Thos. L. Mansell.
The Double Iodide Solution—Purity of Photographic Chemicals.—The observations of Mr. Leachman upon the solvent powers of iodide of potassium (Vol ix., p. 182.) are perfectly correct, but I believe our photographic chemicals are often much adulterated. The iodide of potassium is frequently mixed with the carbonate. Dr. Mansell writes me word, in a comment upon your note upon his communication, "What I used was very pure, having been prepared by Mr. Arnold with great care: it was some that had gone to the Great Exhibition as a sample of Guernsey make, and obtained a medal." I have this day used exactly seven ounces avoirdupois to make a pint of the iodizing solution, which, within a few grains, agrees with my former results. Nitrate of silver, I am informed upon a most respectable authority, has been adulterated thirty per cent., and without careful testing has eluded detection; but I am inclined to think our cheapest article has come in for its largest share of mixture. I have lately perfectly failed in the removal of the iodide of silver with a saturated solution of what I purchased as hyposulphite of soda, but which could have been little else than common Glauber's salts; for upon applying a similar solution of some which was made by M. Butka of Prague, and supplied me by Messrs. Simpson and Maule, the effect was almost immediate, demonstrating how much we are misled in our conclusions, from believing we are manipulating with the same substances, when in fact they are quite different.
Hugh W. Diamond.
Hyposulphite of Soda Baths.—Is there any objection to using the same bath (saturated solution of hyposulphite) for fixing both paper calotype negatives and positives printed on albumenized paper from glass collodion negatives?
C. E. F.
Replies to Minor Queries.
Daughters taking their Mothers' Names (Vol. viii., p.586.).—Buriensis asked for instances of temp. Edw. I., II., III., of a daughter adding to her own name that of her mother: as Alice, daughter of Ada, &c. Though I am not able to furnish an instance of a daughter doing so, I can refer him to a few of sons using that form of surname some years earlier, but the practice seems very limited. Thus in Liber de Antiquis Legibus, published by the Camden Society, we have, among the early sheriffs of London in 1193, Willielmus filius Ysabelis, or, as in the appendix 222, Ysabel; in 1200, Willielmus filius Alicie; in 1213, Martinus filius Alicie; and in 1233 and 1246, Simon filius Marie,—the same person that, as Simon Fitz-Mary, is known as the founder of the Hospital of St. Mary Bethlehem Without, Bishopsgate.
W. S. W.
Middle Temple.