The establishment of the formula and the determination of 

 the mean figure resulted from the following procedure: the limits 

 of tluctuation were March 20 th and April 24 th i. e. a difference 

 of 36 days; of this the half is 18 days; if we reckon 18 days 

 from March 20 th , April 7 th is obtained as mean date. 



In accepting the two extreme dates March 20 th and April 24 th - 

 1 took care that every intermediate date should be represented and 

 that consequently every date should be taken into consideration, in 

 making the calculation. 



I would merely remark here that the country mean figure, as 

 phaenologically established by our Meteorologist J. Hegyfoky in 

 ,,Aquila" vol. XI. 1904 on the basis of 10,053 recent data, is also 

 April 7 th . 



RECENT DATA FROM 1890. 



Observation inaugurated on the occasion of the Congress. 

 Formula drawn from the data of Ornithologists 1890. 



Earliest arrival: 15 th March, Horgos (87 m. above s. 1, plain). 



Latest arrival: 15 th April, Zuberecz (700 1300 m. above s. 1, subalpine). 



Difference : 32 days. 



Mean date: 30 th March 



Regarding this mean it is to be remarked that it is based upon 

 the records of 1 7 stations only, but the influence of height is obvious. 



Formula based on the data of the Royal Forestry Offices 189(1. 



Hypsometrically : 



Earliest arrival : Szeged 18 th March, 84 m above s. 1., plain. 

 Latest arrival : Dames 21 th April, 1328 m. above s. 1., alpine. 

 Difference : 35 days. 

 Mean dale : 5 April. 



Geographically : 



Ogradena. southernmost: 19 th March, 44 40' N.L. 

 Turdossin, northernmost: 8 th April, 49 2 ' N.L. 

 Difference : 21 days. 

 Mean date: 30 th March. 



It appears, therefore, that the mean date calculated upon the 

 hypsometrical elements, furnished by a fairly reliable system yield 

 a mean figure 5 th April - which comes very near the country 

 mean figure 7 th April. The geographical elements, however yield a 

 widely divergent mean figure : the 30 th March. The reason is that 



