<;I;ANI> <>N --1,11 n.r i>.\ys 



TIII. i \\i.i.\i: 



T too* 403 



TABLE XX. Mean Values of Meteorological Element*. 



years 1890, 1899, and 1900. The last set of Kew results are deducible from 

 Table XLVI. of (A). The Falmouth data are from the tables in the annual ' Reports 

 of the Royal Cornwall Polytechnic Society.' They are deduced from the curves 

 given by self-recording instruments of the same pattern as at Kew. There are other 

 temperature data in the Falmouth Reports ; but they relate to thermometers in a 

 Stevenson screen and are less comparable with the Kew data. The vajKmr-pressures 

 and barometric heights in the table are in inches of mercury ; the temperatures are 

 in degrees Fahrenheit. 



The mean height of the barometer for the whole 12 years was higher than the 

 mean height during either the sun-spot maximum or minimum periods, and the same 

 phenomenon appeared at Kew whether the periods were those of case (a) or case (6). 

 Again, the mean vapour-pressure for the whole period did not differ from that for the 

 sun-spot minimum period by more than O'OOl inch either at Falmouth or Kew. Thus 

 in these two elements there is less evidence for a connection with sun-spot frequency 

 than might appear at first sight. As regards the mean daily range of temperature, 

 whilst all the differences are of one sign, they vary much in size, and the mean from 

 the 11 years 1890 to 1900 at Kew was smaller than that from either sun-spot 

 period in (b). 



18. In the case of the mean annual temperature, the long-j>eriod mean was 

 intermediate in all three instances between those for the periods of sun-spot maximum 

 and minimum, and the differences between these two latter means are fairly similar. 

 The existence of a difference between the average mean temperature of years of 

 sun-spot maximum and minimum is accepted as an established fact in HANN'S 

 ' Climatology.'* According to HANK'S figures the mean excess of temperature in a 

 period of four sun-spot minimum years over a period of four sun-spot maximum years, 

 situated relatively to maximum and minimum as in the case of the Falmouth groups 

 of years, is for a tropical station no less than 0'55 C., the difference between the two 



English Trnlation by WARD, p. 405. 

 3 F 2 



