EDITORIAL 1 1 3 



being the twenty-fifth anniversary, was celebrated by a very 

 attractive programme. Papers were read by Winchell, Grant, 

 Sardeson, Berkey, and others upon various geological problems. 

 The Iowa programme included papers by Todd, Calvin, Keyes, 

 Udden, Sardeson, Bain, Leverett, and others and was particularly 

 interesting to students of the drift. The Wisconsin programme 

 embraced papers by Van Hise, Collie, Hobbs, Lurton, Slichter, 

 with a report of progress of the Geological and Natural History 

 Survey by Birge and Marsh. The Indiana programme was also 

 a strong one, and the Nebraska meeting, held some time earlier, 

 was well attended. The publication of the "proceedings of these 

 meetings will be awaited with interest. H. F. B. 



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Messrs. Spring and Rowland have recently communicated 

 to the Belgium Academy a series of observations made upon the 

 amount of carbonic acid contained in the atmosphere during the 

 year. They give the result of 266 determinations made in the 

 city of Liege, Belgium, on one side of which there is an indus- 

 trial and on the other an agricultural district. The average 

 amount of carbonic acid contained in ten thousand parts of air 

 was 5.1258 parts by weight and 3.3526 parts by volume. These 

 gentlemen remark that this is more than the amount contained 

 in the air of Paris, which is 4.831 parts by weight and 3.168 by 

 volume. The large amount at Liege is owing not only to the 

 large iron works there but also to the fact that the city is sur- 

 rounded by coal mines. To this the authors attribute the greater 

 heat of the city as it is well known that a small amount of 

 carbonic acid in the air causes the absorption and prevents the 

 radiation of heat. They also attribute the cold weather of May 

 to the diminution of the carbonic acid caused by its consump- 

 tion by the exceptionally vigorous growth of leaves at that 

 season. Their observations show that a fall of snow will 

 increase the amount to 3.761 by volume and that in cloudy 

 weather the amount was 3.571 parts and that there was always 

 a larger amount in winter than in summer. They also found 

 that the amount was diminished by high winds but increased 



