528 EXPEKIMENT STATION RECOED. 



Meteorology (An. EaUuh Mcricana. 12 (lOO'f). Xo. 12, pp. 27-.',2) .—Thin 

 i-eport gives summaries of meteorological conditions as observed at the City of 

 Mexico during 1004, and at a number of other places in the Republic of Mexico, 

 with a discussion of seasonal variations in weather conditions. 



Hourly meteorological and magnetic observations, Manila central ob- 

 servatory, 1904 (Ann. Rpt. Philippine Weather Bur., ISOJf, pts. 1 and 2, pp. 

 20S, eltarts 2). — This report records in part 1 the results during 1904 of hourly 

 observations at the central observatory at Manila on atmospheric pressure, tem- 

 perature, relative humidity, vapor tension, direction and force of the wind, and 

 direction, form, and amount of clouds, and bi-daily observations on ozone ; and 

 in part 2, observations during the same period at the magnetical observatory on 

 declination, horizontal force, inclination, and other disturbances, as measured 

 by Mascart registering instruments. 



Precipitation in North German river basins, G. Hellmann (Die A"/e- 

 (Ier.schl(i(/e in den Norddeiitschen Strom f/ehieten. Berlin: Dietrich Keimer, 

 1906, vols. 1. pp. V + 386 -f 139, pis. 3, figs. //S, map. 1; 2, pp. VII + 722; 3, pp. 

 VII + 812). — A review of this work in Briti.s-h Rainfall 1905. refers to it as 

 " the most remarkable compendium of rainfall data which has ever been pub- 

 lished." It is a compilation, under the direction of the chief of the Royal Prus- 

 sian Meteorological Institute of Berlin, of all available rainfall data up to the 

 year 1900, the earliest records included dating back to 1715. 



Observations at 4,000 stations are included. The data are discussed with 

 reference to amount, frequency, and variation of rainfall. 



A study of the longest records reduced to their average value for the 50 years 

 1851-1900 shows that the lowest mean annual rainfall in the region under 

 consideration is about IS in., the greatest about 58 in. 



The average seasonal changes for the whole region are comparatively regular, 

 February having as a rule the least rainfall and July the greatest, with a regu- 

 lar decrease following that month. Under the maritime conditions of the 

 western part of the area, however, there is a tendency for the maximum to 

 occur later in the year, in the extreme south and southeast to occur earlier. 

 Over southern and central Germany the driest month is January, in the north- 

 east February, and in the extreme north and northwest April. The rainfall of 

 winter is 24 per cent of the annual total in the extreme west, diminishing 

 steadily toward the east and south until it becomes less than If! per cent at the 

 sources of the eastern rivers. In the spring the rainfall increases from about 

 18 per cent of the total in the northwest and 20 per cent along the Baltic coast 

 to more than 24 per cent in the valley of the Danube. The sununer rainfall is 

 30 per cent of the total annual rainfall on the North Sea coast and 40 per cent 

 in the heart of the continent. In autumn 30 per ceirt of the total rainfall occurs 

 along the North Sea and Baltic coasts and 22 per cent in the central and soutlk- 

 ern states. 



Leaving the mountainous regions out of account, the number of rainy days 

 decreases from iibout 175 in the northwest of Germany to 135 or less in the 

 southeast, the variations in different parts of Germany being somewhat irregu- 

 lar. In the north and west the months which have most frequent rains are 

 October, November, or December, and the month having the least frequent rains 

 April. In central Germany most frequent rains occur in July and least fre- 

 quent usually in September. In the south June has most rainy days and No- 

 vember or January least. 



In a study of variations in rainfall it was found that there was a greater 

 tendency for a run of consecutive dry months than for a run of consecutive 

 wet months. A relation was traced between variations in annual rainfall and 

 suuspot frequency, each sunspot period including 2 rainfall maxima, closely 



