16 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 
The Cycle Theory of Disturbances. 
About the year 1825 Heinrich Samuel Schwabe, an amteur 
astronomer of Dessau, Germany, began to observe and record 
sun-spots. He pursued his investigation for twenty-five years, 
and, in 1851, published the results of his labors. From the mass 
of data thus presented, a periodicity in sun-spot phenomena 
was first established. The subsequent investigations of Prof. R. 
Wolf of Zurich, and others confirmed the observations of 
Schwabe, fixing the period from maximum to maximum at 
approximately 11 1-9 years. 
The cause of sun-spot phenomena has been studied with great 
eare by De La Rue, Stewart and other investigators, who have 
promulgated theories assigning them to the influence of various 
planets in the solar system, or to the joint influence of several 
planets when in conjunction; but the theories thus proposed 
have not been accepted by the scientific world, because they 
were not considered as conclusively proven. 
In 1850 Lamont, of Munich, called attention to the fact that 
there is a regular perodicity in the maxima of magnetic distur- 
bances, as indicated by the variations of the needle, and fixed 
this period at 10 1-3 years. Subsequent investigations confirm- 
ed this theory. 
Prof. C. A. Young; [°‘The Sun’’ p. 163] says: °“*‘As soon as 
Schwabe announced his discovery of the periodicity of the so- 
lar spots, Babine in England, Gautier in France, and Wolf in 
Switzerland, at once and independently perceived the coinci- 
dence between the spot-maxima and those of the magnetic oscil- 
lation. * * * The convincing evidence as to the reality of 
the asserted connection lies in the closeness with which, ever 
since we have been in possession of continuous and satisfactory 
observations, the magnetic curve copies that of the sun-spots. 
* * * From 1820 to 1895 the record is almost continuous, 
and the coincidence of the curves is such as to make it impossi- 
ble to doubt the connection.”’ 
‘“When Loomis and other investigators came to collate obser- 
vations of aurore with those of sun-spots, they found an almost 
perfect parallelism between the curves of aurore and sun-spot 
frequeney.”’ 
The concurrence of maxima and general convariance of these 
three classes of phenomena—sun-spots, magnetic disturbances 
and aurore—have thus been established to the satisfaction of 
the seientific world. Thus the disturbances in the gaseous en- 
velope of the sun and the electric and magnetic phenomena per- 
taining to the earth are allied, either in the relation of cause 
