THE SOEAR SURFACE DURING THE PAST THIRTEEN 
YEARS— A REVIEW OF SUN-SPOT OBSERVA- 
TIONS MADE AT ALTA, IOWA, FROM 
1908 TO 1920. 
DAVID E. HADDEN 
My last paper contributed to the Academy of Science on solar 
observations covered the period 1903 to 1907 and was published 
in the Proceedings for 1908, Volume XV. The present paper 
brings the observations down to the close of 1920 and completes a 
series embracing thirty years of sun-spot observations. They do not 
pretend to be as complete during the last decade of this long per- 
iod as for the first twenty years for the reason that I was appoint- 
ed a member of the State Pharmacy Board in 1909, serving eleven 
years, and the duties of the office called me away from home very 
frequently, consequently the number of days on which the sun 
could be observed was materially diminished each year. The ob- 
servations represent the result of painstaking work during the in- 
tervals snatched from a busy business life and are presented to 
indicate what may be done by anyone, even if handicapped by nu- 
merous other duties, in this fascinating branch of astronomy. 
The instruments used in the thirteen years’ record were a 
inch refracting and occasionally a 9^ inch reflecting telescope, 
using Herschelian and polarizing eye pieces, grating spectroscope, 
position micrometer and various other necessary accessories. 
1908 
Decreasing activity which set in during the closing weeks of 
1907 continued during the first three months of this year, but a 
revival took place in April and some fine spots were seen. The 
greatest activity of the year occurred in August and September, 
the giant spots being easily seen with the naked eye. Diminishing 
activity and some spotless days marked the closing months. 
1909 
There was only a slight reduction, in the average monthly num- 
bers of groups, spots and faculae this year as compared with those 
of 1908. Large spots were present on the disc nearly every month, 
the exception being June, August, November and December. By 
