DISCOVERY 



A MONTHLY POPULAR 

 JOURNAL OF KNOWLEDGE 



Vol. Ill, No. 29. MAY 1922. 



PRICE Is. NET. 



DISCOVERY. A Monthly Popular Journal of Know- 

 ledge. 



Edited by Edward Liveing, B.A., Rothersthorpe. 

 Northampton, to whom all Editorial Communications 

 should be addressed. (Dr. A. S. Russell continues to 

 act as Scientific Adviser.) 



Published by John Murray, 50A Albemarle Street, 

 London, W.i, to whom all Business Communications 

 should be addressed. 



Advertisement Office : 34 Ludgate Chambers, 32 

 Ludgate Hill, London, E.C.4. 



Annual Subscription, 125. 6d. post free ; single numbers, 

 15. net ; postage, 2d. 



Binding cases for Vol. 11, 192 1, are now ready. Price 

 25. 6d. net each ; postage gd. 



liow great is the part played by " chimneys " in these 

 fogs. A problem, however, which has never hitherto 

 been satisfactorily cleared up, is their very sudden 

 development, particularly in London. How many 

 times has one not woken, especially during the " season 

 of mists and mellow fruitfulness," to a clear, blue sky, 

 only to find oneself three or four hours later plunged 

 into the gloom of a " pea-soup " fog ? To how great 

 an extent " the quantity of smoke emitted during this 

 time in London is sufficient to account for the quantity 

 of impurity found in the fog," i.e. for the density of the 

 fog, is discussed by Dr. J. S. Owens in a paper in the 

 latest report on Atmospheric Pollution ' issued by the 

 Meteorological Office, Air Ministry. 



Editorial Notes 



In this number Professor Alfred Wegener gives his first 

 account in English of his theory of the origin of the 

 continents and oceans. It has as yet received very little 

 attention in this country on account of the difficultv 

 of obtaining German publications during the war. 

 Professor Wegener first put forward his theory in 1915, 

 and repubUshed it in 1920 imder the title " Die 

 Entstehung der Kontinente und Ozeane " (" The Origin 

 of the Continents and Oceans "). We must leave the 

 article to speak for itself, but we here quote the opinions 

 of Professor Weiss, Professor of Botany at Manchester 

 University, writing in the Manchester Guardian on 

 March 16, that the new theory is one " of fundamental 

 importance to the sciences of geography and geology, 

 as well as of great interest to the biological sciences," 

 and that " for the moment . . . it . . . constitutes 

 a good working hypothesis, and the striking simplicity 

 with which it allows many phenomena to be explained 

 will greatly stimulate further inquiry." 



One of the most welcome signs of approaching 

 summer to Londoners and inhabitants of our large 

 manufacturing towns is the, less frequent visitation of 

 fogs. For several years past it has been recognised 



Dr. Owens made a microscopic examination of the 

 fog air on November 5, 1920. A small jet of air im- 

 pinged on the glass slide produced masses of particles 

 of about i/3,oooth of an inch in diameter, the in- 

 dividual particles in these masses varying in size from 

 i/ioo,oooth to i/2o,oooth of an inch. " It is note- 

 worthy," writes Dr. Owens, " how very small a 

 quantity of impurity is sufficient to cause a dense 

 fog, and this is doubtless due to the extremely small 

 dimensions of the individual particles." The investi- 

 gator calculates that, for the production of a really 

 dense fog over London, about 190 tons of suspended 

 matter are required. He estimates roughly that in 

 London factory fires discharge eight or nine tons of 

 smoke into the air every hour, and domestic fires 

 about thirty-five tons, which in " over four hours of 

 winter months would represent 176 tons." It should 

 be noted that the average for the early morning hours 

 in regard to factory smoke would be larger than that 

 calculated from the complete working hours, owing to 

 the fact that " fires are being made up and steam 

 raised for the day's work." " It is not, therefore, 

 remarkable," concludes Dr. Owens, " to find 190 tons 

 hanging over London at 10 a.m. on a foggy morning, 

 as the amount of smoke produced during the previous 

 four hours is sufficient to account for it all." 



1 See under Books Received. 



113 



