PHYSICS OF THE GLOBE. 57 



regularity as Forel finds for Lake Geneva, although possibly- 

 such may be revealed by self-recording instruments. 



The oscillograph is the name given by Bertin to an appa- 

 ratus for recording continuously the rolling and pitching of 

 a vessel at sea. The apparatus has been lately extensively 

 used in the French navy, and affords important data both 

 for ship-builders and for students of wave motion. It is also 

 applicable to the determination of that correction to an ane- 

 mometer record on shipboard needed in order to obtain the 

 correct velocity of the wind at sea. 



An important paper on the progression of waves was 

 read by Osborne Keynolds at the Plymouth meeting of the 

 B. A. A. S., and an equally important one by Lord Ray- 

 leigh on the same subject was presented to the Mathemat- 

 ical Society in November. 



THE ATMOSPHERE. 



INTRODUCTORY. 



The following brief notice of the scientific activity of the 

 year in the department of meteorology brings our record 

 down to the last of December; and, however imperfect it 

 may be, yet suffices to show that but few preceding years 

 have been marked by more important events. Among these 

 latter we would place the extension of the United States 

 network of meteorological observers over the elevated re- 

 gions west of the plains of the northwest and southwest, the 

 extension of its system of international simultaneous obser- 

 vations to the vessels of the United States Navy and the 

 United States, British, and German merchant marine ; the 

 publication of several volumes by the new India Meteoro- 

 logical Office under Blanford ; the works of Brault on the 

 winds of the Atlantic; those of Guldberg and Mohn on the 

 mechanical laws that pervade the cyclonic and anticyclonic 

 areas of wind and pressure; and the elegant memoir ofFerrel 

 on the general circulation of the atmosphere, with accom- 

 panying polar charts of isotherms and isobars. 



INSTITUTIONS AND PERSONS. 



The Army Signal Office, although somewhat hindered by 

 a diminution of its quota of men, has continued its labors 



C 2 



