injured in effect from this rouge tint disseminated throughout
their shaded features, at the same time that the whole
general effect of such pictures is that of a want of life.
It is true that with the use of rouge a very high degree of polish
may be obtained, but probably not higher than can be produced
with many other substances of a less objectionable nature.
From the announcement of the discovery by Daguerre to the beginning
of the year 1840, I am not aware of any attempt to lessen the time for
the action of an image, or an impression, other than that of the reflecting
camera invented by Mr. Wolcott. Early, however, in 1840, Mr. Wolcott
was desirous to be enabled to further shorten the time for a sitting,
and having some knowledge of bromine and its action, by request,
Dr. Chilton prepared a small quantity; but Mr. Wolcott did not succeed
very well with it, he having invariably used too much in combination with
iodine to produce that sensitive coating now well known to the profession.
Professor Morse, of this city, Dr. Goddard, of Philadelphia, and others,
in the years 1840 and 1841, were acquainted with the use of bromine.
N. Griffing, of this city, or myself, used with tolerable success,
iodine in large excess to nitric acid and water; and, subsequently, to nitro
muriatic acid (which reacted and formed a peculiar chloride of iodine);
this latter combination proved to be preferable to simple iodine,
at the same time somewhat more sensitive, and was used by me in this city up
to the time of my leaving for London (October 1, 1840). On arriving in London,
I instituted a series of experiments in the various chemical combinations,
solely with the view to be enabled to obtain more speedily a portrait
than it was practicable to do with any known chemicals at that date.
The high latitude, and the winter season of the year rendering but a
feeble light at best, the greater the necessity for a more sensitive
chemical preparation to the shortening the time for a sitting.
Near the beginning of the year 1841, I discovered and practically applied,
chloride of iodine to great advantage, and, as far as memory serves me,
I believe the first used in this country was some made and shipped, Messrs.
Harnden & Co., from London, to Mr. Wolcott, in New York.
About the same time, Mr. John Goddard, of London (who was associated
with myself), discovered a rather valuable combination of chemicals,
consisting of a mixture of iodine, bromine, iodus, and iodic acid,
and a proper combination of those bodies gave an action somewhat
more sensitive than chloride of iodine--but the "high lights"
of the portraits would become solarized or overdone, more frequently
with this combination than with the chloride of iodine.
Throughout the year 1841, I used, with great success, chloride of iodine,
applied as one coating--occasionally in conjunction with Mr. Wolcott,
attempting the use of iodine, bromine, and chlorine, and at times
with more or less success. The difficulty of exactly combining,
the three elements above mentioned, in order to produce a certainty
of result with harmony of effect, was the work of many months,
with great labor and study, the slightest modification requiring
a long, series of practical experiments, a single change consuming,
frequently, an entire day in instituting comparisons, etc., etc.
Early in the year, 1842, I discovered a combination of chemicals
(now known in London as "Wolcott's Mixture," in hermetically sealed bulbs)
of exceeding uniform character, very sensitive to the action of light,
and specimens produced in 1842-3, with this combination, will bear
comparison with the best specimens produced at this late date.
About the same time, I discovered that however much overdone a