154 E. Loomis on Solar Spots, Magnetic Declination, ete. 
a yearis the relative number for er year. Dr. Wolf has con- 
tinued these observations to the present time, and the h 
clearly a minimum in 1856 and a in 1867, the interval 
being 11 years. 
Dr. Wolf has made a most thorough examination of the 
records of Astronomical observers, since the invention of the 
telescope in 1608, and has aimed to deduce a similar series of 
numbers which shall be proportional to the amount of spotted 
surface of the sun for a period of 260 years. In this attempt 
_ he has been remarkably successful, and he claims to have de- 
termined the date of every maximum and every minimum of 
the solar spots since 1608. He — also published a table of 
relative numbers for each year since 1700, in which, however, 
find 86 years marked with an interrogation point, indicating 
that the numbers for those years are specially unreliable, of 
were derived by interpolation. Since 1749 only 12 years 
thus marked with an interrogation point. These years are 1774, 
1792, 1798, eee to 1807, and 1814-5. From 1749 to 1826, 
schaft, in Zuri 
Obs. from 1700-1748 ve Kireh, vol. 12,!Obs. from 5 sg po Flaugergues, 
42. 
6, p. 4 
17 et by Plantade, vol. 5, sg 1800-1818 ie? ‘Heinrich, vol. 
- 1tie-11 26 by Rost and Alis- aahicre by Stark, vol. 3, 
0. i 
ez, vol. 5, p. 261. 
1742-1751 by Hagen, vol. 4, 
p. 250. 
le igs by Staudacher, vol. 
p.2 
pong: by Zucconi, vol. 2, 
1769 a “Horrebow, vol. 10, p. 
13-1777 by Mallet, vol. 3, p. 
1816-1825 by Tevel, vol. 4, p- 
1819-1823 by Adams, vol. 6, 
1826-1868 by Schwabe, vol. 1, 
p. 266; vol. 5, p. 1, 
1849-1868 by Wolf, de 1, to 
14, 
1854-1860 by Carrington, vol. 
9, p. 2 
have no reason to doubt that the ively nentine which 
I 
Dr. Wolf has derived from thes 
ese observations are generally as 
Ain as can be popes from the materials employed, but I 
mbers need some correction for the years 1793 an 
1794 and and “probably ast for 1795. His numbers from 1787 
tol 
1787 92:8* 1790: 168 1798 «=. 20°77? 
1788. 90°6* 1791 46-1 1794 9-289 
2 89 («8H 4 1792 52:7? 1795 165 
ropose to examine into the accuracy of these nambers for 
roe and 1794. 
a 
j 
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