From the foregoing extracts from the first lecture on photography that ever was delivered or published, it will be seen that those two eminent philosophers and experimentalists despaired of obtaining pictures in the camera-obscura, and of rendering the pictures obtained by superposition, or cast shadows, in any degree permanent, and that they were utterly ignorant and destitute of any fixing agents. No wonder, then, that all further attempts to pursue these experiments should, for a time, be abandoned in England. Although Thomas Wedgwood’s discoveries were not published until 1802, he obtained his first results in 1791, and does not appear to have made any appreciable advance during the remainder of his life. He was born in 1771, and died in 1805. Sir Humphry Davy was born at Penzance 1778, and died at Geneva in 1828, so that neither of them lived to see the realization of their hopes.

From the time that Wedgwood and Davy relinquished their investigation, the subject appears to have lain dormant until 1814, when Joseph Nicéphore Niépce, of Chalons-sur-Saône, commenced a series of experiments with various resins, with the object of securing or retaining in a permanent state the pictures produced in the camera-obscura, and in 1824, L. J. M. Daguerre turned his attention to the same subject. These two investigators appear to have carried on their experiments in different ways, and in total ignorance of the existence and pursuits of the other, until the year 1826, when they accidentally became acquainted with each other and the nature of their investigations. Their introduction and reciprocal admiration did not, however, induce them to exchange their ideas, or reveal the extent of their success in the researches on which they were occupied, and which both were pursuing so secretly and guardedly. They each preserved a marked reticence on the subject for a considerable time, and it was not until a deed of partnership was executed between them that they confided their hopes and fears, their failures with this substance, and their prospects of success with that; and even after the execution of the deed of partnership they seem to have jealously withheld as much of their knowledge as they decently could under the circumstances.

Towards the close of 1827 M. Niépce visited England, and we receive the first intimation of his success in the production of light-drawn pictures from a note addressed to Mr. Bauer, of Kew. It is rather curious and flattering to find that the earliest intimation of the Frenchman’s success is given in England. The note which M. Niépce wrote to Mr. Bauer is in French, but the following is a translation of the interesting announcement:—“Kew, 19th November, 1827. Sir,—When I left France to reside here, I was engaged in researches on the way to retain the image of objects by the action of light. I have obtained some results which make me eager to proceed.... Nicéphore Niépce.” This is the first recorded announcement of his partial success.

In the following December he communicated with the Royal Society of London, and showed several pictures on metal plates. Most of these pictures were specimens of his successful experiments with various resins, and the subjects were rendered visible to the extent which the light had assisted in hardening portions of the resin-covered plates. Some were etchings, and had been subjected to the action of acid after the design had been impressed by the action of light. Several of these specimens, I believe, are still extant, and may be seen on application to the proper official at the British Museum. M. Niépce named these results of his researches Heliography, and Mr. Robert Hunt gives their number, and a description of each subject, in his work entitled, “Researches on Light.” M. Niépce met with some disappointment in England on account of the Royal Society refusing to receive his communication as a secret, and he returned to France rather hurriedly. In a letter dated “Chalons-sur-Saône, 1st March, 1828,” he says, “We arrived here 26th February”; and, in a letter written by Daguerre, February 3rd, 1828, we find that savant consoling his brother experimentalist for his lack of encouragement in England.

In December, 1829, the two French investigators joined issue by executing a deed of co-partnery, in which they agreed to prosecute their researches in future in mutual confidence and for their joint advantage; but their interchange of thought and experience does not appear to have been of much value or advantage to the other; for an examination of the correspondence between MM. Niépce and Daguerre tends to show that the one somewhat annoyed the other by sticking to his resins, and the other one by recommending the use of iodine. M. Niépce somewhat ungraciously expresses regret at having wasted so much time in experimenting with iodine at M. Daguerre’s suggestion, but ultimate results fully justified Daguerre’s recommendation, and proved that he was then on the right track, while M. Niépce’s experiments with resins, asphaltum, and other substances terminated in nothing but tedious manipulations, lengthy exposures, and unsatisfactory results. To M. Niépce, most unquestionably, is due the honour of having produced the first permanent sun-pictures, for we have seen that those obtained by Wedgwood and Davy were as fleeting as a shadow, while those exhibited by M. Niépce in 1827 are still in their original condition, and, imperfect as they are, they are likely to retain their permanency for ever. Their fault lay in neither possessing beauty nor commercial applicability.

