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XII. On Deep-sea Easplorations. 

 By Professor W. P. Trowbridge*. 



OUR present knowledge of the depth of the sea m all quarters 

 of the globe may be compared to the ideas which existed 

 in the minds of men with regard to the form of the continent 

 of America, after the first voyages of the old Spanish and English 

 navigators. Previous to the discovery of Columbus, the most 

 exaggerated notions were entertained of the boundless extent, 

 the unfathomable depths, and the dark wastes of that great chaos 

 of waters which no man had yet dared to explore. 



The discovery of the great navigator was quickly followed by 

 the explorations of Ponce de Leon, Cabot, and others, who 

 touched upon various points of the unknown land, and bore 

 back to the old world trophies from the new. Many of the charts 

 made by these bold mariners are still preserved as memorials 

 of their achievements ; but what a contrast do they present to 

 the maps of the present day ! in most of them scarcely a resem- 

 blance can be traced to the form of the continent which we now 

 inhabit. The world does not cease to honour these adventurous 

 pilots because their first eS'orts were not entirely successful : 

 subsequent researches, with the help of continued improvements 

 in the art of navigation, and in astronomical science, corrected 

 their errors without detracting from their merits. But while 

 these vague notions with I'egard to the superficial extent of the 

 sea have been removed, and its surface measured with all desir- 

 able accuracy, the veil of mystery still obscures its depths. The 

 bottom has been reached at various points ; and the world has 

 just witnessed the wonderful stride in human progress to which 

 the first movements in this new field of scientific investigation 

 have led. It is therefore legitimate now to review what has 

 been done, — not with a view of criticising the works of those 

 who have been foremost in these discoveries, but with the better 

 motive of seeking for truth, and stimulating to renewed efforts 

 those who have already done so much, by suggesting probable 

 causes of error in the results which have been obtained, so that 

 new methods may be devised, if necessary, for establishing, with 

 the certainty which science and tlic popular mind now require, 

 the true form of that portion of the solid crust of the earth 

 which lies concealed beneath the waters of the ocean. 



Tlic question of the character of the thin covering of the bot- 

 tom has undoubtedly been settled by the examination of speci- 

 mens brought to tlie surface. And here we must digress some- 

 what, to refer to the labours of those who were first instrumental 

 in inaugurating deep-sea explorations. 



* From Sillimaii's American Jouniiil for November 1858. 



Phil. May, S. 4. Vol. 17. No. 1 13. Feb. 1859. II 



