A STUDY OF CORRELATIONS AMON(J TERRESTRIAL TEMPERATURES. 387 



in the method of investigation. The methods of treatment are different in that 

 the present work includes only regions of low or middle latitudes, while those chosen 

 by Langley include northern regions also, especially Siberia. Thus a seeming dis- 

 cordance in the course of any one year is not surprising. I have not made a careful 

 comparison of the two results except in the most striking case. The most important 

 decade of comi^arison in the work is the first of 1903. The Dekadenberichte show an 

 extraordinary rise of temperature during this term, while by reference to Table XII, 

 1903, of the present work, it will be found that the general mean deviation here found 

 is only + 0°.5. Considering this decade individually the evidence afforded by the 

 Dekadenberichte is vastly more complete for the world at large. The positive departure 

 was best marked in European Russia and Siberia, reaching its maximum at Orenburg, 

 where the temperature was 12°.l C, or more than 20"^ Fahr. above the normal. But 

 it covered the whole of Europe, Scandinavia excepted. Now, these regions I have 

 mentioned are not included in the present work because the effect of any admissible 

 change in the sun's heat on their temperature would be very slight through a ten-day 

 term, especially in January. Although the general mean for the equatorial region is 

 positive, it is not at all accented as in the wider range of regions used by Langley. 



For our present purpose the important question is whether we can attribute this 

 remarkable rise of temperature to an increase of the solar radiation. The reply is that, 

 if there was such an increase during the decade in question, its effect would have been 

 felt mainly in the equatorial regions, and but slightly in northern Europe and Siberia. 

 We therefore conclude only that great fluctuations of temperature occur which we 

 cannot attribute to changes in the sun's radiation, because they do not extend to 

 the regions where such changes would have their greatest effect. 



