iv THE OCEAN WORLD. 
With the faint hope that I would have no difficulty in 
simply retaining the text that helps to explain the in general 
excellent woodcuts that illustrate the present volume, I 
undertook to revise it. Those familiar with the subject will 
perhaps appreciate the statement that, as it proved, it would 
have been an easier and certainly a more pleasant task to 
have re-written the work. Those who will compare the 
present edition with that of 1869, will see that the alterations 
in this one have been very numerous and important, several 
chapters being nearly re-written; that all the dogmatic asser- 
tions, so striking in the edition of 1869, have been toned down 
in conformity with that modesty that should characterise the 
searchers after truth; and that the more rampant twigs of 
French eloquence have been pruned in conformity with our 
quieter if not better taste. Would that I could add that they 
will also find all errors corrected, but of the contrary I am 
painfully aware. At the same time, I believe the candid 
critic will see that if in this matter I have not done all I 
should, I have at least, under all the circumstances, done all 
I could. 
I am indebted to my friend, G. J. Stoney, M.A., F.R.S., 
for the short account of the cause of the tides, to be found 
on pages 32 to 35. Perhaps never before has the subject. 
been treated in a more popular and yet scientific a way. 
November 1, 1872. E. P. W. 
~ 
