made the first special application, and particularly to the construction of machinery. His works on descriptive geometry (that of Menge being comparatively elementary) and on machinery are still in high repute.
The works of 31. Hachette ars :—' Programmes d'un Coura de Physique, 1309; an extension of a work previously written by Menge and Hachette in 1805. Correspondence sur l'Ecole Polytechnique,' 1803-15, a work edited by M. Hachette, and containing many memoirs
by himself, some of great interest. Epures, or Collection of Drawings exemplifying the processes of Descriptive Geometry,' 1817. ' Elcknens de GeoneStrio h trois dimensions,' 1817, in two parts, geometrical and algebraical. This work is remarkable as containing various theorems, demonstrated geometrically, which had not been previously obtained without algebra. 'First and Second Supplements to the Descriptive Geometry of Menge,' 1812 and 1818. Traitd Effimentaire dos Machines,' first edition about 1820, and three others since published. M. Hachette had previously, in 1808, taken a share in the work of MM. Lanz and Bdtancour, 'Sur la Composition des Machines.' 'G6ometrie Descriptive,' 1822. Various memoirs in the 'Annalea d'Agriculture ;" Societd Royale, atc., d'Agriculture ; "Soci6tsi d'En couragement,' &c.; 'Journal de PEcole Poly technique,' &c., &c. HACKERT, PHILIPP, a celebrated German landscape-painter, was born at Prenzlau in Prussia in 1737. His father was a portrait-painter and a native of Berlin, where Heckert spent some time with an uncle who was a decorative painter. lie acquired his chief knowledge of painting however by copying good pictures; and he derived great also from the acquaintance of be Sueur, the director of the Berlin Academy, and of Sailer. In 1765 be visited Paris, and in 176S he went with his brother Johann to Italy. They spent some time in Rome sketching and painting the scenery about Albano and Tivoli: many of their works were purchased by Lord Exeter. Philipps first works of Importance however were the six large pictures of the Russian naval victory of Tscheme, and the burning of the Turkish fleet, by Count Orlow in 1770, painted for the Empress Qitherioo of Russia. Count Orlow, to whom the works were sent at Leghorn, was upon the whole highly gratified by their successful accomplishment, but he was dissatisfied with the representation of the explosion of a ship in the picture of the burning of the fleet ; and in order to give the artist a proper impression of such a catastrophe, be ordered, with a spirit worthy of ao autocrat, one of the frigates of hie fleet, au old vessel, to be blown up In the presence of Heckert in the roads of Leghorn. Ho was well satisfied with the results of his experiment, for Heckert greatly improved the picture. These works, with six other similar subjects, are now at St. Petersburg. In 1772, the year in which the first mentioned pictures were completed, Johann Ilackert died at Bath, aged only twenty-nine : be came to England with some pictures which had been ordered by English travellers in Rome. In the meanwhile two other brothers, Wilhelm and Karl, joined Philipp in Rome; but Wilhelm went shortly afterwards to St. Petersburg, and died there in 1789, aged only thirty-two ; and Karl settled in Switzerland. Philipp accordingly in 1773 sent for his youngest brother Georg, who was an engraver at Berlin, and they lived together from that time until the death of Georg at Florence in 1805.