MAGNETIC SURVEY OF JAPAN. 227 



In discussing the Declinations we come face to face with the 

 objection already touched upon (see Section I), namely, the lack in 

 the earlier survey of any atteui])tat obtaining a really good mean daily 

 value at every station. If we take the vahies as they are given in 

 ]\Ir. Sckino's lists, we shall iind, on the whole, absoUitcly no indica- 

 tion of a secular variation. The mean difference is — U'.07, an 

 altogether insignificant cjuantity. If, liowever, we apply ])ro1jable 

 corrections to the observations, so as to reduce them to the daily mean, 

 the mean difference will be + 0.8, — that is, an increase of 0'.2 ])er 

 year. As regards the declination, then, we may conclude that, within 

 the period beginning 1883 and ending 1887, there is practically no 

 change, or if there is, it is a very small change indeed. It looks 

 almost as if we were just passing through a time of maximum 

 declination. 



Finally, it may be remarked that a comparison of our results 

 with those of other experimenters leads to the conclusion that within 

 the present decade there are but small evidences of secular change in 

 the magnetic elements. There is a suggestion that the Dip is dimi- 

 nishing and the Horizontal Force increasing ; but the Declination 

 seems to have reached a stationary point. 



