Mr. W. E. Birt on Atmospheric Waves, 



nn 



The barometric heights and coyTesj^ondlng winds, as shown on the 

 charts for each day, may he resolved into two sets, the intersecting 

 angles approaching more or less to light angles ; and these heights 

 and ivinds may be exhibited hi Tables showing the decrease or in- 

 crease of pressure from regions of high to low barometers, and the 

 reverse. 



Diurnal isobars, which are simply lines of equal pressure re- 

 sulting from existing natural arrangements, do not exhibit any 

 meteorological entity. To find such natural arrangements it is 

 necessary to resolve the isobars and wind-curves into their baro- 

 metric and anemonal elements. 



Table I. — Distribution of Pressure and Wind over the North- 

 west of Europe on April 19, 1873. Crest of S.W. wave pro- 

 bably near Valencia. 



First or highest zone below the crest. S.W. wave. 



Barom. 

 Valencia . . . 3018 

 Corunna . . . 2977 



Second zone below the crest. 

 Roche's Point . . 30-03 



Third zone below the crest. 

 Greencastle . . 30*09 

 Scilly .... 29-98 

 Biarritz .... 29-67 



Fourth zone below the crest. 

 Holyhead . . . 30*03 

 Pembroke . . . 30-03 

 Plymouth . . . 29*96 

 L'Orient . . . 29-87 

 Eochefort . . . 29-77 



Fifth zone below the crest. 

 Ardrossan . . . 30-08 

 Liverpool . . . 3003 

 Portsmouth . . 29-92 



Sixth zone below the crest. 



Leith 

 London . 

 Dover . . . 

 Cape Gris Nez 

 Paris 



Charleville . 

 Lyons . 

 Toulon . . 



30-05 

 29-91 

 29-83 

 29-82 

 29-82 

 29-80 

 29-69 

 29-63 



Direction. 



E.N.E. 

 N.E. 



S.W. wave, 



N.N.E. 



S.W. wave. 



N.N.W. 



N.E. 



E. 



S.W. wave. 



N.N.E. 



N.E. 



E.N.E. 



N.E. 



E. 



^.W. wave. 



N.W. 



N.N.E. 



N.E. 



S.W. wave. 



N.E. 



N.N.E. 

 N.N.E. 



N.E. 



N.N.E. 



E.N.E. 



N. 



N.E. 



Force. 

 4 

 6 



