having been washed in the hyposulphate of soda, and afterwards in
distilled water.
_First process for biting in or engraving the plate._--The following
solutions must be put in the capsulæ, in sufficient quantity, so as to
entirely cover the plate:--1. Acidulated water. 2. Alkaline water. 3.
Alcoholized potash, in covered capsulæ. 4. Caustic potash, in covered
capsulæ. 5. Distilled water.
The plate being then put upon the glass holder or spoon, is plunged in
the acidulated water, and agitated during a few seconds, then put into a
glass funnel, and washed with distilled water. It is taken again with the
glass spoon, and plunged in the capsulæ containing alcoholized potash.
This capsulæ is covered with its glass cover, and then heated, by means
of a spirit lamp, to about 140° Fahrenheit. The plate must remain in the
capsulæ half an hour, during which the solution is heated now and then,
and agitated. During that time the following acid solution, which will be
called _nomal acid_, must be prepared: it is composed as follows:--Water
600 parts, nitric acid 45 parts, solution of nitrate of potassa 12 parts,
solution of common salt 45 parts. These proportions are in volume. The
nomal acid must be poured in a capsulæ, covered with its glass cover, and
a sufficient quantity must be kept in the bottle.
When the plate has been immersed in the alcoholized potash during half an
hour, it is taken out of the solution by means of the glass holder, and
immediately plunged in the alkaline water, and agitated pretty strongly;
from thence it is put in distilled water (A). This being done, the plate
is plunged in the acidulated water, and moved about therein for a few
seconds: it is then put into the nomal acid. When the plate has been
immersed a few seconds in the acid, it is taken out by means of the glass
holder, taking care to keep it as much as possible covered with the
solution, and it is immediately placed horizontally upon a stand, and as
much acid as the plate can hold is poured upon it from the bottle; it is
then heated with a spirit lamp, but without attaining the boiling point.
During this operation it is better to stir or move about the acid on the
plate by pumping it, and ejecting it again, by means of a pipette or glass
syringe; after two or three minutes the acid is thrown away, the plate is
put in the glass funnel, and then well washed with water, and afterwards
with distilled water (B).
Thus, without letting the plate dry, it is put upon the fingers of the
left hand, and with the right hand some ammoniacal chloride of silver,
which is moved about the surface by balancing the hand is poured upon it;
the solution is renewed until the chloride, formed by the action of acid,
is dissolved; the plate is then washed by pouring upon it a large quantity
of ammoniacal water, and afterwards some distilled water. (C.)
Without allowing the plate to dry, it is then put in the caustic potash,
and the capsula being then placed upon the stand, the potash is heated up
to the boiling point; it is then left to cool (D); and beginning again the
operations described from A, to D, a second biting is obtained; and by
repeating again the operations described in A, and B, a third biting is
produced. The plate is then dried; in this state the black parts of the
plate are filled with chloride of silver.
The plate is then polished until the white parts are perfectly pure and
bright. This polishing is soon done with cotton and ('ponce') (pumice
stone); afterwards, the chloride of silver, filling the black parts, is
cleansed by the means described in B, and C. The plate is dried, but
before drying, it is well to rub the plate slightly with the finger, in
order to take off from the black parts any remains of an insoluble body,
which generally remains on it. The preparatory engraving is then finished,
and the plate has the appearance of a very delicate acquatint engraved
plate, not very deeply bitten in.
Nevertheless, if the operation has been well managed, and has been
successful, it is deep enough to allow the printing of a considerable
number of copies.
_Note._--Sometimes, instead of treating the plate with the boiling potash
in the capsula, a similar result may be obtained by placing the plate
upon the stand, covering it with the solution, and heating it by means
of a spirit lamp, until, by evaporation the potash becomes in a state of
ignited fusion. By this means the grain is finer, but the white parts are
more liable to be attacked.
Last operation of biting in: This operation requires some of the
re-agents, before-named, and also,
1. A siccative ink, made of linseed oil, rendered very siccative by
boiling it sufficiently with litharge; it may be thickened with calcined
lampblack.
