248 E. Loomis— Comparison of Auroral Displays 
These numbers have all been projected upon the lower portion 
of the accompanying chart, Plate II, and the curve line thus 
obtained is therefore to be regarded as indicating the fluctua- 
tions in the sun’s spotted surface since 1776, according to the 
results of Dr. Wolf: 
and partly from the Beobachtungen zu Prag. Some of these 
numbers differ from those given in my former article (this 
Jour., vol. 50, p. 161), those values for some of the years being 
simply the difference between the mean declination for the year 
at 8 A. M. and 2 P. M. 
Diurnal inequality of the magnetic declination at Prague. 
Year.| Dec’n. Authority. || Zear. Dec’n. Authority. 
1851) 832 | Vierteljahrsschrift, iv, p.225||1862| 8’-59 |Vierteljahrsschrift, ix, p.116 
1852, 8-09 “ “ 1863} 8°84 ¥ # 
1853! 7-09 “ “ 1864| 8-02 “ x, p. 155 
1854 6°81 Me uf 1865| 8-14 |Prag Beobach., 1870, p. 16 
1855) 6°41 te “ 1866| 7°65 + * 
1856| 5°98 “ “ 1867} 7°09 * as 
1857} 6°95 “ “ 1868} 8°15 "¢ = 
1858) 7:4] “ “ 1869) 9°44 a , 
1859) 10°37 “ vi, p. 418||1870| 11-41 “ -1871, p. 21 
1860) 10-05 “ “ 1871| 11°60 es 8 
1861) 9°17 “ vii, p. 230 
These numbers, combined with those given in my former arti- 
cle from 1777 to 1850 (this Jour., vol. 50, p. 161), are projected 
r of auroral exhibitions each year, I have 
depended almost exclusively upon the catalogues of auroras 
by Prof. Joseph Lovering. These catalogues consist of a gene- 
ral list of auroral displays from 500 B. C. to 1864, embracing 
about 10,000 cases; also a second list, embracing nearly two 
thousand additional cases; and a third supplementary list, con- 
taining several hundred cases not included in either of the 
preceding lists. Finally, there are four pages of addenda and 
