3. In his second edition, 1823, Nelson says, "The present stone was set up in 1821, by the trustees of the parish ways." This is the stone which has lately been removed.

H. G.

PHOTOGRAPHIC CORRESPONDENCE.

Photographic Experience.—I send you the Rev. W. Le Mottée's and mine:

W. Le M.
1. 6 minutes' exposure.
2. Sea-side.
3.

Iod.—Double iod. sol. from 25 gr. N. A. to 1 oz.
Exc.—5

50 gr. A. N. A. 5

G. A. Aq. 2 drs.
Dev.—1o 50 gr. A. N. A. and G. A. part. æq. 2o G. A.
4. Turner.
5. ⅜ inch.
6. 3 inches.
7. Diam. lens 3 in. Foc. length parallel rays 12¾ in.Maker, Slater. Picture 8½ x 6½.

T. L. M.
1. 10 minutes.
2. Sea-side.
3.

Iod.
Exc. As Le M.
Dev.
4. Turner.
5. ⅜ inch.
6. 3⅛ inches.
7. Diam. lens 3¼ in. Foc. length 17½ in. Maker,Slater. Picture 11½ x 9¼.

I have given the development according to the plan usually followed, for the sake of comparison; but where it is desirable to work out the shadows fully, it is far better to give longer exposure in the camera (three times that above given), and develop with gallo-nitrate of the strength used to excite, finishing with gallic acid. The time varies with the subject; a cottage among trees requiring 12 to 14 minutes. Almost all the statements I have seen, giving the time, do so absolutely; it is well to remind photographers, that these convey no information whatever, unless the focal length for parallel rays, and the diameter of the diaphragm, are also given: the time, in practice as well as in theory, varying (cæteris paribus) directly as the

square of the former, and inversely as the square of the latter; and, without these corrections, the results of one lens are not comparable with those of another.

When shall we get a good structureless paper? The texture of Turner's, especially his new paper, is a great defect; and its skies are thin, very inferior to the dense velvety blacks obtained with Whatman's of old date—a paper now extinct, and one which, unfortunately for us, it seems impossible to reproduce.

T. L. Mansell.