432 



SCIENCE 



[N. S. Vol. LIII. No. 1375 



course of produotion during the last decade is 

 shown in the following table. The unit of 

 measurement, it will be noted, is the metric 

 ton, which will be most easily remembered by 

 American readers as roughly equivalent to the 

 gross ton of 2,240 pounds. The fluctuations 

 in world coal supply, if expressed as index 

 numbers, taking the output in the year 1913 as 

 equal to 100, become as follows: 



97 



100 



99 



86 



»7 



1910 86 1916 



1911 89 1917 



1912 93 1918 



1913 100 1919 



1914 90 1920 



1915 89 



These figures are necessarily in part esti- 

 mated, for official statistics are slow in com- 

 ing in and for certain countries of eastern 

 Europe — ^notably Russia — even unofficial data 

 are lacking. The figures are presented as 

 tentative and subject to revision. As official 

 rejwrts are available for 92 per cent, of the 

 world's output, the margin of error in the 

 total probably does not exceed 1 or 2 per cent. 

 In comparing the 1920 output with that of 

 ithe years before the war it must be remem- 

 bered that the world's consumption of coal 

 norm,ally increases by leaps and bounds. The 

 average rate of increase in the 20-year period 

 preceding August, 1914, was 38,000,000 tons. 

 Of course the waste and disorganization of the 

 war have reduced the consuming capacity of 

 many countries, but in other countries, notably 

 the Fniited States, requirements have been in- 

 creasing at a rate greater if anything than be- 

 fore the war. 



The present rate of production in the world 

 is the resultant of conflicting forces; the de- 

 cline in the war-d;orn countries is being offset 

 in part by an increase in regions remote from 

 the battlefields. In the belligerent countries 

 of Europe the war cut heavily into production. 

 .Sometimes the cause of the decline was phys- 

 ical destruction of the m.ine3, as in France; 

 sometimes it was the drain upon the man- 

 power of the nation ; sometimes it was merely 

 the economic disorganization and disruption 

 of normal trade which attended the war. In 



France the 1920 output (excluding the Saar 

 and Alsace-Lorraine) was 46 per cent, less than 

 that of 1913 ; in Great Britain the decline was 

 20 -pev cent.; in Germany (also excluding the 

 Saar and Alsace-Lorraine) the output of 

 bituminous coal decreased 24 per cent., a de- 

 crease which was in part, however, offset by 

 the increased production of lignite. In east- 

 ern Europe the old Austro-Hungarian empire, 

 Eussia and the Balkans, the breakdown caused 

 by the war was even greater than in western 

 Europe, and the decline in output propor- 

 tionately large. Of all the major European 

 belligerents only Belgium had in 1920 prac- 

 tically reattained the pre-war rate of produc- 

 tion. 



While in 1913 Europe led all the continents 

 as a producer of coal, contributing 54 per 

 cent, of the world's output, in ' 1920 she had 

 yielded first place to North America and her 

 share of the world's total had shrunk to 46 

 per cent. The largest factor in filling the void 

 caused by the war in Europe was, of course, 

 the United States. Our production increased 

 from 38.5 per cent, of the total for the world, 

 )n 1913, to 45.1 per cent, in 1920. In that 

 year our seaborne exports of coal were 22,500 

 net tons, five times what they were in 1913. 



TOP MINNOWS AS YELLOW FEVER 

 ERADICATORS 



According to The Fisheries Service Bulle- 

 tin the success which has attended the use 

 of the top minnow {Gambusia) in eradicating 

 malarial mosquitoes in various parts of the 

 United States has led to the employment of 

 the same fish in combating an incipient epi- 

 demic of yellow fever at Tampico, Mexico. 



Dr. A. E. Stubbs, of the Standard Oil Co., 

 who visited the Washington office in March, 

 reported tliat cases of yellow fever appeared 

 at Tampico during the past summer, and 

 there was eveiy indication of a serioiis epi- 

 demic, as the conditions for the spread of the 

 disease among the natives were most favor- 

 able. In addition to numerous outlying 

 ponds, pools, sloughs, and marshes in which 

 mosquitoes breed, all of the native houses 

 have open barrels or other receptacles con- 



