The Sun.
London, England, 1839-08-26 00:00:00

THE. DAGUERREOTYPE•

It having been announced that the process em-
ployed by M. Daguerre, for fixing images of objects
by the camera obscura, would be revealed on Mon-
day at the sitting of the Academy of Sciences,
every part of the space reserved for visitors was
filled as early as one o'clock, although it was known
that the description of the process would not take
place until three. Upwards of two hundred per-
sons, who could not obtain admittance, remained
in the court-yard of the Palace of the Institute.
The following is an analysis of the description
given on this occasion by M. Arago :
The influence of light upon colours was known
long ago. It had been observed that substances
exposed to its action were affected by it; but
beyond this fact, nothing was known until
1566, when a peculiar ore of silver was dis-
covered, to which was given the name of argent
corne, and which had. the property of becoming
black when exposed to the light. Photographic
science remained at this point until it was disco-
vered that this argent corn, (chloruret of silver)
did not become black under all the rays of light. it
was remarked that the red ray scarcely effected any
change, whilst the violet ray was that which pro-
duced the greatest influence. M. J. Baptiste Porta
then invented the camera obscura, and numerous
NlieedP to o ' the
which
p
efforts were made to fix the pretty miniature objects
which were seen upon the table of it, and the
transitory appearance of which was a subject of
general regret. All these efforts were fruitless up
tor
et
ched
ed
the time
that
ao
tf
ot
fh emi n. ve nti on of M
Daguerre,
and
ex-
traordinary result that the latter gentleman has ob-
tained. M. Niepce, after a host of attempts, em-
ployed sheets of silver, which he covered with
bitumen (Minnie de Judee) dissolved in
oil of lavender, the whole being covered
with a varnish. On heating these sheets
the oil disappeared, and there remained a
whitish powder adhering to the sheet. This sheet
tocoenew meansd
from the Fo tv
thus prepared, was placed in the camera
rthis
purpose obscura,
but when withdrawn the objects were hardly visible
for rendering
rnei it.l dher e
i nAgI p .ut
thehois sheets,Niepcebjeett hs en
more
resortedwrleiet distinct.
i removed
min
camera obscura, into a mixture of oil of lavender and
oil of petroleum. How M. Niepce arrived at this
wash
discovery was not explained to us ; it is sufficient to
state that, after this operation, the objects became
aosnlyvisirbelmeaiansedthtoo the sheet those
of ordinary ngtra vings, and it
with distilled
water to make the drawings permanent. But as
the hitunie de Judee is rather ash-coloured than
employed
means of
redtidofnot succeed
white, M. Niepce had to discover the
blacken-
potassium
iiinigcretahseinglintelsieoshacandziowre•ss)b.y more
For
thisde e p l y
Niepce)sulphu purpose he
iodin
ea. newßut mixturehe( of.
as he expected to do, for the iodine spread itself
over the whole surface, and rendered the objects
more confused. The great inconvenience, however,
of the process was the little sensitiveness of the
coating (enduit), for it sometimes required three
days for the light to produce sufficient effect. It
will easily be conceived, therefore, that this means