C. A. Schott on Magnetic Declination, ete. 149 
Such great gifts of nature, combined as they are, with an un- 
surpassed variety of favorable circumstances, both climatal and 
Art. XVII.—The present annual effect of the secular change of 
the Magnetic Declination in the Eastern part of the United States, 
accompanied by a Chart; by CHarLES A. Scuort, Assistant 
U.S. Coast Survey. 
[Published in this Journal by permission of the Treasury Department, and commu- 
nica y Prof. A. D. Bacue, Superintendent U. S. Coast Survey.] 
IN a preceding number of this Journal (vol. xxix, May, 
1860), I have given a special discussion of the secular variation 
to which the magnetic declination in the eastern portion of the 
United States appears to be subject: in the present communica- 
tion will be found some additional material, since collected, with 
a chart of isomagnetic curves of the annual change of the decli- 
is sufficiently plain from the discussion above referred to, but 
they may be taken to answer for about a decade either way from 
date, without passing beyond the limit of uncertainty to which 
i °y are subject themselves. The year 1860 may en for 
their avera fe epoch. igs eg ote tai 
_ The curves marked thus: 1, IU, IV, V, indicate the localities | 
Where the annual increase of west declination amounted, on the 
average, to as many minutes, between the years 1850 and 1860. 
, the change at. Eastport, Me., +1/°6 appears singularly small, 
but monthly observations, continued between 1860 and 1864, : 
& verification of last summer, will not admit of any other 
