76 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 51 



If now it is assumed that p (the atmospheric pressure at the upper 

 level) has the same value in both equations, then by subtraction 

 there results: 



T Kli±=(h - M(2 vco cos if sin + V " 7 J . 



If in this we replace h — //„ by its value from (27) and the ratio 



p B 



, etc., by the ratio ° etc., from the recorded barometric readings 

 p B 



we have finally: 



B = ,b \1{ 2vCOCOS< o s * 6+ R')' 

 B \B 



For example, let B = 62o mm denote the reading of the barom- 

 eter on the Schneekopfe, B = 748 mm the corresponding reading 

 of the barometer at Breslau, the difference of level being about 

 i45o m ); also let v = 3o m , (the velocity of a violent wind storm), 

 and (p = 51 ; then by computation the exponent on the right of 

 equation (28) is found to be 



0.000 280 8 sin d -f 0.000 014 4. 



The extreme values of this exponent and the corresponding values 

 of B at the level of Breslau are as follows: 



mm 

 Exponent. B 



for = 90 (west wind); 0.0002952 747.958 

 for 6 = 270 (east wind) ; —0.0002664 748.037 



From this it follows that under the same circumstances in other 



respects, the pressure on the lower side of a stratum of air 1450 111 



thick, moving with a horizontal velocity of 30 m. p. s. and having 



an equal pressure at the upper side in the two cases will with an 



east wind be about o.o79 mm higher than with a west wind. If 



v 2 

 the term — had been neglected then for the west wind there would 



R? 



have resulted B = 747.960 and the difference between the west and 

 east wind would have been o.o8o mm . The influence of this term 

 is therefore very inconsiderable. 



Moreover the whole effect of the horizontal movements of the 

 air must be called very insignificant because a change of pressure 

 of 0.08""" ran scarcely be observed with our barometers. 



