PREFACE
v
much kindness and assiduous care in my own personal
requirements of this kind. Such apparatus, to express
it briefly, is described here not as their apparatus, but
as being in greater or less degree my apparatus, by
contrivance, or selection, or modification, or personal
connection with it in some way or other, even when not
(as frequently the case) planned in the first instance for
my own use.
But while it is best to state this quite simply, it will
I trust be found that, beyond what thus became
unavoidable as forming part of that very experience
which is the basis of the whole, the subject has been
treated so as to be of most use to all, and without
any prejudice to other optical workshops of well-known
character with which I do not happen to have been
brought into the same personal contact. Except a very
few articles or details which may be patented in various
quarters, and which are well known to the trade and
readily obtainable from the various manufacturers, the
apparatus and arrangements here described are free to
all. It is perfectly open to any reader to have them
constructed by whom he chooses, with any improvements
he can suggest ; while it is equally open to any optician
to construct them as excellently, and sell them as
cheaply—or the other way if he prefers—as he possibly
can.
I need only add to this explanation, that in the
following pages the first person singular has been pur¬
posely adopted, as more simple and less really egotistic in
a book of such necessarily strong individuality, than any