2. An electrotype apparatus, and some solutions of it to gild, and copper
the plate.
Means of operating: The plate must be inked as copper-plate printers do,
taking care to clean off the white parts more perfectly than usual; the
plate is then to be placed in a room sufficiently warm, until the ink is
well dried, which requires more or less time, according to the nature of
the oil employed. The drying of the oil may be hastened by heating the
plate upon the stand with the lamp, but the slow process is more perfect
and certain.
When the ink is well dried, the white parts are cleaned again, by
polishing the plate with cotton and ponce, or any other polishing powder;
a ball of cotton, or any other matter covered over with a thin piece of
caoutchouc or skin, can be used for this purpose. When polished the plate
is ready to receive the electro-chemical coating of gold, which will
protect the white parts.
_Gilding._--The gilding is obtained by any of the various processes
of electrotyping that are known. The only indispensable condition is,
that the surface obtained by the precipitation must not be liable to be
attacked by the weak acid; a solution answering this purpose is made of
10 parts, (by weight), of ferocganide of potassium; 1 part of chloride
of gold, and 1,000 parts of water, used with a galvanic battery. During
the gilding the plate must be turned in several positions, in order to
regulate the metallic deposit. In some cases the gilding may be made more
perfect, if the plate is covered with a thin coating of mercury before
putting in the gilding solution.
When the plate is gilded, it must be heated with the boiling caustic
potash, by the process already indicated for the preparatory engraving,
in order to cleanse it from all the dried oil or ink, which fills the
hollow. The plate is then washed and dried, and when the oil employed has
been thickened with the lampblack, the surface of the plate is rubbed with
crumbs of bread, in order to cleanse and take off the black remaining;
then, the white parts being covered and protected by varnish not liable
to be attacked, and the black parts being uncovered and clean, the plate
can be bitten in by aqua-fortis, according to the ordinary process used by
engravers.
This operation must be used upon the stand, and not by immersing the plate
in the solution.
Before this biting in, if the preparatory engraving has not succeeded
well, and the plate still wants a sufficient grain, it can be given by the
various processes of aquatint engraving.
Before submitting the plate to the operation of printing, in order to
insure an unlimited number of copies, it is necessary, as before stated,
to protect it by a slight coating of copper, which is obtained by the
electrotype process; otherwise the printing would soon wear the plate.
This coating must be kept very thin, but the fineness of the engraving,
and the polish of the white parts, should be destroyed. In this state the
plate can be delivered to the printer.
After a certain number of impressions have been obtained, it will be
perceived that the coating of copper is worn in some places; then this
coating must be removed, and a fresh one applied in its place. For this
purpose, the plate must be purified and cleansed by warm potash, and
plunged in a weak acid, composed as follows:--Water, 600 parts; nitric
acid, 50 parts; nitrous acid of engravers, 5 parts; all in volume.
This acid will dissolve the coating of copper, and the plate being
coppered again, by the same means as before, may be again submitted to
the operation of printing; and as nothing can prevent the success of
a repetition of the same operation, any number of impressions may be
obtained. The coating of copper can also be removed by caustic ammonia.
The Daguerreotype plate engraved by this process, may also be reproduced
and multiplied by the electrotype process, the same as any other engraved
plate.
The essential points of this process, which constitute the present
invention, consist,--
First,--in the discovery and employment of certain properties of a
mixture composed of nitric acid, nitrous acid, and hydrochloric acid, in
detrimental or fixed proportions. The two last mentioned acids may be
employed either in a free state, or combined with alkaline or other bases.
This mixed acid has the property of biting the pure silver, which forms
the black parts of the Daguerreotype picture, without attacking the white
parts formed by the amalgam of mercury.
The result of the action of the biting is, to form on the black part of
the picture an insoluble chloride of silver; and this chloride of silver,
which, when formed, stops the action of the acid, is dissolved by the
ammonia, which allows the biting to continue.
