In about forty-five minutes I plainly perceived the effect, in the gradual darkening of various parts of the view, which was the old stone fort in the rear of the school garden, with the trees, fence, etc. I then became convinced of the practicability of producing beautiful solar pictures in this way; but, alas! my picture vanished and with it, all -- no, not all -- my hopes. With renewed determination I began again by studying the nature of the preparation, and came to the conclusion, that if I could destroy the part not acted upon by the light without injuring that which was so acted upon, I could save my pictures. I then made a strong solution of soda I had in the house and soaked my paper in it, and then washed it off in hot water, which perfectly fixed the view upon the paper. This paper was very poor with thick spots, more absorbent than other parts, and consequently made dark shades in the picture where they should not have been; but it was enough to convince me that I had succeeded, and that at some future time, when I had the means and a more extensive knowledge of chemistry, I could apply myself to it again. I have done so since, at various times, with perfect success; but in every instance laboring under adverse circumstances."
Under the patent laws of the United States at the time this was written, every foreign patentee is required to put his invention, or discovery, into practical use within eighteen months after taking out his papers; otherwise he must forfeit his patent. With regard to Mr. Talbot's calotype patent, this time has nearly, if not quite expired, and my countrymen are now at perfect liberty to appropriate the artistic method if they feel disposed. From Mr. Wattles' statement above, this can clearly be done without dishonor; Mr. @Talbot, for all his claims, had no positive right to his patent in the first place.
