M. Niepcé de St. Victor finds that, if a sheet of paper on which there

is writing, printed characters, or a drawing, be exposed for a few
minutes to the vapour of iodine, and there be applied immediately
afterwards a coating of starch, moistened by slightly acidulated
water, a faithful tracing of the writing, printing, or drawing, will
be obtained. M. Niepcé has also discovered that a great number of
substances, such as nitric acid, chlorurets of lime and mercury, act
in a similar manner; and that various vapours, particularly those of
ammonia, have the effect of vivifying the images which are obtained by
photography.

In the words of a writer in the _North British Review_:--“While
the artist is thus supplied with every material for his creative
genius, the public will derive a new and immediate advantage from the
productions of the solar pencil. The home-faring man--whom fate or
duty chains to his birth-place, or imprisons in his fatherland--will,
without the fatigues and dangers of travel, scan the beauties and
wonders of the globe; not in the fantastic or deceitful images of a
hurried pencil, but, in the very picture which would have been painted
on his own retina, were he magically transported to the scene. The
gigantic outline of the Himalaya and the Andes will stand self-depicted
upon his borrowed retina--the Niagara will pour out before him, in
panoramic grandeur, her mighty cataract of waters, while the flaming
volcano will toss into the air her clouds of dust and her blazing
fragments. The scene will change, and there will rise before him
Egypt’s colossal pyramids, the temples of Greece and Rome, and the
gilded mosques and towering minarets of eastern magnificence. But
with not less wonder, and with a more eager and affectionate gaze,
will he survey those hallowed scenes which faith has consecrated and
love endeared. Painted in its cheerless tints, Mount Zion will stand
before him, ‘as a field that is ploughed;’ Tyre, as a rock on which
the fishermen dry their nets; Gaza, in her prophetic ‘baldness;’
Lebanon, with her cedars prostrate among ‘the howling firs;’ Nineveh
made as a grave, ‘and seen only in the turf that covers it;’ and
Babylon the great, the golden city, with its impregnable walls, its
hundred gates of brass, now ‘sitting in the dust, cast up as an heap,’
covered with ‘pools of water,’ and without even the ‘Arab’s tent,’ or
the ‘shepherd’s fold.’ But though it is only Palestine in desolation
that a modern sun can delineate, yet the seas which bore on their
breast the Divine Redeemer, and the everlasting hills which bounded
his view, stand unchanged by time and the elements, and, delineated
on the faithful tablet, still appeal to us with an immortal interest.
But the scenes which are thus presented to us by the photographer have
not merely the interest of being truthful representations: they form,
as it were, a record of every visible event that takes place while the
picture is delineating. The dial-plate of the clock tells the hour and
minute when it was drawn, and with the day of the month, which we know,
and the sun’s altitude, which the shadows on the picture often supply,
we may find the very latitude of the place which is represented. All
stationary life stands self-delineated on the photograph:--the wind, if
it blows, will exhibit its disturbing influence; the rain, if it falls,
will glisten on the house-top; the still clouds will exhibit their
ever-changing forms; and even the lightning’s flash will imprint its
fire-streak on the sensitive tablet.”