B. TERRESTRIAL PHYSICS AND METEOROLOGY. 33 



them on a map, so as to show, clay by clay, the general char- 

 acter of the weather throughout the United States. For sev- 

 eral years prior to the beginning of the war this system was 

 carried on regularly, and was of great interest to visitors to 

 the Institution. The occupation of the telegraph lines for 

 military purposes, and the fire in the Smithsonian building, 

 broke up the arrangement ; and it was about to be resumed 

 when the government undertook the work, thereby relieving 

 the Institution from the necessity of its further prosecution. 



RELATION OF THE BAROMETER TO THE WEATHER. 



M. De Fonvielle, an eminent meteorologist, endeavors to 

 show the reason why an increased atmospheric pressure gen- 

 erally accompanies fair weather, and a diminished pressure 

 wet. According to his theory, the dry winds come from the 

 north or northwest, and hence, traveling from a cold region, 

 the air has a tendency to descend, and, therefore, to increase 

 the pressure of the atmcTsphere, as shown by the rising of the 

 barometer. On the other hand, the winds laden with moist- 

 ure usually come from the south or southwest, consequently 

 causing a diminished pressure, and a fall of the barometer. 

 13 A, February 1,1871,121. 



METEOROLOGY OF THE NORTH ATLANTIC. 



A report has just been published in Bremen of the meteor- 

 ological and physical conditions attendant upon the voyages 

 of the North German steamers between New York and Bre- 

 men during 374 passages. From this it appears that float- 

 ing ice is met with principally between the meridians of 46 

 and 51, and is more abundant east of that region than west 

 of it. The general direction in which the storms blow is said 

 to be between west and north-northwest; also, that fifty per 

 cent, of the entire number occurred during November, De- 

 cember, and January; twenty-six per cent, during February, 

 April, and October ; twelve per cent, during March and Sep- 

 tember; and the remainder distributed over the remaining 

 four months, from May to August. They reach a maximum 

 at 30 west longitude, and maintain it to 45 west, their di- 

 rection being northwesterly. From these facts, Von Freeden, 

 the author of the article, concludes that the storms begin in 

 the neighborhood of the Banks of Newfoundland, where the 



B 2 



