VOL. II.                   JUNE 1, 1851.                   NO. 2.

SUBJECT TO NEWSPAPER POSTAGE.—See 3d page cover.

CONTENTS.

S. J. THOMPSON,

WOULD most respectfully announce to the public, that he has one of the best sky-lights in the United States, and is prepared to execute Daguerreotypes. Likenesses of all sizes, put up in every style of the Art.

No. 57 State-street, Albany, N. Y.

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J. H. WHITEHURST'S

ELECTRO DAGUERREOTYPES,

Galleries, 207 Baltimore Street, Baltimore,

Broadway, New York, 77 Main street, Richmond, Va., Main street, Norfolk, Va., Sycamore street, Petersburg, Va., Main street, Lynchburg, Va., Pennsylvania Avenue, Washington city. Likenesses taken equally well in all weather.

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J. D. WELLS,

DAGUERREIAN ARTIST, No. 6 Kirkland's Block, Main Street; Northampton, Mass. Likenesses taken by a sky-light connected with a beautiful side-light. Pictures put up in all styles of the Art. Plates, Cases, Lockets, Frames, and all kinds of Daguerreotype Stock for sale.

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J. E. MARTIN,

"EXCELSIOR ROOMS" Jefferson Avenue and Odd Fellows' Hall, Detroit. Daguerreotype Likenesses taken in every style of the Art.

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HARRISON'S CAMERAS.

The attention of those about purchasing instruments, is directed to the following recommendation from one of the oldest operators in the country, and one who has been "tried in the furnace" of experience:

Waterbury, Ct., April 1, 1851.

C. C. Harrison,

Dear Sir,—It affords me much pleasure, after giving the instrument I purchased of you last week a fair trial, and having had eleven years experience as an operator, to be enabled to bear testimony to the superiority of your Cameras over all others, not excepting those made by "Voightlander & Sohn," for the sale of which I was sometime agent at Boston.

Yours respectfully,
      Albert Litch,
Formerly of the firm of Litch & Whipple, Boston, Mass.

THE

DAGUERREIAN JOURNAL.

SOME EXPERIMENTS AND REMARKS

ON THE CHANGES WHICH BODIES ARE CAPABLE OF UNDERGOING IN DARKNESS, AND ON THE AGENT PRODUCING THESE CHANGES.

BY ROBERT HUNT.

[Concluded.]

With the view of testing Dr. Draper's results, I carefully iodized two silver plates and exposed them to light. I then placed them so that half of one plate was covered by half of the other, and allowed them to remain in the dark 1-24th of an inch apart for four hours. On mercurialization I could not detect the slightest difference between the covered and uncovered portions of either of the plates.

Another silver plate was iodized and exposed to light. It was then placed in the dark wish a sensitive plate which had been carefully kept from the light, 1-16th of an inch above it, and a small engraving placed between them. They were allowed to remain thus for six hours. When exposed to the vapor of mercury, the plate which had been subjected to the light whitened all over, and the space occupied by the engraving was distinctly marked by lines of vapor thicker than the other parts. The plate which had been preserved in the dark was scarcely at all influenced by the vapor, except on those parts which had been touched by the supports of card-board on which it rested. These were so arranged that no radiation could have influenced those parts of the plates.

An iodized silver plate was placed in the dark with a little fine string coiled over parts of it, and a polished silver plate supported 1-8th of an inch above it. After four hours both plates were subjected to mercurial vapor. On the iodized plate the deposit of vapor was uniform, although slight; but on the superposed plate of silver a strong and beautiful image of the string on the under plate became visible. I found that neither of the two iodized plates had lost their sensitiveness by the operations to which they had been subjected in the dark.

Hoping to detect some evidence of the process by which these singular results were produced, I instituted a series of experiments, of which the following are some of the most interesting results.

A. A silver plate was iodized, a piece of card was placed upon it, and a well-polished mercurial plate (amalgamated copper) was suspended 1-8th of an inch above it, and left in this state for a night. The space on the silver plate corresponding with the mercurial plate, except under the card, was nearly freed of its iodine, which had evidently combined with the mercury on the upper plate. On exposing the mercurial plate to the vapor of mercury the image of the card was rendered visible, the vapor covering every part of the plate except that opposite the card. The silver plate received the vapor only on those parts which were not influenced by the mercurial plate. The upper plate was suspended by strings; these were faithfully imaged on both plates; by a thick line of mercurial vapor on the under plate, by the absence of it in the upper one.

