130 



However the variation of air pressure on Mount Pangerango will 

 not be wholly equal to that in the free atmosphere. 



The difference in phase for windcomponent and airpressure there- 

 fore is : 



at km. 20° 

 and „ 3 „ 9° 



As regards greater heights in the equatorial zone only the obser- 

 vations on the Misti top (5840 m. lat. — 16°16')*) are available. 



Here the phase for air pressure is 100° and for the wind 111° 

 (presuming that the wind here blows principally from the W.) 

 making a difference of 11°, i.e. quite in accordance with the value 

 obtained for the Pangerango. 



At the foot of the Misti the semi-diurnal variation of the air 

 pressure has a phase of 164° (Mollende 24 m) and on the top of 114°, 

 thus retarding 46° for a difference in height of 5.8 km. With regard 

 to the Pangerango and Batavia this retardation amounts to 18° for 

 a difference in height of 3.0 km., making per km. respectively : - 



a little difference, seeing the uncertainty in phase for the two 

 tops. The phase for the Misti has been calculated from one year's 

 observations and the one for the Pangerango from three years', but 

 only from two-hourly observations. 



If one may go by the value set up for the Misti, one may fix 

 the phase for airpressure above Java at 6 km. at 112°. This would, 

 however make a difference with the phase of the windcomponent 

 at 6 km. of 152°— H2°=40°, going by which, we should arrive at: 

 difference in phase of the semi-diurnal oscillation of wind and air- 

 pressure 



km. 20° 



3 „ 9 



6 „ 40 



and if still higher the phase of the air-pressure continues to decrease, 

 the difference will increase to 180° at about 10 km. 



This result therefore, gives no support to the reliability of our 

 results as to the renewed increase of phase of the windvariation 

 above 4 km., in so far that the difference of phase between the 

 variations of air-pressure and wind do not remain constant. On the 

 other hand this support is supplied by the observations of the 

 Ci-di-ift made at the Batavia Observatory during 1906 — 10. 



1) Hann, Sitz. Berichte Wien. Bd 118. 



