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uninterrupted course over a wide and unbroken extent of 
ocean, the unvarying direction and perennial nature of the 
N.E. and S.E. trade winds appears to prove the fact of a 
constant flow of air from the poles towards the equator. On 
their approaching the equator, these winds, as might be an- 
ticipated, enter a zone of frequent calms, and are lost. This 
constant supply of air, poured from both poles towards the 
equator, must find vent in some way ; and while running 
down the N.E. trade winds on a voyage to India, I have 
repeatedly observed, through the intervals of the lower 
clouds, detached thin ones moving at a great elevation 
towards the north, and directly against the course of the 
trade winds and of the much lower but heavier stratum of 
vapour carried along with them. 
At the changes of monsoons, the opposite winds are found 
charged, respectively, with negative and positive electricity, 
and heavy storms of thunder and lightning result on their 
meeting ; and the same is observed in a minor degree when 
easterly and westerly winds meet. Magnetism, so powerful 
in the higher latitudes, is weakened towards the equator ; 
and if it may be inferred that, in like manner, the positive 
electricity brought by the atmosphere from the poles is dis- 
charged on approaching the equator and becomes negative, 
an explanation would be afforded of the cause and nature of 
the aurora borealis. 
This is distinctly given as his opinion by the late Admiral 
Fitzroy, in his report of 1864, on the Polar and Equatorial 
Air Currents* 
* “We have also found the telegraph wires much disturbed when these 
main (principal) currents were beginning to act positively in force. No great 
tempest — no heavy polar or tropical gale has occurred here since 1860 
without more or less ‘ wire disturbance ’ (as the telegraphists say) ; and I am 
led by these, with other concomitant facts, and examination of numerous 
sea records, as well as registers on land, to believe that such electric effects 
are caused by atmospheric collision, and that c magnetic storms' sedulously 
watched now at many observatories, are results of atmospheric storms, 