Secondly,--In the discovery of certain properties of a warm solution of
caustic potash, and in the employment of the said solution, by which the
mercury forming the picture is better and deeper amalgamated with the
silver under it, so that many imperceptible points of the amalgam are
affected in such a manner that the action has no action upon them.
Thirdly,--In the discovery and employment of a process which produces a
grain favourable to the engraving, by which the biting on the plate is
rendered deeper. This is effected by filling the parts engraved with a
siccative ink, or any other substance, and then gilding the plate by the
electrotype process: the gold is not deposited on the parts protected by
the ink. When the plate is gilded, the ink is cleansed by the caustic
potash, and the plate may be submitted to the effect of an acid, which
does not attack the coating of gold, but bites only on the silver in the
parts already engraved by the first operation.
Fourthly,--In the employment of a process by which the plate is protected
from the wear of the printing operation. This is effected by covering the
plate before printing, with a slight coating of copper; by the electrotype
process, and when the coating begins to wear, by printing, it is removed
by a weak acid or by ammonia, which dissolves the copper without effecting
the silver under it. The plate is coppered again, and after another
printing, the same operation is repeated, so that a considerable number of
copies may be printed without injury to the engraving.
Enrolled in the Pitty Bag Office, May, 1844.
* * * * *
=INTERESTING EXPERIMENT WITH STRYCHNIA.=
An interesting experiment, illustrative of the poisonous effects of
strychnia, was recently made by Professor Agassiz, at Cambridge. The
subject was a large black bear, about eighteen months old. The animal
was taken when young, and had been kept in captivity for a considerable
period. Professor Agassiz being desirous of killing it for the purpose of
dissection, about three grains of strychnia were administered. The poison,
though extremely bitter was readily swallowed. At the expiration of ten
minutes, no effect having been produced, a second dose of about the same
quantity was also inclosed in a biscuit and offered. The cunning animal
broke open and swallowed the biscuit, but rejected the poison. The first
portion, however, had proved efficacious, and in exactly fifteen minutes
from the time when first administered, the animal was seized with terrible
convulsions, and soon died.
The whole time which elapsed between the taking of the poison and the
death of the animal, did not exceed twenty-five minutes. In order to
alleviate its sufferings and hasten death, a quantity of hydrocyanic acid
was poured upon the nose and mouth of the bear. It did not, however,
produce any sensible effect, and was not apparently taken into the system,
as the animal at the time was nearly dead. But the subsequent effects of
the poison were most remarkable. Although the bear, at the time of death,
was in perfect health and strength, twenty-four hours had not elapsed
before the body was in an advanced stage of decomposition. Indeed the
appearances indicated that the animal had been dead for nearly two months.
The interior of the body, when opened about twenty hours after death,
still retained its warmth in a considerable degree, while an offensive
gas issued from every pore. The blood had not coagulated, the spinal
marrow and nerves were in a semi-fluid state, and the flesh had assumed a
leaden-gray color. The hair of the hide readily came out on being slightly
pulled. No smell of the hydrocyanic acid could be perceived.
The origin of this singular and speedy decomposition is not fully known,
though it is supposed to be due to the agency of the hydrocyanic acid. A
chemical examination of the muscle, brain, nerves, liver and kidneys is
now going on at the Cambridge laboratory, under the direction of Professor
Horsford. One singular fact connected with the spontaneous decomposition
of these parts is, that they all yielded or disengaged hydrosulphuric
acid gas, with the exception of the liver, which did not.--_Annual of
Scientific Discovery._
* * * * *
=NOTICE.=
A few copies only of Volume I. of the Daguerreian Journal can be had by
applying at this office. Price three dollars.
This is the most complete work ever published on the Daguerreian Art.
Orders addressed to the publisher of this Journal.
* * * * *
=THE DAGUERREIAN JOURNAL=
=NEW YORK, JUNE 1, 1851.=
The metal which the Daguerreotypists have most to deal with is silver.
