RECENT VALUES OF THE MAGNETIC ELEMENTS. 437 



graphical position had to be extracted from a map, and in 

 others where conflicting statements existed, there may not 

 unlikely be appreciable error. 



The data in the table are deduced from hourly readings 

 of the magnetic curves in the case of Pawlowsk, Copenhagen 

 (April — December only), Kew, Greenwich, Falmouth 

 (declination and horizontal force), Pare Saint Maur, Pola, 

 Perpignan, Tiflis, Washington, Zi-ka-wei, Manila, Batavia 

 and Mauritius (?). In the case of Hamburg (declination), 

 Wilhelmshaven, Vienna (declination and horizontal force), 

 Prague, Coimbra (declination), Lisbon (declination), Hong 

 Kong and Colaba (all elements but declination) the diurnal 

 inequality has been at least partly, in some cases probably 

 with great exactness, allowed for by taking readings from 

 curves or absolute instruments at two or more different 

 hours. In other cases the hour selected for observing a 

 particular element may more or less accord with the time at 

 which it has its mean daily value, but information on this 

 point is lacking. In a few cases, e.g., Rome, where regular 

 magnetic work seems only commencing, the recorded ob- 

 servations are perhaps somewhat few to supply a satisfac- 

 tory annual mean. 



Charles Chree. 



30 