B. An iodized silvered plate was exposed to light until brown, and a mercurial plate suspended above it for twelve hours. The browned silver plate was whitened, and all the irregularities of the mercurial plate strikingly marked on it: the mercurial plate was slightly tarnished. On rubbing the silvered plate it was found that the silver was removed more readily over the whitened portion, but had lost none of its adhesion in other parts.

C. Over an iodized silver plate, plates of gold, platina, silver, brass, copper, copper amalgamated, and zinc were placed at the distance of 1-8th of an inch. After three hours the amalgamated plate had made a decidedly visible impression on the silver one. On exposure to vapor, the mercury lodged on every part of the plate except that affected by the mercurial plate; some irregularities were observed, but none which could be decidedly traced to the other metals in juxtaposition. I have some evidence that different metals near each other seriously interfere with each other's influence.

D. A mercurial plate was iodized, and another mercurial plate placed 1-8th of an inch above it. The upper plate became covered with a bright yellow film; and on exposing them to mercurial vapor, marks became apparent which corresponded with those in the opposite plate.

E. A silver plate was iodized and placed in the dark with an engraving, face down, upon it. An amalgamated copper plate was laid on this, and left for fifteen hours. The mercurial plate was reddened, and on exposure to the vapor of mercury, a very nice impression of the engraving was brought out, it having been effected through the thickness of the paper. On the silvered plate the space covered by the paper was well marked; but vaporization produced no trace of the engraving. The space beyond the paper was rendered white. It was curious that both plates had several spots which corresponded, particularly two, distinguished by a well-defined circle and a comet-like appendage, in length ten times the diameter of the circle. These spots could not be traced to anything visible in the print or either of the plates, and must, I think, be referred to some electrical influence. I find it indeed commonly the case, that the plates, after being subjected to these kind of experiments a few times, become mottled, or present on their polished faces all the appearances of a finely-grained wood, and in this state they are less susceptible of receiving any impression than when not so.

F. A silver plate was iodized and placed upon an engraving laid on a brightly polished mercurial plate, and left in the dark for twenty-four hours. The mercurial plate was turned brown, and the silver plate was left in the same state as if it had been exposed to sunshine, being brown and black. Neither of these plates gave a copy of the picture.

G. A mercurial plate was iodized, and above it was placed a plate of polished iron, a disc of paper being first laid on the mercurial plate, and they were left in this state for some hours. On exposing the iron plate to mercurial vapor, it was abundantly lodged over that space opposite the paper disc, but not at all on the other parts. The mercurial plate was attacked by vapor over every part but that which the paper disc protected.

Lead and zinc plates were used instead of the iron one, with nearly similar results.

H. A Daguerreotype was taken, and without removing the iodine a mercurial plate was placed a little above it, and left for ten hours. When removed, well-defined traces of the Daguerreotype picture were evident on the mercurial plate, which leads me to hope that by careful manipulation we may succeed in multiplying these beautiful productions by an easy method.

I became desirous of ascertaining whether the mercurial plates would produce any change upon the precipitated iodide of silver. I find by many experiments, that if the iodide of silver is pure, no more change is produced than is produced upon it by diffused light; but if it is rendered sensitive by a trace of the nitrate of silver, it is then darkened as by solar influence.

Sensitive iodide of silver being placed upon a plate of glass, a mercurial plate was fixed 1-8th of an inch above it. In three days the iodide of silver had become a deep brown, almost a black, and the mercurial plate was covered with the yellow iodide of mercury. Nitric acid dissolved the dark portion of the silver salt, as did also ammonia, on which was formed Faraday's oxide of silver, thereby proving the change, either by a primary or a secondary process, of the iodide into the oxide of silver. This experiment has been repeated at least a dozen times, and always with the same results. If a little heap of the iodide of silver is placed under a mercurial plate, it is exceedingly interesting to witness the gradual formation of the very beautiful colored rings on the mercury in the progress of its conversion into an iodide. By prolonged action the yellow iodide passes into the bright red biniodide of mercury. I have some experiments now in hand, which convince me that similar chemical changes are to be effected through considerable spaces. I have succeeded in decomposing the iodide of copper and the iodide of gold by mercurial plates placed nearly a quarter of an inch above them.

