L A D L A D 199 literary activity. He died suddenly on November 26, 1791. His numerous works include Contes Fhilosophiques et Moraux (1765), characterized by Sabatier as " less agree able than those of Marmontel, but more moral, more varied, and showing a keener sensibility ; Les deux ages du Gout et da Genie sous Louis XIV. et sous Louis AT., a parallel and contrast, in which the decision is given in favour of the latter ; L 1 Espagne litteraire (1774) ; Eloge de Voltaire (1779) and Eloge de Montaigne (1781). LADOGA, formerly NEVO, a lake of northern Russia, situated between 59 56 and 61 46 N. lat,, and 29 53 and 32 50 E. long., surrounded by the governments of St Petersburg, Olonetz, ancl Wiborg. It has the form of a quadrilateral, elongated from north-west to south-east. Its eastern and southern shores are flat and marshy, whilst the north-western margin is craggy and fringed by numerous small rocky islands, the largest of which are Valaam and Konevetz, and which occupy altogether an area of 223 square miles. Lake Ladoga is 7000 square miles in area, that is, thirty-one times as large as the Lake of Geneva ; but, its depth being less, it contains only nineteen times as much water as the great lake of Switzerland. The greatest depth, 244 yards, is in a cavity situated in the north-western part of the lake, the average depth not exeeediug 100 yards. The level of Lake Ladoga is 55 feet above the Gulf of Finland, but it rises and falls about 7 feet according to atmospherical conditions. The western and eastern shores consist of boulder clay, as well as a narrow strip on the southern shore, south of which runs a ridge of crags of Silurian sandstones ; the hills of the north western shore afford a variety of granites and crystalline slates of the Laurentian system, whilst the Valaam island is made up of a rock which Russian geologists describe as orthoclastic hypersthenite. The granite and marble of Serdobol, and the sandstone of Poutilovo, are much used for buildings at St Petersburg ; copper and tin from the Pitkaranda mine are exported. No less than sixty rivers enter Lake Ladoga, pouring into it the waters of number less smaller lakes which lie at higher levels around it. The Volkhov, which conveys the waters of Lake Ilmen, is the largest ; Lake Onega discharges its waters by the Svir ; and the Saima system of lakes of eastern Finland contributes the Wuoxen and Taipala rivers ; the Syass brings the waters from the smaller lakes and marshes of the Valdai plateau. Lake Ladoga discharges its surplus water by means of the Neva, which flows from its south western corner into the Gulf of Finland, rolling down its broad channel 104,000 cubic feet of water per second. The water of Lake Ladoga is very pure and cold ; in May its temperature on the surface does not exceed 36 Fahr., and even in August it roiches only 50 and 53, the average yearly temperature of the air at Valaam being 36 8. The lake begins to freeze in October, but it is only about the end of December that it is frozen in its deeper parts ; and it remains under the ice covering until the end of March, whilst wide icefields continue to float in the middle of the lake until they are broken up by gales and scattered on the shores. Only a small part of the Ladoga ice is discharged by the Neva ; but it is enough to produce in the middle of June a return of cold in the northern capital. The thickness of the ice does not exceed 3 or 4 feet ; but during the alternations of cold and warm weather, with strong gales, in winter, heaps of ice, 70 and 80 feet high, are raised on the banks and on the icefields. The water of the lake is in continuous rotatory motion, being carried along the western shore from north to south, and along the eastern from south to north. The vegetation on the shores is poor ; immense forests, which formerly covered- them, are now mostly destroyed ; but the fauna of the lake is somewhat rrch ; a species of seal which inhabits its waters, as well as several arctic species of crustaceans, recall its former connexion with Uie Arctic Ocean. The great variety of sweet water Diatomacese, which are found in the ooze of the deepest parts of the lake has also an arctic character. Fishing is very extensively carried on. Navi gation on the lake, which is practicable for only one hundred and eighty days in the year, is rather difficult owing to fogs and gales, which are often accompanied, even in April and September, with snow storms. The prevailing winds are north-west and south-west; north east winds cause the water to rise in the south-western part of the lake, sometimes from 3 to 5 feet. A pheno menon very similar to the seiches of the Lake of Geneva is observed in connexion with the rise and fall of the barometer. Steamers ply regularly in two directions from St Petersburg to the monasteries of Konevetz and Valaam, and to the mouth of the Svir, whence they go up that river to Lake Onega and Petrozavodsk ; and no less than from 600 to 800 small vessels transport timber, fire wood, planks, iron, kaolin, granite, marble, fish, hay, and various small wares from the northern shore to Schliissel- burg, and thence to St Petersburg. The rivers Volkhov, Syass, and Svir being parts of the three great systems of canals which unite the upper Volga with the Gulf of Fin land, and the navigation on Lake Ladoga being too danger ous for small craft, three canals with an aggregate length of 70 miles were dug along the southern shore of Lake Ladoga, uniting the mouths of these three rivers with the Neva at Schliisselburg ; thousands of vessels pass yearly along them on their way to St Petersburg. The popula tion on the shores of the lake is sparse, and the towns Schliisselburg, with 6000 inhabitants, New Ladoga (4500), Kexholm (1000), and Serdobol (800) are poor; many small villages are situated on the southern, north-eastern, and western shores, but the total population of the shores of Lake Ladoga does not exceed 35,000. The monasteries of Valaam, founded in 960, on the island of same name, and Konevskiy, on the Konevetz island, founded in 1393, are highly venerated, and are visited every year by many thousands of pilgrims. LADRONE OR MARIANA ISLANDS, a chain of fif teen islands in the North Pacific Ocean, situated to the north of the Carolines, and between 13 ancl 21 N. lat., and 144 and 146 E. long. The name Islas de los Ladrones, or " Islands of the Thieves," was given them by the ship s crew of Magellan on account of the thieving propensity of the inhabitants. Magellan himself styled them Islas de las Velas Latinas, or "Islands of the Lateen Sails." San Lazarus archipelago, Jardines, and Prazeres are among the names applied to them by later navigators. They received their present recognized official appellation "Las Marianas" in 1668 in honour of Maria Anna of Austria, widow of king Philip IV. of Spain, and they still form a Spanish colony under the general government of the Philippines. A broad channel divides the Ladrones into two groups, containing a total area of about 417 square miles. The northern group (Gani) consists of ten islands, now unin habited ; live islands, of which four are inhabited, form the southern group, viz., Guahan (Guam, Spanish Guajan, the San Juan of old Spanish charts), Rota, Aguigan, Tinian, ancl Saypan. On Guahan, the largest and southern most of the group, is the only town in the colony, San Ignacio de Agafia, and the fortified harbour of Uniata. The general surface of the southern islands is far inferior in elevation to that of the northern group, which is mountainous, though the altitudes do not exceed 2600 to 2700 feet. The predominant rock in the southern group is madrcporic limestone, but in some instances, and especially at Guahan, volcanic formations occur. The northern
