ATMOSPHERE OF GREAT BRITAIN AND ON THE CONTINENT. 



663 



the air was damp and wet-bulb depression under 4° the value of C is nearly the same as 

 that obtained from the Kingairloch and Alford observations ; and at the other wet-bulb 

 depressions the differences are not great, as will be seen from the following table, in 

 which are arranged the different values of C at the different wet-bulb depressions 

 obtained from the observations taken at the different stations. 



Table XXII. 



Place. 



Values of C at different wet-bulb 

 depressions. 



2° to 4° 



4° to 7° 



7° and over. 



Kingairloch, 1893 ..... 



1892 ..... 



Alford ...... 



Rigi Kulm ...... 



77,525 



No observations 



75,474 



75,176 



105,923 



116,677 



95,153 



104,430 



140,628 

 174,832 

 124,921 

 124,211 



Mean 



76,058 105,545 



141,148 



It will be noticed that the Kingairloch values for 1893 are very near the mean, and 

 the observations at that station are the most trustworthy. 



I must admit that the figures in the table appear to agree far too well. Accident 

 must have assisted greatly in bringing out so close an agreement as above indicated. I 

 may, however, state that no efforts have been made, while selecting the observations for 

 the tables, to bring about this agreement ; all the suitable observations were used. The 

 figures are exactly as they were first entered in their different tables. Only two or three 

 alterations were made when revising them, and before any calculations were made. 

 From the great differences in the values of C in the different observations, it is evident 

 that the close agreement of the final values at the different wet-bulb depressions must be 

 very much accidental. The conditions, and the small number of observations in each 

 table, show that this must be so. There are, however, the Callievar observations, which 

 are far from agreeing with the others, and warn us of probable errors in the value of C. 



Dust and Sunshine. 



We have seen from the Kingairloch observations that there was an extraordinary 

 increase in the number of particles when the sun was shining and N.W. winds blowing, 

 and we naturally turn to the Alford observations to see if we have in them any 

 confirmation of this phenomenon. We however look in vain for any such abnormal 

 increase under any conditions with sunshine at Alford, all the high numbers there 

 being due to southerly winds. In Tables L, II. and III. will be found many days on 

 which the sun shone and the numbers remained low all day. It is possible there may on the 

 average have been a slight increase with sunshine, but if there was, it was slight, and might 



