1871.] Proceedings of the Asiatic Society. 37 
If I strictly conformed to the custom which generally regulates 
the character of the presidential addresses in Societies such as this, 
I should, at this point, endeavour to set out in some detail the 
more remarkable steps of advance which have been taken in science 
during the past year. I refrain, however, from following the usual 
course for two reasons. Firstly, because our table is now so amply 
supplied with the Journals and Proceedings of the principal scien- 
tific bodies of the West, that any of our members can, by a glance 
at a few title pages, acquire a fuller knowledge of that which Lus 
lately been, and is now being done by the Savants of Europe and 
America, than I could convey to him with the labour of many hours, 
at the risk after all of passing over his particular subject of inter- 
est. Secondly, and indeed I may say chiefly, because I wish to 
avail myself of this opportunity for the purpose of pressing upon 
your notice with earnestness, though at no great length, a topic 
which I conceive to be of considerable moment to the interests of 
meteorological science throughout the world. 
Let me first, however, offer a few words of preface, for I do not 
assume that all, whom I desire to address, are conversant with the 
meteorological facts relevant to my object. 
We most of us know in a more or less general way that nearly 
all the more important atmospheric currents, 7. e. the persistent 
winds, gales and storms, owe their origin to the vertical displace- 
ment of air which, by reason of the sun’s action, is continually tak- 
ing place over a certain equatorial belt of the earth’s surface. I 
need not now describe the process (though it is well to remember 
that it is not perfectly simple) by which the air over this belt be- 
comes rarified and is caused to ascend. It is enough for my pre- 
sent object to remind you that the immediate consequence of this 
upward movement is a calm or rather comparative absence of 
horizontal motion in the air over the belt in question, an inflow of 
air along the earth’s surface from the direction of each pole to- 
wards and up to this belt and a corresponding ou/flow above, of 
the risen air from the belt towards the poles. 
The rotation of the earth introduces an apparent modification of 
these simple phenomena. If the surface of the earth were perfect- 
ly smooth, the relative course upon it of a free heavy particle, sup- 
