Martyn's Plantæ Cantabrigienses. 12mo. London, 1763.
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Notices to Correspondents.
Owing to a necessity for going to press this week at an unusually early period, that the present Number might be included in the Monthly Part, we are compelled to omit replies to many Correspondents.
L. A. M. (Great Yarmouth) will find several Notes respecting the means of discovering the bodies of the drowned in our 4th Vol., pp. 148. 251. 297.
H. O. N. (Brighton). In our own practice we have never obtained pictures with the agreeable colour which is produced by the iodide of silver, when iodide of ammonium has been used. The flaking of the collodion would indicate an excess of iodide, and is often cured by the addition of about twenty drops of alcohol to an ounce of collodion. The feathery appearance is difficult to comprehend, without seeing a specimen. If you are using glass which has been previously used, the most minute remains of iron would cause a discoloration. Muriatic acid is the most effectual remedy for cleaning glass so used. It may be procured at 2½d. per lb., and should be diluted with three parts of water.
An Amateur (Oxford). We are not of opinion that Mr. Talbot could restrain any one from taking collodion portraits, as patentee of the Talbotype process. It is done in many parts of London daily without any permission.—See Times' Advertisements, &c.
C. E. F. We think you use too strong a solution of the ammonio-nitrate of silver: thirty grains to the ounce of water, and then redissolved with the strong liq. ammon., give to us most satisfactory result,—the paper being prepared before with chloride of barium, chloride of sodium, and chloride of ammonia, of each half a drachm to the quart of water, in which half an ounce of mannite, or sugar of milk, has been previously dissolved. When sufficiently printed, put it into the hypo. sulph. solution, without previous immersion.