556 



SCIENCE. 



[N. S. Vol. XV. No. 379. 



tific journals, but there lias until very recently 

 been no extended report upon it. Hellmann 

 and Meinardus, of the Prussian Meteorolog- 

 ical Institute in Berlin, have just issued an 

 elaborate monograph on this subject, with the 

 title 'Der Grosse Staubfall vom 9 bis 12 Marz, 

 1901, in Nordafrika, siid und Mitteleuropa 

 (Abhandl. K. Preuss. Met: Inst., II., 1). The 

 region over which the dust fell extended from 

 the desert of southern Algeria north to south- 

 ern Denmark, i. e., over a distance of more 

 than 25° of latitude. There were dust storms 

 in southern Algeria on March 8-10; and as 

 the dust was carried northward it fell in Italy 

 and Sicily on March 10 ; over the eastern Alps 

 on the night of March 10-11; in central Ger- 

 many on the forenoon of the 11th; in north- 

 western Germany on the afternoon and even- 

 ing of the 11th and in southern Denmark on 

 the night of the llth-12th. In Algeria and 

 Tunis the fall was of dust; in Italy there was 

 a fall of dust during a dry stormy sirocco, and 

 rain heavily charged with dust also fell. In 

 Austria-Hungary and farther north the 

 phenomenon was everywhere associated with 

 some form of precipitation (rain, snow, frozen 

 rain, etc.). The amount of dust which fell 

 to the ground decreased from south to north. 

 Microscopical examinations of the deposit 

 collected in various places make it plain that 

 the dust was of terrestrial origin — an seolian 

 deposit resulting from the disintegration of 

 rocks in a desert region. The particles became 

 finer and finer with increasing distance from 

 their source in southern Algeria, and there 

 was noted a decrease in the percentage of 

 quartz from south to north. The northward 

 progression of the dust-fall was associated 

 with the advance of a barometric depression 

 from Tunis in a north-northeast direction to 

 the southern shore of the Baltic Sea, as shown 

 on the daily weather maps, and the pressures 

 at an altitude of 2,500 m. above sea level like- 

 wise indicate the presence of a southerly cur- 

 rent from Tunis to central Germany. The 

 velocity of this upper current was found to 

 be 70 km. an hour, and the dust-fall itself also 

 prog-ressed northward at the same rate. 



The report of Hellmann and Meinardus is 

 illustrated by means of several charts show- 



ing the pressures at sea level and at 2,500 m.; 

 the distribution of the dust over Europe; the 

 distribution of precipitation on March 12, at 

 7 A.M., and the distribution of temperature on 

 March 11 and 12. 'Der Grosse Staubfall' 

 will prove of special interest to geologists and 

 to geographers, as well as to the meteorolo- 

 gists for whom it was primarily written. 



JIETEOROLOGICAL CHART OF THE GREAT LAKES. 



The 'Meteorological Chart of the Great 

 Lakes, Summary for the Season of 1901,' by 

 A. J. Henry and N. B. Conger (U. S. Weather 

 Bureau), presents a number of interesting 

 facts concerning the meteorology of these im- 

 portant bodies of water. The navigation sea- 

 son of 1901 brought a record of 37 total losses 

 of vessels from weather conditions, and 11 

 from other causes. In addition, 140 vessels 

 were more or less damaged by weather condi- 

 tions, and of these, 34 cases were due 

 directly to fog. The total number of lives lost 

 through stormy weather was 90. Monthly 

 and annual normal fog charts are published 

 with the present bulletin, embodying the re- 

 sults of four years of fog observations. More 

 fog is encountered on Lake Superior than 

 elsewhere, and the conditions of fog forma- 

 tion are better understood there. On Lake 

 Michigan some of the fogs form in the sum- 

 mer a short distance out from shore during 

 early morning, and dissolve under the increas- 

 ing warmth of the sun's rays. The early 

 morning land and lake breezes often cause 

 banks of fog to form, sometimes as low-lying 

 fog, and at other times as dense banks, 

 with frequent openings of clear weather. In 

 autiunn, when cyclones move in from the 

 southwest, a blanlcet of fog appears, and may 

 last one, two or three days, with only an occa- 

 sional clearing. 



the seismograph as a sensitive BAROMETER. 



In a recent nuraber of the Quarterly Jour- 

 nal of the Eoyal Meteorological Society (Vol. 

 XXVIL, 1901, 293-298) there is a paper on 

 'The Seismograph as a Sensitive Barometer,' 

 by Mr. F. Napier Denison, of Victoria, 'B. C. 



A Milne seismograph was installed in 1898 

 at the Meteorological Office, Victoria, and the 



