for producing chlorine gas (in small quantity) in the retort.
The result was that my first experiment produced an impression
completely solarized in all its parts by an exposure of four seconds
of time, which would have required an exposure of twenty seconds
to produce a perfectly developed impression by the usual process.

Another trial immediately produced one of the finest toned impressions
I ever saw, perfectly developed in one second of time.

My next two or three experiments proved total failures.
I was unable to produce even a sign of an impression.
By accident my retort was broken, and not being in a
locality convenient to obtain another, my experiments
were necessarily suspended.

My attention was not called to this subject again for several years,
when I noticed an account of some similar experiments by F. A. P. Barnard
and Dr. W. H. Harrington, the latter of whom is now of the firm of Dobyns
& Harrington, of New Orleans.

From reading this article, I found my own difficulties explained.
Too much of the chlorine gas was present in my coating jar.
I would like to see some of our enterprising operators
investigate this combination.

It is a singular fact, that the vapors of bromine and chlorine combining
upon the iodide of silver, produce a more sensitive coating than when
the two are combined in solution, as in chloride of bromine solution.
Those having Humphrey's Journal at hand, can refer to vol. i. p. 142.