THE ANTI-TEADES OK PASSAGE WINDS. 



193 



pictured on our 8 a.m. chart. The reader will do well to study the remarks 

 published in the Quarterly Weather Eeport for February 4th to the 7th, as 

 well as its Plate VIII. There it is shown on page 10 how at 8 a.m. of the 

 6th, " neither the daily chart nor the barograms showed any very serious 

 sign of disturbance." On page 11 there is the following remark : " The 

 facts appear to show that the gale which ensued on our coast was to the 

 full as much to be attributed to the advance of the high pressure Westward 

 from Eussia, as to that of the low pressure Eastward from the Atlantic." 

 The isobars on our charts for the 6th, 7th, and 6th, seem to prove the force 

 of this remark. 



Whatever may be the cause of these areas of lowest pressure, the five 

 diagrams which follow the charts, as well as a large number of others 

 received from the commanders of steamers to and from America, who are 

 observing for this office, show that very many of them are experienced in 

 the Atlantic, and the difference between the barometer curves of outwarc? 

 and homeward bound steamers, as well as the extracts from logs, show 

 that they are travelling to the North-Eastward. 



Normal state of Atmospheric Pressure and Wind between England and 



North America in Winter. 



Undulations of Barometric Pressure moving 30 to 40 miles an hour to the 

 North-Eastward, with their accompanying Winds. 



We have, then, two important facts : 1. By consulting Buchan's Isobars, 

 we ^nd that during the winter months the normal state of pressure is high 

 over the land on each side, and low over the sea in the central part of the 

 Atlantic, also that the pressure gets lower as you go North from the Azores. 

 Let the line A B C in the diagram above be supposed to represent a section 

 of the normal state of pressure across the Atlantic, with a lower pressure 

 to the North than to the South of it, then the arrows may be supposed to 

 represent the normal direction of the wind. 



2. Besides this normal state, we have, as it were, the crests and hollows 

 of waves of pressure moving to the North-Eastward. These (the diagrams 



N. A. 26 