I have an extensive record of results similar to those I have now detailed, all of them showing that the changes brought about by this mysterious agent, whether it be heat, light, or an undiscovered element, cannot be referred to those rays which the admirable researches of Sir John Herschel have shown to be the operative ones in producing the photographic phenomena which have so interested the world by their novel beauty, and which professor Draper includes within his general term—tithonicity. With regard to the detithonizing influence of the gases mentioned by Dr. Draper in his paper in your March number, I can only consider the results, which I find to be as he has stated, as the simple reconversion of the decomposed iodide of silver into another definite chemical compound. An iodized plate is exposed to light, the iodide of silver or other sensitive salt is decomposed, and in a state to receive mercurial vapor. It is now passed through an atmosphere of iodine, of chlorine, of bromine, or of nitrous gas. Chemists are well aware of the surprising energy with which these bodies attack the metals, consequently the exposure of a moment is quite sufficient to convert the surface which has undergone a change, into an iodide, chloride, bromite, or nitrite of silver. I certainly cannot see the necessity of going so far out of our way for an explanation of this effect as Dr. Draper has done.

I fear I have already occupied too much of your valuable space, or I might be inclined to trespass further. I shall, however drop my pen for the present, again assuring you that I only desire to keep the image of Truth which is just shadowing our path, as free as possible from mists which might in any way obscure it.—Philosophical Magazine, 1843.

Railroad to the Pacific.—Forest Shepherd, of Sacramento City, says it is now ascertained almost beyond doubt, that a railroad can be constructed from the Mississippi to the Pacific, without crossing any mountains, or meeting more impediment from snow than between Albany and Boston.

EXPERIMENTS ON THE COLORED FILMS

FORMED BY IODINE, BROMINE, AND CHLORINE
UPON VARIOUS METALS.

BY AUGUSTUS WALLER, M. D.

In a paper presented by me to the Academy of Sciences of Paris, an extract from which may be seen in the Comptes Rendus for October 5, 1840, I first demonstrated the error committed in ascribing to the iodide of silver alone the power of fixing the vapors of mercury, after it had been exposed to the action of light. Instead of this property being exclusively confined to a film of iodide of silver, as obtained in the process of M. Daguerre, I found that it existed in many other substances when presented to the action of light in the state of thin films, viz. by the bromide and chloride of silver; by the oxide, bromide, iodide and chloride of copper, and some others; all these, however, possessing less sensibility than the iodide of silver of Daguerre, and therefore less available for the reproduction of the images of the camera than the compound originally discovered by that gentleman. The iodide of Daguerre was found already too little sensitive to the influence of light in this climate, especially when applied to the reproduction of the image of animate objects, so that those films discovered by me seemed still less suitable to be employed for that purpose; this objection has, however, been completely removed by recent improvements, more particularly those of M. Claudet, who effected this principally by combining the original discovery of Daguerre with those mentioned above as having been subsequently made by myself. Pursuing the first stage of Daguerre's process, he obtained the film of iodide of silver, and added to this another film of bromide, either in a simple state,—as practised in my experiments published more than six months before—or after two of these substances had been combined together, as the chloride of iodine and the bromide of iodine, which he was the first to employ.

These colored films, however, merit attention independently of the purposes to which they may be applied in photography: the beauty of some of the phenomena themselves is peculiarly attractive; the numerous changes of color they undergo, either by a variation in the thickness of the film, or by the action of light, assign them a place among the most curious facts of science, and the extreme facility with which they are obtained adds to the interest they excite.

Impressed with these ideas, I was induced to pursue a train of investigation on this subject; among the results of which, one of the most interesting was a new method of making colored rings, like those generally known under the name of "Newton's colored rings," on many of the metals, by the same chemical process as that employed for forming the films of uniform thickness in photography. In order to procure these colored rings, and at the same time to show the identity of the origin of the colors with those of the ordinary transparent films, that is, as residing simply in the thickness of the lamina and not dependent on the ordinary cause of color, we have but to place a piece of iodine on a well-polished surface of silver or copper, and in a short time we find around the iodine a series of colored zones of the various tints of the spectrum, and approaching in a greater or less degree to the form of a circle, according as they have been more or less disturbed in their formation by currents of the surrounding air. In order that they may be perfectly regular, as large as possible, and with tints undisturbed by the action of light, it is necessary to place a piece of iodine in the centre of a well-polished plate, as before described; this is then to be shaded by an opake screen superimposed a few lines from the surface to cause the vapors which would otherwise ascend and partially escape, to expand over its silver surface. Colored rings may be formed in the same manner by bromine and chlorine and the various combinations of these bodies with each other, except that for those that are gaseous or liquid it is requisite to pay a little attention to the manner of disengaging them on the surface of the metal, either by passing them through a glass tube, or by some other contrivance easy to execute.

