After the picture had been obtained on the plate (ordinary glass plate), and after thoroughly fixing, washing, and toning, the picture (and this, remember, is the case likewise with terra-cotta) then has to be loosened from its support, and this is done with a solution of sulphuric acid--one drachm to fifteen ounces of water--which is made to flow between the image and the glass, after which perfectly wash and mount. When the image is loosened a piece of tracing paper is put on the image, evened out, raised (assisted by some one else to hold the two opposite corners during the operation), and with the aid of the helper the picture is carefully centered, gently pressed out or down, and the transfer is so far effected. But what will happen, and does happen, in the case of vignettes, is impurity of the whites, when the picture becomes positively objectionable. Now the way to remedy this lies simply in the application, to the dirty-looking parts, of a solution of iodine dissolved in iodide of potassium to sherry color; after which, well wash and apply a weak solution of cyanide of potassium, and wash well again. This, by the way, is equally applicable to paper transfers; and it is to be remembered that the toning comes last of all. It is a rather difficult matter to clean a ground opal which has been used two or three times, and acid must then be had recourse to (nitric acid is as good as any); but by transferring from the support on the ground surface, all stains are at once avoided. On the flushed glass, or on the pot metal (unground), after well cleaning the surface it should be covered with a substratum of egg. Then the picture is taken direct, not transferred; that is, the plate is exposed direct in the camera, regularly proceeded with, and, when dried, varnished with a pale negative varnish, or with dead varnish if intended for chalk or water-color. This, when a good negative is used, gives a remarkably fine picture, not requiring a vestige of retouching, and having likewise the invaluable advantage of being perfectly durable if varnished with the negative varnish. Moreover, on that, effective pictures may be made in oil with simply tinting. A gentleman, who has a right to be considered a good judge in all art matters, on looking at one of these pictures transferred on flushed glass, said it was one of the finest productions of photography. He urged that negatives _ad rem_ should be taken most carefully, and that, like the picture I showed him, they should be full of half-tone and detail, and yet have plenty of vigor. They should, he said, be robust in the high lights, have perfectly clear glass in the few points of deep shadows, and thus have powerful relief. Moreover, the negatives should be retouched only by a competent hand, and care taken that the likeness shall be in no way altered, which is so frequently the case now.