246 



PROGRESS OF METEOROLOGY IN 1889. 



VIII.— BAROMETRIC PRESSURE AND ITS VARIATIONS; HYPSOMETRY. 



Die Vertheilung des Luftdrucl;cs ilher Mittel- und Sud-Europa darge- 

 stellt mif Grundlage der SOjdhrigen Monats- und Jahres- Mittel^ 1851-1880; 

 nehst allgemeinen Untersuchungen ilbcr die Ver Under liclilieit der LuftdrucTc- 

 Mittd und Diferenzen, sowie deren mehrjdhrige Periode, von J. Hauu, 

 Wien^ 1887. Tbis volumo ia "Band ii, Heft 2," of tbe Oeographische 

 Ahliandlungen, published by Prof. Dr. A. Penck. It is divided into 

 the following sections: Introduction. Chapter i. On the methods for 

 obtaining comparable mean air pressures and for drawing correct iso- 

 bars. II. Monthly and annual isobars of central and southern Europe. 

 III. Annual period in the air i)ressure relations of Europe, iv. Con- 

 nection between the air pressure anomalies of Europe and the tem- 

 perature anomalies in central Europe. V. The mean and absolute 

 variability of the monthly and annual means of air pressure, vi. The 

 probable error of the thirty-year mean air pressure, vii. The variabil- 

 ity of the differences of the mean air pressure of two places, viii. Re- 

 duction to the normal period of 1851-1880. ix. Reduction of the mean 

 air pressures to the same level, x. Many year period of the air pressure. 



The three plates at the end of the volume contain the isobars for each 

 month and the year reduced to sea-level, and for January, May, July, 

 October, and the year reduced to 500 meters elevation. The annual 

 period of air jiressure in various j)ortions of Europe is presented by dia- 

 grams. The curves are quite irregular, showing the phases from conti- 

 nental to oceanic climates. The relation between the temperature and 

 air pressure deviations for the seasons is investigated by Professor 

 Hann. One conclusion reached is that "in all cases of very warm 

 winter in central Europe the air iiressure in the northwest over the 

 Atlantic Ocean was too low; if neutral Europe alone be considered, 

 very cold winters occur just as frequently' by high as by low pressure." 

 The following table shows approximately the dependence on the lati- 

 tude of the average variability of the monthly and annual air pressures : 



1 



Latitude. 



Mean inoutbly , 

 Annual 



20C 



mm. 

 0.40 



(F. Waldo, Am. Meteor. Journal, v, p. 511.) 

 Effect of lunar attraction 07i the atmosphere. — Professor Bornstein, of 

 Berlin, has taken up the question of the effect of the moon's attraction 

 on the atmosphere. At Singapore, Melbourne, St. Helena, and Batavia 

 observers have succeeded in establishing a daily variation in the baro- 

 metric pressure dependent upon the moon, and having two maxima and 