To obtain plates of this perfectly clean and keep them so is one of
the most difficult parts of his art; in order to accomplish it he is
obliged to have resource to circuitous mechanical processes, or to some
chemical means whereby the old surface may be removed, or a new surface
deposited. He uses tripoli and rotten stone, rouge and buffing, fatty
matters, alcohol, ammonia, and nitric acid, for the first purpose; and
electro-plating for the second. The operator must not mistake the object
he has in view. By all his mechanical operations, where friction is
concerned, he obtains a _polished_ surface; but it is not to _polish_
the plate that he uses the buff, and the other materials; the object is
to clean the plate, and the _polish_ of the surface follows as a natural
result. That a polished surface is not necessary for the formation of an
image is evident from photography on paper, and Hyalotype. In these cases
the surfaces do not reflect light; they are not polished; they are merely
clean. The fact of a plate freshly taken out of a cell where silver has
been deposited on it receiving beautiful images, is another proof that
polish is unnecessary for success. What is wanted is a surface of pure
silver, one not coated with the slightest trace of oxide, carbonate, or
sulphuret of silver, or with any impurity derived by contact with foreign
matter. The Daguerreotypist has, then, two objects in view.--1st, to
get a clean surface on his plate; and 2nd, this once obtained, to keep
it so without further alteration. Although silver is classed with gold
and platinum, as one of those metals which do not tarnish or oxidize
readily on exposure to the air, yet it is now well known in practice
what a difference exists in the character of the picture brought out on
a plate recently polished and one set aside even for a few hours. It is
true that the atmosphere alone will not affect or oxidize a plate of
polished silver, but that is only true of a very dry atmosphere; for an
atmosphere which contains even a small amount of moisture in it, will
in a short time dull the surface of the plate. In this instance the
moisture is deposited first, and brings the air into closer contact with
the surface of the metal, promoting the union of the latter with the
oxygen of the air. This is exemplified every day in the case of iron,
which does not rust in dry weather, but when the air begins to deposit
its moisture it rapidly oxydizes. So is it with lead and zinc, but in
a less degree. Pure water has no effect in tarnishing the surface of a
silver plate, but if it contains even a very small quantity of animal or
vegetable matter it darkens the surface in consequence of the presence
of sulphur. The ordinary tarnish of silver is due to the fastening upon
the surface of sulfurous vapors, which are constantly floating in the
air. We are scarcely yet in possession of sufficient facts to justify the
statement that sun-light materially aids in this alteration. We do know
that oxidizement in any substance goes on much more rapidly in sunshine
than under any other circumstances. In the vegetable kingdom it is of
hourly occurrence; but the different effects of shade and shine upon the
oxidizement of plates of metal has not been minutely studied. However this
may be, after a time the silver surface does get coated with a film, of
partly sulphuret, partly oxide, and a complete layer of air, which so
closely attaches itself to the plate that water when poured on it rolls
off and does not wet the surface. It is this film, of air which mechanical
friction and bulling are so serviceable in removing. The tarnish of a
sulphuret is not so readily removed by friction as by ammonia, for the
sulphuret of silver is, to some extent, soluble in ammonia; but as the
sulphuret when present gives a yellowish brown tint to the surface, it is
only then that it is needful, and even a weak solution of commom salt or
hydrodate of potash cleans the surface much quicker.
As nitric acid is the best solvent of silver, so is it the best agent to
remove films of oxide and carbonate from the surface; it does so readily,
effectually, and leaves a clean new surface of silver, similar to a plate
newly prepared, or one which has received a new coating in the electrotype
cell. The acid, however, must be very much diluted, otherwise its local
action is so immediate as to eat down the surface of the plate faster than
it spreads, producing inequalities,--even when left long on, although
diluted, it produces roughness; hence its use has not been happy in many
hands. To such, the longer, but less failing processes of mechanical
action are to be recommended in preference.
* * * * *
Friend Humphrey:--
I have thought for some time past that I would furnish a few thoughts for
the _Daguerreian Journal_, under the head of _General Rumors_. A fear
of injuring the Daguerreian business, by giving an additional publicity
to my discovery, for the present has kept me from this, as well as from
furnishing several other articles.
