Rev. E. B. (B***) is requested to state the subject of his communication. In his last very extraordinary letter he has omitted this important piece of information.
C. E. F. who complains of the disappearance of a portion of the collodion film at the spot where the hyposulphite of soda is applied, is informed that this is by no means an uncommon occurrence, and indicates the feeble action of the light at the present time of year. By using the glass a little larger than is required, as has been before recommended, and pouring the hyposulphite of soda on the portion which is to be cut off, and allowing it to flow over the picture, the defect will generally be avoided. A much stronger solution of the hyposulphite of soda may be used—say, one ounce to two ounces of water; and then, by preserving the solution, and using it over and over again, a more agreeable picture is produced. The solution, when it becomes weak, may be refreshed by a few crystals of the fresh salt added to it.
F. W. If the bath of nitrate of silver produces the semi-opaque appearance upon the collodion, in all probability there is no hyposulphite of soda in the bath: three or four drops of tincture of iodine added to each ounce of the solution of nitrate of silver in the bath, often acts very beneficially. All doubtful solutions of nitrate of silver it is well to precipitate by means of common salt, collect the chloride, and reduce it again to its metallic state. The paper process described by Dr. Diamond in our 166th Number is calculated both for positives and negatives.
"Notes and Queries" is published at noon on Friday, so that the Country Booksellers may receive Copies in that night's parcel, and deliver them to their Subscribers on the Saturday.
THE ECLECTIC REVIEW for JANUARY, price 1s. 6d., or by post 2s. (commencing a new volume), contains:
VIII. The Hungarian Struggle and Arthur Görgey.
VIII. Scottish Preachers and Preaching.
VIII. Thackeray's History of Colonel Esmond.
IIIV. British South Africa.