These rings correspond to those formed by reflected light in Newton's experiments, with this difference, however, that in the colored films of the soap bubble, and in those formed by the glass lenses, the thinest film is in the centre; whilst in these rings, obtained by chemical action, it exists at the circumference, as is the case with the colored rings of Nobili. In watching the formation of these phenomena, at first are seen two or three very small circles, which appear almost as soon as the iodine and the metal are placed in contact with each other; as the experiment continues, the circumference of these circles become gradually greater; whilst the external colors extend themselves over a great space, those of the centre grow fainter; red and green now only remain visible, and these at last, when the film has attained a certain thickness, in their turn also give place to a dull coating of brown.

The formation of these rings evidently depends on the vaporization of the iodine from the solid nucleus. The variety in color and extent of these zones is caused by the difference between the strength of the vapor at the centre and the circumference of the iodic atmosphere whilst expanding over so large a surface. In the metal thus combining with the vapor, we have to consider,—1, the force of the vapor of different distances from the centre; 2, the obstacle which a film of iodine, once formed, opposes to any further action between the iodine and the metal.

This experiment may be varied in different ways: two pieces of iodine of about the same size, placed at a small distance from each other on a silver plate, form separate colored circles, until these come in contact at their circumferences, when the two systems will slowly coalesce and produce one common outline of the form of an ellipsis.

As the colors formed on various metals by the above-mentioned agents are very similar to one another, it may be sufficient to examine in particular those produced on silver by iodine.

The external film of the iodide of silver rings, which corresponds to the central black spot in those of Newton, is completely invisible, it being impossible to perceive any difference between the parts so covered and those where the metal is intact; but by exposing half the plate to the influence of light, whilst the other part remains covered, the silver is then found darkened far beyond the limits of the external gold-colored zone, where previously the surface was perfectly clear. The dark film thus rendered apparent is now liable to be rubbed off by the slightest friction, whereas before it was very adherent to the subjacent surface. The first zone is of a pale gold color, which assumes a deeper tint as the thickness of the film increases: the second zone is blue, the third white: after these appear the different colors of the spectrum in regular succession, as in the films studied by Newton and others, viz. yellow, orange, red, blue green, yellow &c.

The presence of the golden-colored zone in the place mentioned is worthy of remark, as in the tables of Newton of the colors presented by films of various thicknesses, the blue is stated as immediately following the black. The same gold film is the first which appears on most metals when their surface is attacked in this manner. Chlorine and bromine on silver; oxygen on steel; chlorine and bromine on titanium, bismuth, &c., commence their colors in the same way. Copper, however, is in one respect an exception, this metal first becoming of a dark red, which increases to a ruddy brown and then changes into blue. This deviation is fully accounted for by the color of the copper itself. With this single particularity, this metal undergoes the same alterations as the others.

The action of light on the different colors of the iodide of silver is very interesting: the most correct way of studying this is to protect one half of a system of colored rings by an opake screen, while the other half is exposed for a short time to the influence of the solar rays. The golden zone undergoes the greatest change; at first it grows darker, then red, and at length is converted into a beautiful green. The blue film, which comes next in thickness, suffers considerable alteration in its tint, assuming a much deeper and more brilliant shade; the rest of the colors appear to be similarly affected by the action of light, though to a very slight degree, acquiring a trifling accession in their brilliancy. It has already been remarked that light destroys the adherence of the external invisible film; the same thing obtains with the second or gold-colored film, which turns green, but only to a certain depth of the film, as may be proved by slightly rubbing the part thus altered; the green color is then seen to disappear, and beneath the pulverulent portion thus removed is found the gold color, having almost the same appearance as before the plate had been exposed. As this experiment may be repeated several times with the same results, it shows to how inconceivably small a depth the light has acted to produce this effect.

To ascertain what would take place on augmenting the thickness of the portion turned green, and the adherence of which was destroy ed, a piece of iodine was placed on the plate so that its vapor, by expanding, might arrive upon the green, at the same time the whole being kept from the light; the result was that the additional film combined with the one already existing, producing a blue, being the color which would have resulted by the combination of the unaltered yellow films. I have found no chemical substance possessing the power of arresting, or in any way influencing these changes of color; strong adds, provided they do not attack the silver—for then, of course, the experiment would be destroyed,—and alkalies in concentrated solution, allow the action of light to go on as usual. The hyposulphate of soda, and ammonia in solution have no longer the power of dissolving the green film as they had before the action of light.

