THE 



GEOLOGICAL MAGAZINE. 



NEW SERIES. DECADE III. VOL. VII. 



No. X.— OCTOBER, 1890. 



OZRIGKEIDT.A.L ABTICLBS. 



I. — On Variations of the Climate. 



By Dr. Edw. Jaderin, 



of the Royal Swedish Academy of Sciences. 



HOW often do we not hear old people assert that when they were 

 young the climate was cpiite different ; that the weather was 

 warmer or colder, etc. ; and even comparatively young people are 

 sometimes of the same opinion. It is most natural to assume that 

 these observers have been misled by the more intense impressions 

 of youth, which cause, for instance, a hot summer, bringing with 

 it more rural pleasures and open-air sports, to be engraved on the 

 mind for life. On the other hand, should the early years be accom- 

 panied by much wet weather and storms, these years are perhaps 

 more easily forgotten, as the monotonous and tedious life within 

 four walls to which one is then confined does not leave that distinct 

 impression upon the youthful mind as that of a glorious summer 

 spent out-of-doors. However, the importance of the question and 

 its great genei'al interest demand an investigation of the problem ; 

 the more so as certain scientific theories and hypotheses tend to 

 prove that a change in the climate must necessarily take place. 



If we assume for a moment that the observations just referred to 

 really were correct, and that besides — as many people also believe — 

 the change, for instance a fall of temperature, steadily continued 

 generation after generation, it will easily be seen that this assump- 

 tion would lead to absurd results. For, in order to be noticeable in 

 one generation the fall of temperature should at least amount to 

 1° C, but 1°, say in fifty years, makes 20° in a thousand years, or 

 40° from the birth of Christ to the present time. If in reality the 

 temperature during these 2000 years has been slightly lowered, the 

 difference cannot, according to the testimony of history, be very 

 considerable, and must, during a generation, be absolutely unnotice- 

 able. Therefore the change which it is assumed has taken place 

 must — if there be any — be periodical, i.e. that warm and cold periods 

 of varying degree altei'nate. Indeed, to this conclusion — and a 

 very important one — our experience is led from every-day life. 

 But further than this we are unable to proceed without a systematic 

 scientific basis for our research. 



For a long time geological investigation has demonstrated that 

 the climatic conditions of the earth during earlier geological periods 



DECADE III. — VOL. VII. NO. X. 28 