A _very few_ persons (for the honor of humanity, I am glad the number is
small) have made statements which reflect seriously upon the integrity
and motives of myself and friends. By means of certain legal processes,
of which I am not wholly ignorant, I could do _these gentry_ more simple
justice than by dignifying them by a notice in our Journal, yet I bear
them no ill will, and _for the present_ shall act on the principle that
it is better to suffer wrong than to engage in a quarrel, especially with
men who have so little regard for the feelings and reputation of their
fellows, as to condemn, denounce, and accuse, without discrimination, and
without the slightest knowledge of facts.
The "head and front of my offending" is this--that I _have_, by dint of
unwearied pains and perseverance, succeeded in imprinting the colors of
nature, in all their inimitable glory, upon the metallic surface. The
process, when brought out, it is believed, by the best of judges, will
be an astonishment to, the world, and a delight to our nation; and I
have felt, from the first, that I am but an instrument in the hands of
the Almighty, and am therefore bound in duty, as well as by inclination,
to dispose of the secret in a way to accomplish the greatest amount of
good. In this spirit I have frequently published my unalterable resolve
that my process _shall never be monopolized, or used for the purposes of
extortion_. If I had no other reason for this course, the fact that there
are great numbers of worthy persons engaged in our art, who, like myself,
are poor, this would be sufficient. Various plans have been suggested to
me, for the best possible method of disposing of my discovery. Numerous
gentlemen of high standing, have honored me with personal intercourse and
friendly advice. I have even suffered the claims of courtesy to interfere
with my experiments, and, I believe I have the good will and confidence of
those who have honored me with their visits; but I have never swerved from
my original determination, and have given no person the slightest reason
to think otherwise.
In view of these _facts_, it is not strange that I should feel annoyed at
the various rumors to which I refer, and some of the intimations which
have been thrown out, I _feel_ are but poor pay for my having nearly,
if not quite, ruined my health, by laboring from morn till midnight for
the good of others. More especially have I been _grieved_ that _some
of my best friends, and the best friends of the fraternity_, should be
accused of having outwitted me, and drawn me into obligations to them
which would compel me to pursue a grasping course. Now, it is true that
certain gentlemen have, from the most honorable motives, made me very
liberal offers of aid, and it is also true that my mind is about settled
in regard to the parties with whom I shall act; but it is not true that I
am under obligations to give notoriety to my _business affairs_, and it is
certain that I shall not do so until I see fit. Neither is there the least
foundation for the assertion that I am committed to any person. There
confidence in me is not based on paper, but on a much surer foundation.
The process which I have been so fortunate as to discover, is _my
property_. No man on earth has any claim, upon it, and I have a perfect
right to dispose of it as I please, in case I do not interfere with the
rights of others. This, I think, is the philosophy of _Professor Morse_,
so admirably and clearly expressed in the last number of the Journal. This
distinguished man recently favored me with a visit, and, in the course
of the interview, shed much light on this subject for which I feel truly
thankful.
My intention has been, and is, to _do right_, and I believe the majority
approve of the course I have pursued thus far. The many marks of
approbation I have received from eminent men, both in this profession
and others, is truly encouraging to me in my poor health and arduous
labors, and will never be forgotten. Those who seem to possess a different
spirit, and who have apparently endeavored to hedge up my way by means
of "rumors," "new discoveries," "threats," &c., have my forgiveness, and
I trust that, in future, if they are not disposed to aid, they will do
nothing to hinder me.
The brotherhood have nobly aided me, by purchasing my book. My sales are
exceeding my most sanguine expectations, and are placing me on a footing
to make me _feel that I am free_. All may be assured that I shall not
use my freedom "as a cloak," but to serve their interests, of which both
myself and friends hope to give them _full proof_ hereafter.
Now that I have been compelled to close my doors against visitors, I would
state that I am doing my utmost to bring out my process in a short time,
and I will hereafter give, in the _Daguerreian Journal_, such notices of
my success as will meet the wishes of the public, as well as the interest
of our fraternity,
I am yours &c.,
L. L. Hill.
Westkill, Greene Co., N. Y.,
_May 30, 1851._