2738 



DUSUN 



Diisseldorf. 



The town seen from the left bank of the Rhine, where it is 

 spanned by the bridge built in 1896-98 



extended 1804-13, whose Castle 

 Court was immortalised by Heine, 

 is one of several delightful pleasure 

 grounds; another is the Kaiser 

 Wilhelm Park. 



There are many educational in- 

 stitutions, industrial and historical 

 museums, a public library, a munici- 

 pal theatre, palace of justice, post 

 office, banks, hospitals, and a ceme- 

 tery. The Academy of Art, a 

 famous school of genre painters, 

 founded by the elector Charles 

 Theodore, 1767, is housed in a 

 Renaissance building, 1879, with 

 lecture hall. The greater part of 

 the collection of old masters in 

 the origina 1 picture gallery, founded 

 by the elector Johann Wilhelm, 

 was removed to Munich in 1805. 

 The Diisseldorf art school flourished 

 1820-40 under Peter Cornelius and 

 W. Schadow. The Kunsthalle or 

 municipal art gallery, 1881, en- 

 larged 1902, with frescoed stair- 

 case, is devoted to modern work. 

 Of recent years Diisseldorf has de- 

 veloped large iron, textile, brewing, 

 distilling, printing, dyeing, and 

 other industries, and has become 

 an important banking centre. Gas, 

 waterworks, tramways, and electric 

 plant belong to the municipality. 

 "* First mentioned in 1159, Diissel- 

 dorf received municipal rights in 

 1288. Early in the 16th century it 

 was the residence of the dukes of 

 Berg, and from 1609-1716 that of 

 the princes palatine. In 1795 it 

 became French and in 1815 was 

 annexed to Prussia. It was in the 

 neutral zone after the Great War. 

 In the town were born the painters 

 Cornelius and Schadow, the philo- 

 sopher Friedrich H. Jacobi, and 

 the poet Heine. Pop. 360,000. 



Dust. Fine dry particles of 

 matter. Dust is of great import- 

 ance, a fact which, however, has 

 only been fully recognized within 

 recent years. Without the presence 

 of dust in the atmosphere, for ex- 

 ample, there would be no cloud 

 formations. John Aitken showed 

 (1880) that the particles of dust 

 in the atmosphere act as centres of 



condensation for the formation of 

 rain drops. Without dust the 

 atmosphere would reach a higher 

 state of saturation than now holds, 

 resulting in the condensation of 

 watei*on buildings, trees, etc., and 

 on the clothing, as in mists. 



Atmospheric dust particles are 

 so small that the microscope has 

 failed to distinguish many of them, 

 and Aitken invented an instru- 

 ment, known as the dust counter, 

 for estimating the amount of dust 

 in a given volume of air. Large cities 

 show a heavy amount compared 

 with country districts, while the 

 air of mountain districts is freest 

 from dust, particularly the High- 

 lands of Scotland. But on Ben 

 Nevis over 14,000 particles of dust 

 per cubic centimetre have been 

 recorded, and over a quarter of a 

 million in big cities. 



Volcanic dust is composed of 

 minute mineral fragments ejected 

 during volcanic eruptions. Some- 

 times called ash, it comprises the 

 pulverised forms both of lava and 

 of sedimentary rock dislodged from 

 vent- walls. The distance from the 

 originating centre at which any 

 particle settles on land or sea is 

 determined by the relation of its 

 mass and maximum elevation to 

 the force and duration of the wind. 



Dust from the great Iceland 

 eruption of 1783 destroyed the 

 crops in Caithness, Scotland. After 

 the eruption of Soufriere, St. Vin- 

 cent, in 1812, 3,000,000 tons of 

 " May dust " fell 100 m. away on 

 Barbados. The Tomboro eruption 

 in Sumbawa, 1815, distributed 50 

 cubic m. of material 185 times 

 the mass of Vesuvius over 

 1,000,000 sq. m. The most impal- 

 pable particles may float in the 

 upper air for long periods, being 

 indeed a predominant source of 

 atmospheric dust everywhere. At 

 Krakatoa, Malay archipelago, Aug. 

 26-27,1883, the dust-column, rising 

 to 30 m., caused darkness for 150 

 m. around. Some of it completed 

 the circuit of the earth in 15 days, 

 and remained floating at high ele- 



vations for three years in a belt 

 between 60 N. and 10 S., pro- 

 ducing remarkable sunsets seen in 

 all parts of the world. 



Vast areas in Nebraska and Kan- 

 sas, U.S.A., are covered with an- 

 cient volcanic dust up to 30 ft. 

 thick. When such deposits, formed 

 in geological time, are subsequent!}* 

 consolidated, they are called tuffs. 

 Submarine eruptions are attended 

 by similar phenomena, producing 

 volcanic muds. 



The inhaling of dust is respon- 

 sible for chronic disease of the lungs 

 and air passages, increasing suscep- 

 tibility to tuberculosis. Those 

 most frequently affected are miners, 

 quarrymen, earthenware and pot- 

 tery manufacturers, cutlers, file 

 makers, etc. The evil is reduced to 

 a minimum by efficient ventilation, 

 the use of hoods which prevent the 

 dust from rising to the worker, 

 or outlet shafts which draw it away 

 as formed. In some processes it is 

 possible to keep the dust down by 

 sprinkling with water. 



Dust-Storin. Wind-current of 

 great velocity, laden with minute 

 solid particles. The distance to 

 which dust derived from the desic- 

 cated surface of exposed soil is 

 transported is determined by the 

 force and duration of the wind 

 The local air-eddies which raise 

 " March dust " are dust-storms in 

 miniature. They especially char- 

 acterise the dry desert-winds of 

 wide, arid regions. The result of 

 dust-laden wind-drift long con- 

 tinued is seen in such deposits as 

 the clayey loess, sometimes 2,000 

 ft. thick, of N. China. 



In central Asia the noonday sun 

 is often obscured by fine, yellow 

 loess-dust. On April 2, 1892, a 

 dust-cloud, mostly of loess felspar, 

 covered 2,000 m., and was driven 

 400 m. out into the China Sea. The 

 Sahara is another potent breeding 

 ground of dust-storms, called in 

 Egypt the khamsin, hi the Mediter- 

 ranean the sirocco, in Madeira 

 the leste, in Guinea the harmattan, 

 in W. Asia the simoom. It causes 

 dry, red fogs off the W. African 

 coast ; when rain falls through 

 them, so-called blood-rain results. 

 A storm of March 9-12, 1901, trans- 

 ported 1,800,000 tons of fine 

 Saharan dust across Europe to- 

 wards Russia. 



Dusun. Primitive people of 

 Indonesian stock living in N. 

 Borneo. Estimated (1911) at 

 88,000, they form an important 

 part of the Murut group. They 

 have absorbed an immigrant 

 Chinese strain, and adopted buffalo 

 drawn ploughs and systematic irri- 

 gation. Tall, slender, long-headed, 

 they are darker than the land Dyak 

 of the Klemantan group. 



