Volume 3, Part 1, Slice 2 Part 35 (1/2)

BALTA, a town in the Russian government of Podolia, between the Dniester and the Bug, 131 m. by rail N.N.W. of Odessa. It carries on a large trade in cattle, horses and grain, and has two annual fairs, held at Whitsuntide and in June. A variety of industries, such as tallow-melting, soap-boiling, tile-making and brewing, are carried on. The Jews form a very considerable part of the population, which in 1867 numbered 14,528, and in 1897, 23,393.

Balta was in great part destroyed by the Russians in 1780.

BALTARD, LOUIS PIERRE (1764-1846), French architect and engraver, was born in Paris on the 9th of July 1764. He was originally a landscape painter, but in his travels through Italy was so much struck with the beauty of the Italian buildings, that he changed his profession and devoted himself to architecture. In his new occupation he achieved great success, and was selected to prepare the plans for some of the largest public edifices in Paris. His reputation, however, is chiefly based on his great skill in engraving. Among the best known of his plates are the drawings of Paris (_Paris et ses monuments_, 2 vols. fol., 1803), the engravings for Denon's _egypte_, the ill.u.s.trations of Napoleon's wars (_La Colonne de la grande armee_), and those contained in the series ent.i.tled the _Grand prix de l'architecture_, which for some time he carried on alone. He also gained distinction as an engraver of portraits. Baltard died in Paris on the 22nd of January 1846.

Two of his children were also architects. Of these the more important was VICTOR BALTARD (1805-1874), who was born in Paris on the 19th of June 1805.

In 1833 he gained the _prix de Rome_ at the ecole des beaux-arts for designing a military school. He was largely instrumental in introducing a regular scheme of fresco decoration by modern artists in the churches of Paris, to take the place of the heterogeneous collections of pictures of all kinds with which their walls had been promiscuously decorated. He built many additions to existing churches, and also the church of St Augustin, in which he united the structural values of stone and steel. His most popular achievement was, however, the building of the central market in Paris.

Victor Baltard also built the slaughter houses and the cattle market of La Villette. He died in Paris on the 13th of January 1874, after a life of great activity in his profession.

BALTIC SEA (Scand. and Ger. _Ostsee_; Russ. _Baltiyskoe More_), a sea extending between 54 and 66 N. lat., and 9 and 30 E. long., surrounded by the territories of Sweden, Russia, Germany and Denmark. Its greatest length is about 960 m.; greatest breadth about 400 m.; and length of coast-line, 5000 m.; the central axis runs approximately from south-west to north-east. The Baltic is connected with North Sea by the winding channel between the south of Scandinavia and the Cimbrian peninsula. This channel is usually included in the Baltic. The part of it west of a line joining the Skaw with Christiania fjord receives the name of Skagerrak; the part east of this line is called the Kattegat. At its southern end the Kattegat is blocked by the Danish islands, and it communicates with the Baltic proper by narrow channels called the Sound, the Great Belt and the Little Belt. The real physical boundary between the North Sea and the Baltic is formed by the plateau on which the islands Zealand, Funen and Laaland are situated, and its prolongation from the islands Falster and Moen to the coasts of Mecklenburg and Rugen.

East of this plateau the Baltic proper forms a series of hollows or troughs. The first, or Bornholm deep, lies east of the island of Bornholm, and is separated from the next, or Gotland deep, by the Middelbank. Beyond the Middelbank the Danziger Tiefe, an isolated depression, lies to the south-east, while to the northeast the Gotland basin, the largest and deepest of all, extends north-eastwards to the Gulf of Finland. Along the Swedish coast a deep channel runs northward from outside the island of oland; this is entirely cut off to the south and east by a bank which sweeps eastward and northward from near Karlskrona, and on which the island of Gotland stands, but it communicates at its northern end with the Gotland deep, and near the junction opposite Landsort is the deepest hole in the Baltic (420 metres = 230 fathoms).

