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Notices to Correspondents.

J. M. G., _who writes respecting the Leigh Peerage, is informed that we
have a private letter for him. How can it be addressed to him?_

W. W. (Malta) _has our best thanks for his letter of the 25th of June. His
suggestion will be adopted; but we shall shortly have the pleasure of
addressing a_ private _communication to him._

SHAKSPEARE CRITICISM. _We have to apologise to many friends and
Correspondents for the postponement of their communications. As Soon as the
Index to_ Vol. vii. _is published, we shall take steps to get out of these
arrears._

C. P. F. _The_ Ch _in the name of _Ch_obham is soft. There is a _C_obham
within a few miles of the Camp._

IODIDE (June 24th). _There is much care required in iodizing paper; we have
no hesitation in saying at present the subject has not met with sufficient
attention. When the iodized paper is immersed in water, it is some time
before it assumes a yellow colour. This may be accelerated by often
changing the water. The brightness of the colour is by no means an index of
its degree of sensitiveness--on the contrary, paper of a bright yellow
colour is more apt to brown than one of a pale primrose. Too bright a
yellow would also indicate an insufficient soaking; and suffering the paper
to remain longer than is needful not only lessens its sensitive powers, but
does much damage by removing all the size._

H. N. (Kingston). _Violet-coloured glass, ground on one side, may be
obtained at 11d. per square foot of Messrs. Forest and Brownley, Lime
Street, Liverpool. It may also be had in London, but the price charged is
much higher. This glass obstructs just a sufficient degree of light, and is
most agreeable to the sitter; not much advantage accrues from the use of
large sheets, and it is objectionable for price. No doubt such an
application as you mention would be useful; but, from the difficulty there
is in keeping out the wet from a glass roof, it would be very
objectionable. Beyond a reference to our advertising columns, we cannot
enter upon the subject of the prices of chemicals and their purity. In
making gun cotton, the time of immersion in the acids must be the same for
twenty grains as for any large quantity: when good, there is a peculiar
crispness in the cotton, and it is_ quite _soluble in the ether. If our
Correspondent (who expresses so much earnestness of success) will forward
his address, he shall receive a small portion m