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solar activity he derives a period of 34.4 years. From the maxima 
of the magnetic curve this period is found to be 35.25; from the 
total spotted area 35.5. The total mean is 34.89. For further particulars 
Lockyerr’s article must be consulted. 
The result agrees fairly well with the most probable period 
derived by Bricxner') from several meteorological phenomena, viz. 
348 + 0.7 years. 
Now it would certainly be extremely important if BRÜCKNER’s 
period were confirmed by the results of an independent investigation. 
For, though this period — after having been long contested — has 
become rather popular of late and has been adopted by a great 
number of meteorologists, particularly in Germany, it still cannot in 
my opinion be considered as being firmly established. Investigations 
such as those of Prof. Dubois are certainly important for this reason, 
though of course there may be a difference of opinion about the 
question whether a 35-year period can really be made out in the 
series communicated by Prof. Dugors. 
The 35 year period found by Lockynr in the solar activity seemed 
very remarkable therefore. So, for instance, prof. Jurrus Hann writes 
in his excellent text-book’): “Durch die neuerdings aufgestellte 33 bis 
“35-jährige Sonnenfleckenperiode scheint nun auch eine Ursache für 
“die 35-jahrige BrückNersche Periode gefunden zu sein.” Similarly 
prof. Dusors*) writes: “Since W. Lockyrr proved, that in the amount 
“of spotted area of the sun also a 35-year period could be traced, 
“from 1833 till 1900, Brickner’s discovery surely has still gained 
“in importance”. 
Now, however, we can prove clearly, not only that the 35-year 
period, which Lockyzr thinks to be traceable in the solar phenomena, 
is ill founded — this was already pointed out by the author some 
years ago’) — but that the facts which have become known in 
the last few years have already shown that the English astronomer 
must be in the wrong. 
We will consider successively the two elements: (A) M—m (interval in 
time from a minimum to the next following maximum) and (B) 7.S.A., 
from which Lockyrr derived his period. For the reasons mentioned 
above, the magnetic curve can be left out of consideration. There is, 
of course, a relation between A and B. In general the intervals 
') Ep. Brückner, Klimaschwankungen seit 1700. Wien. Ed. Hölzel, 1890, p. 272. 
?) Jur. Hann, Handbuch der Klimatologie Bd I, 3e Aufl. (1908) p. 363. 
5) Dugors lc. p. 677. See also Supan, Grz. Phys. Erdk. IV Aufl. p. 232. 
4) G. Easton, Oscillations in the solar activity etc. Proceed. Amst. 26 Nov. 1904. 
p. 368, 
57 