An unbroken ridge, extending from Stockholm to Hango in Finland, separates the Baltic basin proper from the depression between Sweden and the land Isles, to which the name land Haf has been given. North of the land Haf a ridge defines the southern edge of another depression, the Bothnian Sea, which in turn is separated from the most northerly division, the Gulf of Bothnia, by a ridge across the narrow Quarken or Kvarken Strait. The Gotland deep may be said to extend directly into the Gulf of Finland, an arm of the Baltic, running eastwards for about 250 m., and separating Finland from Esthonia. Between Esthonia and Courland is the Gulf of Riga, a shallow inlet of roughly circular form, about 100 m. in diameter, and nowhere more than 27 fathoms deep.

According to recent computations the total area of the Baltic, including the Skagerrak and Kattegat, is 166,397 sq. m., and its volume 6907 cub. m., giving a mean depth of 36 fathoms, which is markedly less than that of any other arm of the sea of similar area.

In the deeper hollows in the south part of the Baltic the bottom consists almost invariably of either soft brown or grey mud or hard clay, while on the shallow banks and near the low coasts fine sand, of white, yellow or brown colour with small pebbles, is usually found.

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[Sidenote: Coasts--changes and character.]

At the time of the last great subsidence, in glacial times, an arm of the sea extended across Sweden, submerging a great part of the littoral up to the Gulf of Bothnia, and including the present lakes Vener, Hjelmar and Malar. During this period the waters of the northern Baltic were sufficiently salt for oysters to flourish. The subsequent upheaval restricted direct communication with the open sea to the Danish channels, and the Baltic waters became fresher: the oyster disappeared, but a number of cold salt-water fishes and crustaceans, and even seals, became acclimatized. It has been suggested that the presence of the remains of these animals indicates a communication to the north with the Arctic Ocean; but in view of the severe climatic conditions still prevailing at the time, this seems an unnecessary a.s.sumption. In the next stage of its history the Baltic is transformed by further elevation into a vast freshwater lake, the _Ancylus_ lake of G. de Geer (named from the remains of the mollusc _Ancylus fluviatilis_), which is supposed to have covered an area of about 220,000 sq. m., including the whole of the present Baltic area and a large part of Finland, with Lake Ladoga. Then followed a subsidence, which not only re-established communication through the Danish channels, but allowed the Baltic to become sufficiently salt for such forms as _Cardium edule_ and _Littorina littorea_. At this time the Gulf of Bothnia must have suffered greater depression than the Baltic proper, for the deposits of that epoch show a thickness of 100 metres (328 ft.) near Hernosand, but of only 25 metres (82 ft.) in the neighbourhood of Gotland. After this period of subsidence the process of elevation set in which gave the Baltic its present form and physical condition, and appears to be still in progress.

Dr R. Sieger has traced a series of isobasic lines, or lines of equal rate of elevation, for portions of Sweden and Finland; these indicate that the movement is now almost _nil_ along the axial lines of the Baltic and the Gulf of Finland, but increases in amplitude northwards to the Gulf of Bothnia and in the direction of the main ridge of the _ma.s.sif_ of southern Sweden. At Stockholm the rate of elevation is approximately 0.47 metre (= 1.54 ft.) in a century.

The coast of the Baltic is rocky only in the island-studded region at the head of the Baltic basin proper--a submerged lake-district--and the littoral generally is a typical morainic land, the work of the last great Baltic glacier. The southern margin of the Baltic is of peculiar interest.

From Schleswig eastwards to Lubeck Bay the coast is pierced by a number of narrow openings or _Fohrden_, the result of encroachment of the sea caused by subsidence. East of Lubeck, as far as the mouth of the Oder, these give place to _Bodden_, ramified openings studded with islands: the structure here resembles that of Scania in southern Sweden, a region once joined to both Denmark and Pomerania by an isthmus which was severed by tectonic movements. Beyond the Oder the coast-line is unbroken as far as the Gulf of Danzig. It is then cut into by the estuaries of the Vistula, the Pregel and the Memel. Here the westerly winds have full play, and the coast is rimmed by a continuous line of dunes, which cut off the two great lagoons of the _Frisches Haff_ and _Kurisches Haff_ by sandspits or _Nehrungen_.

