I hurried to write a sheet of note music at once to print it in the new way; but the ink flowed too much on the polished stone. Previously I had corrected this by rubbing the stone with linseed oil or soap-water, which checked the trouble entirely. But I knew that I could not do that in this new method, because then the stone would have a coating of grease all over, and would take color on the entire surface. However, I was able to take this coating away after writing, by etching with aqua fortis, though etching would not have been necessary otherwise in this chemical form of printing. However, it was easy to see that a drawing etched into relief would be easier to print from than one not etched at all. It did not require much etching, and I saved a great deal of acid, while the stone, also, remained useful for new work for a much longer period. Therefore, without making further experiments, I adhered to my old method, first washing the stone lightly with soap-water, drying it well, writing on it with wax ink, and then etching with acid before I finished it for printing by pouring gum solution over it. At first I imagined that I might do without the gum entirely; but I found soon that it really formed a sort of chemical union with the stone, making its pores more receptive to the grease and closing them more effectively against water. I found also that neither aqua fortis nor gum was so valuable alone as when both were used in the process. I needed to make only a few more experiments to obtain the proper consistency of ink, and the new process would be practically perfect so far as the fundamental principle was concerned. And, in fact, I made such handsome, clean, and strong impressions after three days of trial that few better ones have been made since. Now it was necessary merely to train skillful workmen and artists as quickly as possible for this new art, that was susceptible of innumerable valuable uses, as I could see at once. It made no difference now whether the design was worked in relief or intaglio, as good impressions could be obtained even when the drawing was perfectly level with the surface of the stone. But all three methods could be combined on one stone, if desired. If I reversed the method, by rubbing oil over the stone instead of water, while for printing I used an ink prepared with gum solution (of which I will describe the best composition afterward), then the greasy places would resist color while the wet ones took it, and thus I could print with all water colors, and this is necessary sometimes with colored pictures because of the greater height of the colors. The inscription with dry soap gave me the logical idea toward crayon work, which I used afterward. My previous experiments with etching, that recurred to my memory, now assumed entirely different aspects and I could understand many things that had puzzled me then.