_Photographic Experiences._--We have received from our valued correspondent
DR. MANSELL, of Guernsey, a suggestion to which we are happy to give
publicity, and to the promotion of which we shall be very glad to lend the
columns of "N. & Q." Our photographic readers are probably aware that the
Talbotype process is increasing in favour; we have recorded DR. DIAMOND'S
strong testimony to its advantages. MR. LLEWELLYN has just described his
process (which is strikingly similar) in the _Photographic Journal_; and in
a recent number of _La Lumière_ the VICOMTE VIGIER confirms the views of
our countrymen. DR. MANSELL, who has given our readers the benefit of his
experience, well remarks that in all his acquaintance with physical
science, he knows nothing more remarkable than that MR. FOX TALBOT should
not only have discovered this beautiful process, but likewise have given it
to the world (in 1841) in so perfect a form, that the innumerable
experiments of a dozen years have done nothing essential to improve it, and
the best manipulators of the day can add nothing to it. It is, however,
with a view to testing some of the points in which photographers differ, so
as to establish which are best, that DR. MANSELL suggests, that a table
giving,
1. The time of exposure in the camera, in a bright May sun,
2. The locality,
3. The iodizement,
4. The maker of the paper,
5. The diameter of the diaphragm,
6. Its distance from the lens, and
7. The diameter, focal length, and maker of the lens,
would, if carefully and honestly stated by some twenty or thirty
photographers, be extremely valuable. Of this there can be little doubt,
and we hope that our scientific photographic friends, will respond to this
suggestion. We for our parts are ready to receive any such communications,
and will, at the end of the month, collate and arrange them in such form as
may best exhibit the results. It is obvious that, in a matter of such a
nature, _we_ at least should be furnished with the names of our
correspondents.
_The Céroléine Process._--The unfavourable state of the weather has
prevented me from making many experiments as to the value of the process
given in your 234th Number, but I have seen enough to convince me that it
will effect a great saving of trouble, and be more sensitive than any
modification of Le Gray's process that has yet been published. It will,
however, be rather more expensive, and, in the hands of persons
unaccustomed to chemical manipulations, rather difficult; but the solutions
once made, the waxing process is delightfully easy.