238 



NATURE 



[Jan. 29, 1874 



coming election ; for his principles of action are under- 

 stood ; his views with regard to the Universities and the 

 higher teaching generally are known ; and his unwilling- 

 ness, even to consider the desirability of raising the 

 salaries of the scientific cfficers of the Biological De- 

 partment of the British Museum to the level of those of 

 ordinary Government officials is before the world. There 

 is no doubt that he has forfeited all claim, either to the 

 support of the Scientific or the Medical Graduates of the 

 important Corporation which he represents. 



PHYSICAL GEOGRAPHY 



Phf steal Geography, in iU Relation to the Prevailing 



Winds and Currents. By John Knox Laughton, M.A., 



F.R.A.S., Mathematical and Naval Ins ructor at the 



Royal Naval College. Second Ed. (J. D. Potter, 1873.) 



The Ocean : its Tides ana Currents, and their Causes. 



By William Leighton Jordan. (Longmans, 1873.) 

 HP HE first part of Mr. Laughton's work consists of a 

 comprehensive and valuable summary of the pre- 

 sent state of our knowledge of the prevailing Winds in 

 different parts of the globe ; on the basis of which he 

 proceeds to examine into the commonly-received theory 

 of Atmospheric Circulation, and pronounces that " it de- 

 scribes the phenomena which do not exist, and misrepre- 

 sents, or does not account for, phenomena which do." 

 The second part treats of the Currents of the Ocean ; 

 and these (following Major Rennell) he attributes for the 

 most part to the winds prevailing in the localities in 

 which they originate, their effects being variously modi- 

 fied by coast-lines, the meeting of other currents, &c. 

 We believe that he is quite justified in upholding this 

 general doctrine, and in repudiating the notion of Captain 

 Maury that differences of temperature, excess of evapo- 

 ration, &c., can sustain the Gulf Stream or any great 

 oceanic current. But he rides his hobby a great deal too 

 hard, when he affirms that under no circumstances can 

 these agencies produce currents ; going so far as to 

 attribute the in-current of the Strait of Gibraltar to the 

 7fis-a-tergo of the Gulf Stream. As v.ell might he attri- 

 bute to it the constant current which sets over the bar of 

 the Karaboghaz or Black Gulf on the eastern side of 

 the Caspian, and carries (according to the computation of 

 Von Bar) 350,000 tons of salt a day into this great natural 

 salt-pan, the water (which the natives fancy must have 

 some subterranean outlet) being all got rid of by evapo- 

 ration. According to Sir John Herschel's computations, 

 the excess of evaporation from the Mediterranean area, 

 over the return of water by rain, would require twelve 

 NtIcsXo supply it ; and as there is only one Nile, and as 

 Captain Wharton's recent researches in the Dardanelles 

 show that the Black Sea sends very little of its river- 

 water into the Mediterranean (the supply poured in by 

 the Danube, the Don, the Dnieper, and the Dniester, 

 being very little more than sufficient to make up for the 

 evaporation of the Black Sea itself), it is obvious that an 

 enormous deficiency must exist, after every allowance has 

 been made for the Rhone, the Ebro, and the Po, which 

 are the only considerable rivers, beside the Nile, that 

 pour their waters direct into the Mediterranean basin. 



Mr. Laughton does not seem to have made himself as 

 well acquainted as a Government naval instructor might 



have been expected to be, with recent ccntributions to 

 Oceanic Hydrography. Thus he repeats the statement of 

 his first edition, that the Gulf Stream rushes through the 

 Florida Channel at a rate varying from 80 to 120 miles a 

 day ; whereas the Admiralty Pilot Chart, based on the 

 most trustworthy information, makes the annual average 

 only 48 miles per day. He does not deign to notice the 

 arguments adduced by Dr. Carpenter in his last report to 

 the Royal Society, which have satisfied many eminent 

 authorities that the amelioration of the climate of North 

 Western Europe is due, not to the ti ue Gulf Stream or 

 Florida Current, but to a slow noith-easterly movement of 

 warm water sustained by thermal influences alone. He 

 repeats (p. 200) the old fallacy that the cold of the ocean- 

 bottom is " due to the great depth, to the impermeability 

 of water by the sun's rays ; " as if this had not been dis- 

 proved by the fact, that the bottom-temperature of the 

 Mediterranean, at depths ranging to 2,000 fathoms, is 

 from 54° to 56°, whilst that of the Atlantic at similar 

 depths and under the same parallel is twenty degrees 

 lower. And in p. 250 he makes the astounding statement 

 that " the gradual closing up of the channels [through 

 which the Gulf Stream flows], by the ceaseless work of the 

 polypes, has, l>y diminishing the outlet, increased the force 

 of the stream ;" which is tantamount to saying that the 

 stream of water which issues from a fire-engine has a 

 greater force than that which works its pumps ! If we 

 had only to narrow an outlet to create force, we need not 

 be afraid of the exhaustion of our coal. 



We recommend Mr. Laughton, before he issues another 

 edition of his book, to dismiss from his mind, if he can, 

 all prejudice in favour of his particular theory, and to 

 open his mind more fully to the evidence of a vertical 

 Oceanic circulation, which he already partly admits, and 

 which is not in the least inconsistent with his fundamental 

 principle (in which we entirely accord) of the maintenance 

 of the /;c;7>(7«/(7/ circulation of the great Ocean-basins by 

 the movements of the atmosphere. 



The title of Mr. Jordan's book is very misleading ; for, 

 although professing to treat of the tides and currents of 

 the Ocean, he devotes the greater part of his 344 octavo 

 pages to an exposition of what may be called the Jor- 

 danian (in opposition to the Newtonian) system of Astro- 

 nomy. This system is based on the doctrine of inertion, 

 by which Mr. J. means the inherent tendency of all mo- 

 tion to come to an end. The only motor force he admits 

 is that of gravitation ; and he considers himself to have 

 proved that the revolutions of the planets round the sun are 

 due to the opposition between solar gravitation and astral 

 gravitation, " so that, in their courses, they are borne 

 smoothly along the lines of equilibrium lying between 

 opposing forces of gravitation." He also maintains that 

 " the rotation of a sphere tends to cause surrounding 

 bodies to revolve around it ; " and that, in this manner, 

 the rotation of the earth from west to east tends to carry 

 the moon in the same direction, its "lagging behind" 

 beng due to " astral gravitation." 



The apphcation of Mr. Jordan's theory of inertion to 

 the movements of the ocean is very obvious. Reasoning 

 upon the fact that when a vessel containing water is 

 made to rotate, "the water tends to maintain its posi- 

 tion, and therefore has a relative motion over the surface 

 of the vessel in the opposite direction to that in which 



