_Towgood's Paper._--A. B. (Vol. ix., p. 83.) can purchase Towgood's paper of Mr. Sandford, who frequently advertises in "N. & Q." With regard to his other Query, I think there can be no doubt of his being at liberty to publish a photographic _copy_ of a portrait, Mr. Fox Talbot having reserved only the right to paper copies of a _photographic_ portrait. Collodion portraits are _not_ patent, but the _paper_ proofs from collodion negatives are. GEO. SHADBOLT. {111} _Adulteration of Nitrate of Silver._--Will any of your chemical readers tell me how I am to know if nitrate of silver is pure, and how to detect the adulteration? _If so_ with nitrate of potash, how? One writer on photography recommends the fused, as then the excess of nitric acid is got rid of. Another says the fused nitrate is nearly always adulterated. I fear you have more querists than respondents. I have looked carefully for a reply to some former Queries respecting MR. CROOKES's restoration of old collodion, but at present they have failed in appearance. THE READER OF PHOTOGRAPHIC WORKS. * * * * * Replies to Minor Queries. _Passage of Cicero_ (Vol. viii., p. 640.).--Is the following what SEMI-TONE wants? "Mira est enim quædam natura vocis; cujus quidem, _e tribus omnino sonis_, inflexo, acuto, gravi, tanta sit, et tam suavis varietas perfecta in cantibus."--_Orator_, cap. 17. B. H. C. _Major André_ (Vol. viii., pp. 174. 604.).--The late Mrs. Mills of Norwich (_née_ André) was not the sister of Major André; she was the only daughter of Mr. John André of Offenbach, near Frankfort on the Maine, in Germany; where he established more than eighty years ago a prosperous concern as a printer of music, and was moreover an eminent composer: this establishment is now in the hands of his grandson. Mr. John André was not the brother of the Major, but a second or third cousin. Mrs. Mills used to say, that she remembered seeing the Major at her father's house as a visitor, when she was a very small child. He began his career in London in the commercial line; and, after he entered the army, was sent by the English ministry to Hesse-Cassel to conduct to America a corps of Hessian hirelings to dragoon the revolted Americans into obedience: it was on this occasion that he paid the above-mentioned visit to Offenbach. Having frequently read the portion of English history containing the narrative of the transactions in which Major André was so actively engaged, and for which he suffered, I have often asked myself whether he was altogether blameless in that questionable affair. TRIVET ALLCOCK. Norwich. P.S.--This account was furnished to me by Mr. E. Mills, husband of the late Mrs. Mills.