d e d ic a t io n .
devotion of your time and your money to the advancement
of Natural Science, and the deep love
with which yon are evidently inspired for the works
of Creation, have impressed me with a strong respect
for your character, and singled you out as the individual
with whose name I should particularly desire
to associate this Work.
I would therefore beg of you to accept of its
dedication, and believe in
The high consideration and esteem of
Yours most sincerely,
T H E A U TH O R .
P R E F A C E .
W h il e the Preface forms the first p art of every work, as
the name implies, and precedes always the descriptive matter,
it IS as invariably the last Avhioh is written, and the last often
to be read.
Nevertheless there are few portions of a work the endit-
ing of which is undertaken with more alacrity than the
writing of this same preface — the author’s mind being
cheered by the near prospect of the completion of his task —
it may be of a difficult and an arduous task — in which the
obstacles to its successful issue Avere many, and the result problematical,
and the hope of a suitable reward in recompence
of his toil either in the form of approbation, if deserved, or
money, should the undertaking be of a sufficiently popular
character to lead to so substantial a termination.
There is also another reason which renders the writing of
the preface an agreeable occupation. I t is the opportunity
which it affords, to the writer to render to those who have
aided him in his enquiries the acknowledgments which their
liberality and their kindness so strongly claim.
To Sir W. J . Hooker, Dr. Greville, Mr. Borrer, Mr.
Harvey, and the Rev. M. J . Berkeley, names prominently
inscribed in the records of the successful cultivators of natural
science, the pursuit of which is the most peaceful and the
most pleasant of all employments, I am deeply indebted.
The two former gentlemen liberally placed at my disposal
their valuable collections of freshwater Alga, and Mr. Harvey
and Mr. Berkeley communicated to me numerous unique
specimens accompanied by valuable remarks.