I now planned to do this with the book. But why could I not invent an ink that would serve on the stone without making it necessary to trace over it with the stone-ink? Why not make an ink that would leave the paper under pressure and transfer itself to the stone entirely? Could one give the paper itself some property so that it would let go of the ink under given conditions? So reflected I, and it seemed to me not impossible. At once I began to experiment. I had observed that the stone-ink at once began to congeal and stiffen when it came into contact with ordinary writing-ink, because of the action of the vitriol of iron, which devoured the alkali that the stone-ink needed to keep it in solution. Therefore I wrote with ordinary ink, into which I put still more vitriol of iron. After it was dry, I dipped the sheet into a weak solution in water of my stone-ink. After a few seconds I withdrew it and washed it very gently in rainwater. I found that the ink had fastened itself on the written places, and pretty thickly, too. I allowed the paper to dry slightly and transferred the writing to the stone. The impression was fair, but not sufficiently complete. I tried it repeatedly but could obtain no transfers that were sharp and uniform enough to represent a handsome script. So I tried another way. I painted the paper with gum solution in which vitriol of iron was dissolved. After it dried I wrote on it with my ordinary stone-ink and dried it again. Then I dampened the paper and let it lie a while to soften, after which I transferred it to the stone, which had been treated with strong oil varnish diluted in oil of turpentine, laid on so lightly that it was only like the blurring from a breath. These attempts were far more successful, but it was impossible to write as delicately on this paper as I desired. Therefore I made new experiments. I changed the mixture of my ink. I tried to make it more adhesive with mixtures of resin, oil varnish, gum elastic, turpentine, mastic, and similar substances. In short, I do not exaggerate when I declare that this matter cost me several thousands of experiments. I was rewarded sufficiently by succeeding. And at the same time through these investigations I discovered the chemical printing on stone of to-day.