TRANSACTIONS OF THE SECTIONS. 163 



the title of 'Physical Geography, in its Eelation to the prevailing "Winds and Cur- 

 rents,' by ]Mr. J. K. Laughton. A perusal of this book will show how wide is the 

 held embraced by this important branch of geogTaphical science, and at the same 

 time how much yet remains to be done before we attain to a satisfactory know- 

 ledge of those great movements of the ocean and atmosphere included under the 

 terms Gulf-stream, Equatorial cun-ent, Trade-winds, Monsoons, and so forth. 

 Mr. Laughton, in the book to which I allude, has called in question the accuracy 

 of the prevailing theories intended to explain these grand and, in some respects, 

 complex phenomena. The received hypothesis with regai-d to the ti'ade-winds, for 

 example, first outlined by Halley towards the end of the seventeenth century, but 

 developed by Hadley about fifty years later, and modified a few years ago by Maury, 

 he shows to be quite inadequate to explain all the facts of the case. Tliis hypo- 

 thesis, as is well known, assumes that the lower strata of the atmosphere near the 

 equator, being overheated by the sim's rays, expand and rise into the upper regions 

 of the aerial envelope, their place being taken by a cooler air, which rushes fi-om 

 the higher latitudes of the north or south, as the case may be ; and, moreovei', that 

 the ascending heated air travels backwai-ds, as an upper current, to the latitudes 

 where the cool wind originates, and then, descending again, the aerial circulation 

 is completed. One of the most striking objections made by Mr. Laughton to this 

 explanation is, that the equatorial zone is far from being the hottest part of ti'opical 

 and subtropical regions. He shows, as a matter of fact, in the North-Atlantic 

 basin, that the Great Desert of Sahara has a temperature from 20 to 50 degrees 

 hotter than the equatorial zone ; yet, so far from a cool current of ah" being drawn 

 in from the Atlantic towards this heated region, the north-east trades pass sti-aight 

 onward in their southerly com-se vrithout the slightest indraught towards the 

 African coast. He also shows that there is no proof of a vertical movement of the 

 air at the equator, or in the latitudes where the upper currents are supposed to 

 descend again. A multitude of similar or parallel instances are adduced fi-om other 

 parts of the eailh ; in fact nothing has more sui-prised me, in pei-usmg the work, 

 than the great amount of reading and research the author has applied to the eluci- 

 dation of this and kindred problems. 



Having shown the untenability of the received hypothesis, he modestly advances 

 a new one of his own. This is difficult, perhaps, to explain in a brief manner ; 

 but he shows, from the most varied evidence, that the general movement of the 

 atmosphere over the whole earth is from west to east, and that in regions where 

 the prevailing winds at the earth's surface are not westerly, an upper and 

 strong westerly movement exists above the lower winds. The trade-winds, mon- 

 soons, and all other partial atmospheric movements, he shows to be chiefly eddies 

 and reflected cm-rents of greater or less constancy ; and he confirms this supposition 

 by an exhaustive examination of the laws of movement of air and other fluids. I 

 may say, in short, that even those who may not agree with the author's reasonings 

 will find both pleasure and profit in studying the rich store of observation and lucid 

 argument contained in this little work. 



Among the many interesting papers which will be read before you during the 

 present Meeting, I may announce two, on subjects of great general interest, by 

 General Sir Henry Eawlinson — one on the Site of Paradise, and the other on the 

 River Oxus ; both the fi-uits of long study and research, and sure to be listened to 

 with the attention that every thing emanating from so distinguished a geographer 

 and philologist so well deserves. An important communication from Dr. George 

 Campbell on the Physical GeogTaphy of British India is also expected, a subject 

 which has been for yeai's a special study of the author, dming his residence in a 

 high oflicial position in India. Mr. T. T. Cooper, a ti-aveUer who has distinguished 

 himself by his persevering endeavours to ti-averse the diificult country between 

 Western China and our Indian possessions in Assam, will read a paper on Eastern 

 Thibet, in which he will dilate on the commercial bearings of his explorations, 

 which were undertaken with a view to discover a route for an overland trade 

 between the populous and productive regions of the Yang-tsze-Kiang in China and 

 the equally rich and densely populated plains of British India. 



With regard to Afi-ica (that great continent which still continues the principal 

 field of geogi-aphical enterpi-ise), I have to announce that Mr. Winwood Reade, 



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