Further, I may enlighten MR. SHADBOLT by assuring him that the iodizing paper with the ammonio-nitrate of silver, which I never saw published yet, is the best way; and I may confidently assert that the better ways of iodizing papers are not published at all. It is a tedious process to do, but it is as certain as taking a positive from a negative. At present I have not space to give my way of doing it. I may also add, that it will not answer with all papers. In fact, all samples of paper require some modification of the process, as the chemicals are different in the various modes of bleaching paper by different manufacturers. The ammonio-nitrate is perfect with Whatman's paper; indeed it is a subject of much regret, that this maker has not turned out a paper as thin and hard as the Canson Frères. The latter gentlemen have added some chemical, probably iodine, to their paper, which renders it almost impossible to iodize it at all. I believe it to be iodine, because the paper becomes perfectly black over _free_ iodine, which no English paper will do. At all events, this paper is very uncertain, although it has a quality in appearance that is unsurpassed by any other. WELD TAYLOR. 7. Conduit Street West, Bayswater. _Sir William Newton's Process: Further Explanations._--In reply to your correspondent F. MAXWELL LYTE, who is desirous of knowing my motive for washing the paper over with chloride of barium previous to iodizing-- In the first place, I find that it appears to give strength to the paper. Secondly, that the action in the camera is better and more certain. Thirdly, it keeps cleaner in the bringing-out process, thereby allowing a longer time for a more complete development. Fourthly, I have never found any _solarizing_ take place since I have used it (about three years); and, fifthly, I find that it keeps longer and better after it is excited for the camera. From the observations which I have made since I have made use of chloride of barium, I conclude that it has the effect of _destroying_ any injurious properties which may be in the paper, and more especially with respect to the SIZE; and besides which, when combined with iodide of silver, greater intensity is obtained in the negative. I have occasionally prepared paper without chloride of barium, but I have always found (except for positives) that I could not rely upon it with the same degree of certainty. I need scarcely add that throughout the whole of this process the greatest care and attention is required, and that the water should be constantly agitated while the paper is in it, and that the water should be once changed. W. J. NEWTON. 6. Argyle Street. * * * * * Replies to Minor Queries.