B. TERRESTRIAL PHYSICS AND METEOROLOGY. 117 



the maximum temperatures in the fall and winter are some- 

 what lower in the city, while in the spring and summer they 

 are somewhat higher. On clear nights the difference be- 

 tween the minimum temperatures in the city and the coun- 

 try may amount to 13^ Fahr., that in the country being the 

 lower of the two. Also, the annual average difference be- 

 tween the maxima and the minima is greater for the country 

 than the city. Yurteljahres -tfevue, II., i., 139. 



SELF-RECORDING BAROMETERS. 



A memoir, by Wild, of St. Petersburg, on the means of 

 keeping continuous records of barometric observations, has 

 recently appeared, in which he shows that the electric self- 

 recording barometer devised by him, and called the balance 

 barometer, is compensated for temperature, and gives results 

 whose accuracy is equal to that of the best direct observa- 

 tions with ordinary quicksilver barometers. Of all methods 

 of recording the barometric pressure, Wild gives the prefer- 

 ence to the electric, as compared with the photographic. 

 Der JSTaturforscher, p. 186. 



TEMPERATURE AND PRESSURE DURING THE MONSOON MONTHS. 



In an article on the climate of Asia in the region of the 

 monsoons, Hann states : 



1. That the annual mean diminution of temperature with 

 altitude is, in the tropics, in general, perhaps not greater than 

 in Central Europe. 



2. During the regular monsoon, the diminution of tempera- 

 ture with altitude is slow on the windward side of the mount- 

 ains, but rapid on the leeward side. 



3. It can not be proved that the condensation of the enor- 

 mous mass of aqueous vapor during the rainy season in the 

 East Indies increases the temperature of the air in the higher 

 stations, not even in those places where it might have been 

 expected. 



4. A phenomenon that is in intimate connection with the 

 constant winds of the regions of the monsoons consists in the 

 fact that a perceptible annual period exists, in the differ- 

 ences of atmospheric pressure, at stations of various altitudes. 

 These differences have their greatest value when the wind 

 blows from the lower to the higher stations, and their small- 