When the plate is left still longer exposed, after the changes above stated have taken place, the colors become more faint, and within the zone of green a white cloudy film is caused by the light, which, as it increases, veils the spectral colors beneath.

The knowledge we at present possess in chemistry of the affinities with which different bodies are endowed for combining with each other is but very imperfect, and the causes which complicate most chemical phenomena are so numerous, that it is scarcely possible to compare any two chemical actions to each other. Most of the facts upon which chemical science is founded, are acquired either by bringing the two bodies destined to act on each other into contact by dissolving them in a liquid, or by subjecting them to a temperature more or less elevated.

In the first of these methods, we are so far from being able to calculate the force of the chemical powers called into play, that Berthollet was induced to deny the existence of chemical power in the various phenomena of solution and precipitation of saline substances, and according to him what is called insolubility in a body is merely the result of its strength of cohesion, an entirely physical property.

When the intervention of caloric is required, the effects are still more complicated, as they vary according to the intensity of the heat employed, and the time its action is exerted; besides, the chemical action, when it does take place, is frequently so instantaneous that it is impossible in our present state of science to imagine any means by which it might be measured. In the combination of the three bodies, iodine, bromine and chlorine, with the metals, however, most of these objections cease to exist, or may be easily avoided. As their vapors combine with the metallic surfaces at the ordinary temperature, they are all of them in the same circumstances in that respect; and if the temperature should be required more elevated, the gasiform state of these substances, iodine not excepted, enables us to submit the metals to be experimented upon all at the same time to the same influence. If, therefore, it were possible to reduce the metallic substances into fine powders the particles of which were of the same dimensions, by acting upon them with either of these vapors, an idea might be formed of the affinities which produce their binary compounds by the increased weight acquired by the powders in this process; but the difference which exists in the physical properties of the various metals would preclude the possibility of any near approach to accuracy in this mode of proceeding; but by acting on the polished metallic surfaces, as in the preceding experiments, all the advantages offered by the process with the powders are included, whilst several of the difficulties are removed.

As the film of the compound augments, it undergoes the various changes of color which take place in all transparent films, thus affording a means of ascertaining the absolute thickness obtained in different circumstances, when it would be difficult to detect the slightest difference in weight by means of the most delicate balance. The depth of this coating may be ascertained when either the index of refraction of the compound itself is known, or if the angle of polarized light is given by means of the law discovered by Sir David Brewster, between the tangent of the angle of polarization, and the index of refraction. The most convenient way which occurred to me of performing these experiments, was the employment of a bell-glass within which some iodine is fixed at the top; this apparatus being placed over the metal to be acted on, the experiment may be watched in all its progress, and the action can be retarded or accelerated at pleasure by varying the interval of the iodine from the metal, or by interposing at some distance from its surface a disc of paper so as to cause the vapors of iodine to pass through it. Bromine may be made use of likewise by pouring a few drops of it over some carded cotton, and using it in a similar manner with the iodine. In respect to chlorine, it is most convenient to disengage it slowly by dropping a little sulphuric acid upon some chlorinated lime.

In illustration of the objects of this mode of experimenting, I will aduce some of the results it has given me with various metals. Some of the experiments below were performed before I had the idea of watching the progress of the combination through a transparent medium; they are therefore less exact than they might otherwise have been: but I have preferred stating them as I had inserted them in my note-book before I had conceived any idea as to their probable utility in the elucidation of chemical affinity, and when I intended them for other purposes, which I shall hereafter explain.

Iodine with Silver and Copper.

Bromine with Silver and Copper.

Chlorine with Silver and Copper.

Iodine with Titanium.

Bromine with Titanium.

Chlorine with Titanium and Copper.

Iodine with Bismuth and Silver.

Iodine with Mercury.

It is impossible to estimate the affinity between mercury and iodine by means of the colored films, because, on combining, these two substances merely cause a dirty white appearance on the surface of the latter. Their combining affinity appears to be considerable, for when exposed together with silver the action produced with both was red at the edges, little altered in color; on the rest of its surface a dull white film, in the midst of which were seen several dark spots, where the metal was apparently unaltered.

Bromine with Mercury and Copper.

Chlorine with Mercury and Copper.

Bromine with Bismuth and Silver.