Nor is it essential that perfect horizontality or parallelism of the cameras should be maintained in copying trees. For buildings, however, it is absolutely necessary that the cameras be kept straight. I am sorry thus to trespass on your space, but being anxious, as MR. WILKINSON says, to collect information from every source, and your periodical being a happy medium for conveying and receiving instruction, I am glad to avail myself of such a channel. [Phi]. (2) P.S.--Mr. Claudet has, I perceive, been awarded the prize given by the Society of Arts for the best essay on the stereoscope. Can you, or any of your readers, inform me whether this is likely to be published, and when and at what price? _Query respecting Mr. Pollock's Process._--In MR. POLLOCK's directions for obtaining positives which appeared in "N. & Q." (Vol. vii, p. 581.), iodide of silver is to be dissolved in a saturated solution of hypo. Can you give me the quantity of iodide of silver to be dissolved, and the quantity of the saturated solution of hypo. in which it is to be dissolved? N. T. B. _Gallo-nitrate of Silver._--Can you inform me what the true nature of the decomposition is which takes place after a short time in the gallo-nitrate solution of silver? and if there be any ready means of rendering the silver it contains again available for photographic use? SIR W. NEWTON, in the description of his calotype process, says: "Bring out with the saturated solution of gallic acid, and when the subject begins to appear, add the aceto-nitrate of silver solution." Which way of doing this is the best,--mixing the two solutions together and applying them to the paper; or applying the paper, when wetted with the gallic acid, to the silver solution? T. L. * * * * * Replies to Minor Queries. _Verney Note decyphered_ (Vol. vii., p. 568.).--I am extremely obliged to MR. THOMPSON COOPER for his decyphered rendering of Sir Ralph Verney's note of a speech or proceeding in parliament. The note itself is not now in my possession, but I have requested the owner to be good enough to re-collate it with the original, and if any mistakes should appear in the copy, or the printing (which is very likely), I will give you notice of the fact, that the doubtful words in MR. COOPER's version may, if possible, be set right. Students in the art of decyphering may be pleased to have the key to the cypher recorded in {18} your pages. I therefore give it you as discovered by MR. COOPER, and beg, in the strongest way, to reiterate my thanks to that gentleman. 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, f, r, k, t, b, h, s, w, c, g, p, d, a, e, i, o, u, 20, 22, 27, 28. l, x, m, n. The cyphers (if any) for _j, q, y, z_ have not been discovered, and the numbers 1, 19, 21, 23, 24, 25, 26 remain unappropriated. JOHN BRUCE.