and when dry placed it in the camera. In about forty-five minutes I
plainly percieved 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, &c. 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 sal.
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."

I have very recently learned, that, under the present patent laws
of the United States, every foreign patentee is required to put
his invention, or discovery, into practical use within eighteen
months after taking out his papers, or otherwise 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 art if they feel disposed.
From the statement of Mr. Wattles, it will be perceived that this
can be done without dishonor, as in the first instance Mr. Talbot
had no positive right to his patent.