am 



It appears, llipretbri', that Milan is situated out ol' tiie circle of 

 iiilliieiice, wliicli from a meteorological point of view is perfectly dear 

 because here the iiitkience of the Alpine montain chains and the 

 Mediterranean prevails, the equations (4) are, therefore, actually based 

 upon only four points, situated round Helder and the first equation 

 proves that these are sufficient to account for the harometric oscil- 

 lations in the central point to an extent of 94 "/o- 



As it may be assumed that this percentage would increase by 

 augmenting the number of stations, it appears from this equation 

 that local disturbances have only a subordinate intlnence. Whether 

 tliis statement is also applicable to the summer months can only be 

 proved by experiment. 



Another result is that the meteorological field cannot be considered 

 as uniform in different directions, the influence of (Jlermont being 

 twice as great as that of A^alencia at a slightly greater distance 

 from Helder. 



It may be, further, remarked that the central point, without 

 e.\ception, plays a more important part in the equations for the 

 sui'rounding stations than, inversely, the latter for Helder; which is 

 easily uiiderstood because the central point represents the meteoro- 

 logical conditions common to tlie whole field of disturbance. In the 

 partial c.c. this asymmetry disappears and for these quantities the 

 question arises whether and to what degree the relations are dependent 

 on the distance. 



Assuming that this relation can be taken as linear so that 



Q=l — kJJ 



where D denotes tlie distance, expressed in degrees and /■ a constant, 



we find for Valencia, Clermont and Christiansund for X,- respectively : 



0.0576 0.0560 0.0465 



for Neufahrwasser the somewhat different value: 0.0834. 



According to this relation the partial c.c. at equal distances of 5° 

 would be 



(>i, = 0.711 (1,3 = 0.720 (1,, = 0.583 9,, = 0.767. 



Finally the remarkable fact may be noticed that the same negative 

 correlation, observed between the region of the Azores and Iceland 

 at a distance of about 35°, appears to exist, and with the same 

 magnitude, between the stations Clermont and Christiansund at about 

 half the distance. 



5. In order to come to a conclusion concerning the results obtained, 



