

Inaugural Lecture 1889 7 



obstacle to the salvage operations except the physical conditions 

 under which the explorer had to live. It is difficult to re 

 the great change of condition which this diver's body had 

 to endure every time he descended to his work from an atmo- 

 sphere equivalent to a column of 30 inches of mercury to one 

 equivalent to 15 feet of the same metal. Every inhalation 

 in his diving dress supplied oxygen for the combustion of 

 his tissues, five times greater than that taken in at the surface. 

 No wonder then, that though he recovered the treasure, half 

 nf which was to be his, he died of his exertions. The extent 

 to which submarine regions can be personally explored is thus 

 so limited as to be negligible, and we have to trust for our 

 information to the indications of instruments and the collection 

 of specimens. It need hardly be added that our knowledge 

 of the solid land underlying the ocean is still more restricted, 

 being limited to the few inches of thickness which can be 

 penetrated by the sounding tube or scooped up by the dredge, 

 and it is unlikely that it can ever be directly extended to anv 



tter depth. 



But while the explorer of the ocean labour^ under the dis- 

 advantage that he cannot penetrate into its interior, he has 

 this compensating advantage that he can freely traverse 

 urface in every region and place himself vertically over 

 v point of the three-fourths of the surface of the solid 

 nlobe, which is covered by water, and explore it in detail 

 from the bottom to the top to an extent limited only by the 

 imental means at his hand. 



This method nf, and field for, research was unknown or 

 neglected until about thirty years ago. On looking back 

 it seem- almost incredible that tlie men of all nation- hiirnini; 

 with -< ientific and exploring zeal -honld have entirely < 

 looked and apparently dospi--d tin- large portion of the world. 

 so a< and so easy of exploration, and have inn: 



'ulablr hard-hip- and dangers in the exploration of 

 inhospitable deserts, fever-stricken junior- and inavr iM<- 

 mountain top^. If they did turn thnV eyes toward- th< 

 they did not allow them to rest on what was before the door, 

 on the I oceans traversed in th- ordinary course of 



