Year: 1868




passes will be given these people toyisit
headquarters for the purpose Of making


personal application for trade permits


Maj.-Gen. GRANT.
Dangers In the Use of Photo
graphic Chemicals.


NJ. Davanue lately read a paper on


this subject before the French Photo
graphic Society, Paris An unfortunate
photographer had been endeayoring to
prepare some chloride of gold and potas-
sium, but making some error in mixing
OF making his solutions, he spoiled them


Upon consulting some one as to how be
could get back his gold, he was advised
to add ammonia to the solution, instead
of the more wise plan of using sslphate
of iron, formic acid, or sulphate Of soda,
etc. Chemical readers would not have
added the ammonia, knowing that the
dangerous compound known as fulmi-
mating gold would be produced but all
/ photographers are not chemists, though
they should be. The poor man added
ammonia, and made the explosive COM
pound in considerable quantities 1t
naturally exploded, and, sad to relate,
destroyed one eye completely and in
iured the sight of the other very seri-
ously, beside other damage.


Among other dangers to which photo
graphers are exposed, IS that which
arises from the heavy character Of the
vapor of ether. Although all light may
be long distance away from the bottle
from which the ether is being poured,
vet the heavy vapor rolls down and over
/ the receiving vessel, and finds its way to
the ground like 4 stream of water and
if there be an open fireplace or furnace
near, the draft from it will draw on the
stream of ether vapor, and igniting, the
/ fame will run along to the bottle as if
along a train Of gunpowder, and set fire
to the ether in the hands of the opera
tor, probably killing him by burning.
Then the mixture of alcohol and ether
vapors with atmospheric air forms mix
ture as explosive as fire damp, and cir
cumstances may arise in Photographic
manipulations when this dangerous mix
ture may be produced.


NJ. Davanne, who is a professor Of
chemistry, now proceeded to practical
demonstration of some of the properties
of the dangerous substances that photo
graphers might produce in their opera
tions. He had prepared at home some
of these, but, as he said, in very minute
quantities for, irrespeetively of the
! danger to himself in making them, and
the risk of injury to his audience in
exhibiting them, there was the chance
of doing some damage and creating a
disturbance on the Boulevards as he
came with them to the meeting. He
took solution of chloride of gold and
added ammonia to it, and showed the
precipitate of Illuminating gold, which
had done so much injury to his CORES
pondent, and taking a minute quantity
of it, which he had previously dried, he
caused it to explode by merely touching
it on glass plate with a glass rod. A
piece Of fltering paper, on which was a
minute portion, was held over the fame
of spirit lamp and exploded immedi-
ately /; and a capsule in which was lit
tie was shattered to atoms and scattered
over the room.


NJ Davanne then called attention to
similar compound of silver, which might
be easily produced by an unwary photo
grapher. especially that solutions of OK
ide Of silver in ammonia are now so fre-
quently recommended for Photographic
purposes a solution Of nitrate of sill
yer in ammonia is harmless a.. a solu-
ton of oxide Of silver and nj
trate Of ammonia, with excess of ammo
MAJ but if the oxide be precipitated
from this solution by caustic potash,
compound is produced of even greater
explosive properties than Illuminating
gold, viz Illuminating silver. This dan
gerous compound, not content with go
ing off - when dry, is so unstable that it
will detonate under water.


Then, photographers with a smatter-
ing of chemistry may know that iodine
and iron combine and make iodide Of
iron without danger, and, by a wrong
process of reasoning, may conclude that
iodine and ammonia may combine quiet
ly and produce the iodide ammonium for
their collodion. Nothing is more falIa-
cious, and now that the ammonio-iodides
are again before the Photographic pub
lie, manipulatOrs who prepare their
own chemicals " will do we'll to be eau
tious in mixing iodine and ammonia
This mixture, unless accomplished as re-
commended by the Rev J. B. Reade
many years ago, will produce an iodide |
of nitrogen in the form of brown pow
der, which is so explosive that if only !
touched with feather when dry, will |
Immediately explode.


Another frighful compound of nitro
gen is produced whenever nitrogen is
passed through solution of sal ammo
MIA Chloride of ammonium) and al
though at present photographers are not
likely to have anything to do with this
fearful compound, NJ Davanne wished I
to point out Its properties. 1t is an oily /
liquid, and explodes almost without ac-
tual touch, smashing lead dishes in which
it may be placed and carrying destruc-
ton all around. The discoverer was
manned twice with it, other experiment.
ers have not Jared much better, and M.
Davanne confessed he had never seen
the compound, and never wished to do
so.


But there is still another compound of
silver which is dangerous, and which a
photographer might unwittingly pro-
duce-the illuminate of silver. If So
luton Of nitrate of silver containing nj
tric acid be warmed, and alcohol added.
a white precipitate forms, which is the
compound in question, and which is very
dangerous, as viii be conceived when we
remember it is that compound to which
percussion owe their good qualities. and
which, when carelessly handled. not un
frequently will blow up a whole factory.
machinery and all. A photographer
evaporating to dryness an acid bath
which had been in use long, and CON
tanned alcohol, might find himself and
his dishes elsewhere toward the termi-
nation of the boiling down Of the solu,
ton,