INTEODUCTION. Xlll 



and of whatever there may be of general interest in its commercial 

 uses or industrial pui'suits ; — for all such things pertain to this de- 

 j)artment of science. 



The object of this work, moreover, is to show the present state, 

 and, from time to time, the progress of this new and beautiful 

 ^system of research, as well as of the advancement made in this 

 interestmg department of science ; and the aim of the author is to 

 present the gleanings from this new field in a manner that may be 

 interestmg and instructive to all, whether old or young, ashore or 

 afloat, who desire a closer look into "the wonders of the great 

 deep," or a better knowledge as to its winds, its adaptations, or its 

 Physical Geography.* 



The results that are embodied in Plate I. alone of this edition 

 would, had the data for it been collected by a force specially employed 

 for the purpose, have demanded constant occupation from a fleet of ten 

 sail for more than one hundred years. The co-ordinating of these 

 observations after they were made, and the bringing of them to the 

 present condensed form, has involved a vast amount of additional 



* There ia an old and very rare book wliicli treats npon some of the subjects to 

 which this little work relates. It is by Count L. F, Maesigli, an Italian, and is 

 called Natural Description of the Seas. The copy to which I refer was trans- 

 lated into Dutch by Boerhaave in 17SG. 



The learned count made his observations along the coast of Provence and Tjan- 

 guedoc. The description only relates to that part of the Mediterranean. Tlie 

 book is divided into four chapters : the first on the bottom and shape of the sea ; 

 the second, of sea water ; tlie third, on the movements of sea water ; and the 

 fourth, of sea plants. 



He divides sea water into sin-f:ice and deej^-sea water ; because, when he makes 

 salt from surface water (not more than half a foot below the upper strata), this 

 salt will give a red colour to blue paper ; whereas the salt from deep-sea water 

 will not alter the colours at all. The blue paper can only change its colour by 

 the action of an acid. The reason why this acid (iodme?) is found in surface and 

 not in deep-sea water is, it is derived from the air ; but he supposes that the salt- 

 l^etre that is found in sea water, by the action of the sun's rays and the motion of 

 the waves, is deprived of its coarse parts, and, by evaporation, embodied in tlie air, 

 to be conveyed to beasts or plants for their existence, or deposited upon the 

 earth's crust, as it occurs on the plains of Hungary, where the earth absorbs so 

 much of tliis saltpetre vapour. 



Donati, also, was a valuable labourer in this field. His inquiries enabled 

 Mr. Trembley^ to conclude that there are, " at the bottom of the water, moun- 

 tains, plains, valleys, and caverns, just as upon the land." 



But by far the most interesting and valuable book touching the physical geo- 

 graphy of the Mediterranean is Admiral Smyth's last work, entitled " The Me- 

 diterranean ; a Memoir, Physical, Historical, and Nal'tical. By Kear- 

 Admiral AVilliam Henry Smyth, K.S.F., D.C.L.," &c. London : John W. Parker 

 and Son. 1854. 



> Philosophical Transactions. 



