2 Art. l.-T. Terîlda: 



is sufficiently rapid, the state can be maintained, since the flow is 

 partly hindered by the friction of the underlying layer and also the 

 deviating influence of the Coriolis's force. The irregularity of small 

 scale due to the influence of the immediate neighbourhood will be 

 gradually smoothed down as we proceed higher and higher, and 

 the influence of the remoter substratum will gradually come into 

 play. 



The above idea is not at all essentially new, being entertained 

 by the authorities such as Hann and Angot among others.'^ It 

 seems indeed otherwise impossible to account -for the irregular 

 nature of the geographical distribution of the diurnal components 

 as actually observed. As far as we are aware, there were however 

 as yet no serious attempt made to consider these effects of local 

 conditions a little more closely and to deduce anything in way of 

 finding some rules or laws from among the apparently intractable 

 chaos of materials. The present communication is the results of 

 some trials dared in tliis direction. Though far from laying an^^ 

 serious claim on the rigorousness of the method employed, nor on 

 the exhaustiveness of the materials utilized, the essential features 

 of some of the results given below may be of some interests for 

 meteorologists. 



2. The beginning of the present investigation dates back to 

 several years ago when the attention of the one of the author was 

 drawn })y the simple chart constructed by Buchan'\ showing 

 roughly the geographical distribution of the daily amplitude of 

 barometric pressure over the world. The dependency of the ampli- 

 tude on the distriljution of land and water was so conspicuous that 

 it seemed quite feasible to infer some quantitative relation between 

 the amplitude and the proportion of land and water over a certain 

 definite area. To carry out the comparison, the following procedure 

 was taken. The amplitudes of the pressure variation at different 

 points on the circles of latitude 20° and 40° respective!}' were 

 estimated from the chart by interpolation and plotted in a diagram 



1.) e. (/. Bürnstoin, Wiener Borichto, 113, 2a, 1904, p. 721 ; Met. Z.S., 7, p. 837. 

 2.) Buchan, Challen>fer Report, Phys. and Clieui. 2, Report on Atmospheric Circulation, 

 p. 21, Fii,'. 2. 



