PASSAGES. 



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notice of their approach by rising somewhat higher than its ordinary 

 standing, then falling gradually, the sky becomes overcast and lower- 

 ing, with much lightning in the northwest. On encountering a swell 

 from the northward, with these appearances, in the Indian Ocean, it 

 may be some indication that a storm is approaching; and all the 

 necessary steps should be taken to make ready for what may be ex- 

 pected in a few hours : if, however, the swell should be perceived 

 coming from the southward or westward, I think it may be considered 

 an indication that the storm has passed, and no apprehension need be 

 entertained. A recurrence of these storms, of any magnitude, seldom 

 takes place in the same season. 



The axis or centre of the storms of the Indian Ocean describe 

 an ellipse towards the southwest, in their onward course to the west, 

 the wind's veering being from left to right, instead of from right to 

 left. 



The storms which take place on the Avestern side of the South 

 Pacific, however, show another variation by their course being from 

 west to east, and the longest diameter of the ellipse being in a direction 

 northwest and southeast. These discrepancies I here point out, not 

 to controvert any of the ingenious theories which have been brought 

 forward, but simply to show that there are many facts connected with 

 these storms, which have not been as yet brought to light or fully 

 investigated. 



In navigating towards the Cape of Good Hope it is to be remarked, 

 that the longer a vessel can keep within the strength of the trade 

 wind, the greater is the probability of shortening the passage. It 

 will therefore be more advantageous to pass at other seasons than 

 those subject to hurricanes, nearer to the Mauritius and Bourbon. 

 From December to April is the season of hurricanes ; during the rest 

 of the year they do not take place : these islands then may be ap- 

 proached without apprehension. Yet in steering to the west, after 

 passing these islands, it is to be considered whether the coast of Africa 

 ought to be sighted, as calms and southwest winds prevail at the en- 

 trance to the Mozambique Channel, particularly during the summer 

 of the southern hemisphere. 



In passing the Cape of Good Hope with a view of stopping there, 

 the cold water on the Agulhas Bank will be entered. The use of the 

 thermometer in navigation is now well known and admitted ; had it 

 been known formerly, there is no place where it would have saved 



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