596 



SCIENCE 



[Vol. LV, No. 1431 



your remembrance the lielp you promised me last 



year. Sincerely yours, 



(Signed) K. Linsbauer. 



L. B. Becking 

 Department of Botany, 



Stanford University, California 



REQUEST FOR PAPERS ON GEOLOGIC 

 DIFFUSION 



I HAVE received from Professor Raphael Ed. 

 Liesegang, of the Institut fiir physikalische 

 Grundlagen der Medizin, Sehloss Str. 21, 

 Frankfurt am Main, who is well known for his 

 studies of diffusion and of the phenomena gen- 

 erally referred to as "Liesegang rings," a letter 

 in which he requests that geologists who may 

 publish, or who have recently published, papers 

 dealing with the relation of ore deposition to 

 colloid chemistry or diffusion will forward to 

 him copies of their works. He explains that 

 he desires these for abstracting for the "Kolloid 

 Zeitsohrift" and for use in the preparation of 

 new editions of his books on Geologic Diffusion 

 and on Agates. Hitherto he has obtained such 

 papers by personal letters to their authors, but 

 the present postage rate from Germany is so 

 high as to make a continuance of this practice 

 a heavy burden on his resources. 



Geo. Otis Smith, 



United States Director 



Geological Survey 



ATMOSPHERIC POLLUTION 



Readers of Sciexce have been in touch with 

 the work of the Committee for the Investigation 

 of Atmospheric Pollution. In the issue for 

 April 22, 1921, a review of the Sixth Report 

 is given, and in the issue for November 28, 

 1919, a summary of the Fourth Report. 



The Seventh Report has now appeared"^ 

 giving results of measurements of the deposits 

 from 31 stations. During the year, automatic 

 apparatus for measuring suspended impurity 

 was set up at sis stations. 



The tables are similar to those in previous 

 reports, and cover : 



1. Monthly deposit for two selected stations, 

 representative of high and low deposits such as 

 central Birmingham and Eothamsted. 



1 M. O. 249. Meteorological Office, Air ilinis- 

 try, London, 1922. Price 2s. 



2. Total solids deposited monthly at all stations. 



3. Mean monthly deposits at all stations for 

 the summer half years, i. e., April to September, 



1919 and 1920. 



4. Mean monthly deposits at all stations for the 

 winter half years, i. e., October to March, 1919- 



1920 and 1920-1921. 



5 and 6. Classification of the stations according 

 to amounts of various elements of pollution. 



7 to 10. Totals of stations as classified for each 

 element of pollution. 



There is also a discussion of the type of 

 deposit gage. The metallic gage, even when 

 varnished, gave traces of metallic salts; and 

 the glass gage proved too fragUe; and finally 

 enameled stoneware was adopted. One set of 

 gages has been provided with Nipher shields 

 to improve the catch ; and it would seem as if 

 the amount so caught now agreed closely with 

 the catch of the rain gage, which was not the 

 case previously. 



A twin atmospheric pollution gage has been 

 devised and put in operation at Rochdale by 

 Dr. Ashworth and an attempt made to measure 

 the quantity of impurities brought into the 

 town and the amount carried out. 



The west wind brought 14.8 tons per square 

 kilometer; and 11.84 tons were carried out by 

 the east wind. The data covered a period of 

 five months. The amount brought in by the 

 west wind, however, is not sufficient to account 

 for Rochdale's high atmospheric pollution. 



From the records of the instruments at the 

 Meteorological Office it would appear that in 

 London domestic fires are responsible for 

 nearly two thirds of the total smoke. 



The relation between health and impurity is 

 discussed by Dr. J. S. Owens. 



Curves were prepared in which the daily 

 deaths of London were plotted with the data 

 for maximum suspended impurity in the air. 

 Temperatures were also considered. 



There is a tendency for the death rate to 

 reach a maximum when the impurity is highest 

 or rather a little later. 



On the whole there is no obvious relationship 

 between the quantity of impurity and the num- 

 ber of deaths in London. 



Dr. Owens also contributes an article on 

 "London Fog in November," describing meas- 

 urements made of the black particles. These 