The drainage area of the Baltic is relatively large. According to the measurements of Sir J. Murray it extends to 461,450 sq. sea m. ( = 611,700 sq. English m.) The largest river-basin included in it is that of the Neva in the east, and next in size come the Vistula and the Oder in the south.

The narrow parallel troughs, at right angles to the coast, which form the drainage-system of Sweden and western Finland, are a remarkable feature.

[Sidenote: Level.]

Levellings from Swinemunde show that the mean level of the surface of the Baltic at that point is 0.093 metres (= .305 ft.) below the surface of the North Sea at Amsterdam, and 0.066 metres ( = .216 ft.) below its level at Ostend. A line of levels from Swinemunde through Eger to the Adriatic showed the mean level of the surface of the Baltic to be 0.499 metres (1.6 ft.) above that of the Adriatic Sea. The mean level of the surface of the Baltic rises about 0.5 metres (1.6 ft.) from the coast of Holstein to Memel, probably as a result of the prevailing westerly winds; this mean difference is exceeded with strong westerly winds, and disappears or is reversed with easterly winds. The waves of the Baltic are usually short and irregular, often dangerous to navigation. Destructive waves, probably caused by distant earthquakes, called _Seebaren_ (cf. English ”bores”) have been recorded.

The range of the tides is about one foot at Copenhagen; within the Baltic proper ordinary tides are scarcely perceptible. There is, however, a distinctly marked annual rise and fall due to meteorological influences having a mean range of about 11.4 cm. (0.37 ft.), at Travemunde, and 13.9 cm. (0.46 ft.) at Swinemunde, the maximum occurring at the end of the summer rainy period in August.

[Sidenote: Circulation.]

The circulation of water in the Baltic proper must be considered apart from the circulation in the channels connecting it with the North Sea; and in this relation the plateau connecting the islands Falster and Moen with the coast of Mecklenburg and Rugen must be taken as the dividing line. In the great basins and hollows from Rugen to the Gulfs of Bothnia and Finland the upper layers of water, from 30 to 70 metres (16 to 38 fathoms) in thickness, have almost the same salinity throughout. In these waters a vertical circulation is kept up by convection currents. Beneath these layers are ma.s.ses of salter water, through which a thermal wave of small amplitude is slowly propagated to the bottom by conduction. These strata are practically stagnant, deficient in oxygen and surcharged with carbonic acid. Their salter waters must have been originally derived from outside, and must therefore have pa.s.sed over the plateau between Falster and Mecklenburg, but their horizontal extension is checked by the ridges separating the deep hollows in the Baltic from each other. The inflow to the deep basins is intermittent, probably with a long period of flux and reflux.

The circulation in the channels connecting the Baltic proper with the North Sea is of a complex character. It is necessary in the first place to distinguish clearly between outflowing and inflowing waters; in practice this is easily done, as the outflowing water always contains less than 30 parts _pro mille_ of salt, and the inflowing water more than 32 _pro mille_. The Baltic receives much more water by rainfall, discharge of rivers, &c., than it loses by evaporation; hence a surplus must be got rid of by an outflowing current which may be named the ”Baltic Stream.” The following general laws may be laid down with regard to this:--

1. That the Baltic Stream must be a surface current, because it originates from a redundancy of fresh water.

2. That, on account of the earth's rotation, the main part of the Baltic Stream must keep close to the coast of the Scandinavian peninsula.

3. That it must be a periodic stream, because the discharge of the rivers into the Baltic varies with the season of the year. In spring and summer the water from the Baltic is sufficiently abundant to inundate the whole surface of the Kattegat and Skagerrak, but in winter the sources of the Baltic current are for the most part dried up by the freezing of the land water.

All the waters which enter the Skagerrak or Kattegat as undercurrents can be found at the surface of the North Sea (_q.v._). They may be divided according to their origin and salinity as follows:--

(a) _Ocean water_ of 35 _pro mille_ salinity or more.

(b) _North Sea water_, the predominant water in the North Sea area, of 34 to 35 _pro mille_ salinity.