434 



NATURE 



[December 17, 1914 



are sufficiently interesting and important to be re- 

 produced here. 



Table I. — Summary of Reports per Month ending 

 April 30, 1914. 



Metric tons of deposit per sq. kilometre 

 in month of April 



Insoluble matter 



Soluble matter 



Table II. — Summary of Reports for Month ending 

 May 31, 1914. 



Adding together the results recorded in Tables I. 

 and II., and arranging the towns in order of the 

 magnitude of their fall of soot and dust in the two 

 months, we obtain the figures given in Table III. 



NO. 2355, VOL. 94] 



Table III. — The Soot and Dust Fall of various 

 English and Scotch Towns in April and May. 



The difference between the figures in the second and 

 third colunms of this table gives the soluble solid 

 matter brought down by the rain. 



It is surprising to find that the atmosphere of 

 Birmingham and of many northern towns is con- 

 siderably dirtier than that of London, which in this 

 respect has a reputation it does not deserve. Malvern 

 is seen to be far the cleanest town in the list, since 

 the total soot and dust-fall in April and May, 1914, 

 only amounted to 4-45 tons per sq. km., or to about 

 one-fifth that of London, and one-eighth that of 

 Liverpool during the same two months. 



Figs. I and 2 are sectional elevations of the standard 

 gauge, while Fig. 3 shows the gauge used for the 

 observations of London's soot-fall, carried out in 

 1910-11 by the Lancet and the Coal Smoke Abatement 

 Societv. 



THE NATURAL HISTORY OF AN 

 AMERICAN DESERT BASIN."^ 



THE staff of the Botanical Research Department 

 of the Carnegie Institution of Washington has 

 made many valuable contributions to natural science, 

 particularly in the study of desert vegetation, at the 

 Desert Laboratory, Tucson, Arizona. The recently 

 issued monograph on the Salton Sea is in many respects 

 unique, for it deals with a remarkable series of 

 phenomena, opportunities for the study of which are 

 but rarely presented. That the Desert Laboratory 

 workers have taken full advantage of this opportunity 

 is evident from the perusal of this volume, interest- 

 ing to the geologist, the geographer, and, above all, 

 to students of plant ecology. The chief interest of this 

 fine piece of co-operative research centres, as the 

 editor and chief contributor point out, around the 

 fate of organisms overwhelmed by floods, in the 

 physical changes which follow emersion, and in the 

 biological mechanism of reoccupation of sterilised 

 areas as they emerge from the water — episodes which 

 must have been repeated many times in the history 

 of the earth's surface. The report gives the results 

 obtained by the investigation from various points of 

 view of the phenomena presented by a desert basin 



1 "The Salton Sea: a Studv of the Geography, the Geology, the 

 Floristics, and the Ecology of a Desert Basin. " By D. T. MacDougal and 

 Collaborators. Pp. x -1-182-1-32 plates. Publication No. 193. (Washington: 

 i Carnegie Institution, 1914.) 