As M. Niépce died at Chalons-sur-Saône in 1833, and does not appear to have improved his process much, if any, after entering into partnership with M. Daguerre, and as I may not have occasion to allude to him or his researches again, I think this will be the most fitting place to give a brief description of his process, and his share in the labours of bringing up the wonderful baby of science, afterwards named Photography, to a safe and ineffaceable period of its existence.

The Heliographic process of M. Niépce consists of a solution of asphaltum, bitumen of Judea, being spread on metal or glass plates, submitted to the action of light either by superposition or in the camera, and the unaffected parts dissolved away afterwards by means of a suitable solvent. But, in case any student of photography should like to produce one of the first form of permanent sun-pictures, I shall give here the details of M. Niépce’s own modus operandi for preparing the solution of bitumen and coating the plate:—

“I about half fill a wine-glass with this pulverised bitumen; I pour upon it, drop by drop, the essential oil of lavender until the bitumen is completely saturated. I afterwards add as much more of the essential oil as causes the whole to stand about three lines above the mixture, which is then covered and submitted to a gentle heat until the essential oil is fully impregnated with the colouring matter of the bitumen. If this varnish is not of the required consistency, it is to be allowed to evaporate slowly, without heat, in a shallow dish, care being taken to protect it from moisture, by which it is injured and at last decomposed. In winter, or in rainy weather, the precaution is doubly necessary. A tablet of plated silver, or well cleaned and warm glass, is to be highly polished, on which a thin coating of the varnish is to be applied cold, with a light roll of very soft skin; this will impart to it a fine vermilion colour, and cover it with a very thin and equal coating. The plate is then placed upon heated iron, which is wrapped round with several folds of paper, from which, by this method, all moisture had been previously expelled. When the varnish has ceased to simmer, the plate is withdrawn from the heat, and left to cool and dry in a gentle temperature, and protected from a damp atmosphere. In this part of the operation a light disc of metal, with a handle in the centre, should be held before the mouth, in order to condense the moisture of the breath.”

In the foregoing description it will be observed how much importance M. Niépce attached to the necessity of protecting the solution and prepared plate from moisture, and that no precautions are given concerning the effect of white light. It must be remembered, however, that the material employed was very insensitive, requiring many hours of exposure either in the camera or under a print or drawing placed in contact with the prepared surface, and consequently such precaution might not have been deemed necessary. Probably M. Niépce worked in a subdued light, but there can be no doubt about the necessity of conducting both the foregoing operations in yellow light. Had M. Niépce performed his operations in a non-actinic light, the plates would certainly have been more sensitive, and the unacted-on parts would have been more soluble; thus rendering both the time of exposure and development more rapid.

After the plate was prepared and dried, it was exposed in the camera, or by superposition, under a print, or other suitable subject, that would lie flat. For the latter, an exposure of two or three hours in bright sunshine was necessary, and the former required six or eight hours in a strong light. Even those prolonged exposures did not produce a visible image, and the resultant picture was not revealed to view until after a tedious process of dissolving, for it could scarcely be called development. M. Niépce himself says, “The next operation then is to disengage the shrouded imagery, and this is accomplished by a solvent.” The solvent consisted of one measure of the essential oil of lavender and ten of oil of white petroleum or benzole. On removing the tablet from the camera or other object, it was plunged into a bath of the above solvent, and left there until the parts not hardened by light were dissolved. When the picture was fully revealed, it was placed at an angle to drain, and finished by washing it in water.

Except for the purpose of after-etching, M. Niépce’s process was of little commercial value then, but it has since been of some service in the practice of photo-lithography. That, I think, is the fullest extent of the commercial or artistic advantages derived from the utmost success of M. Niépce’s discoveries; but what he considered his failures, the fact that he employed copper plates coated with silver for his heliographic tablets, and endeavoured to darken the clean or clear parts of the silvered plates with the fumes of iodine for the sake of contrast only, may be safely accepted as the foundation of Daguerre’s ultimate success in discovering the extremely beautiful and workable process known as the Daguerreotype.

M. Niépce appears to have done very little more towards perfecting the heliographic process after joining Daguerre; but the latter effected some improvements, and substituted for the bitumen of Judea the residuum obtained by evaporating the essential oil of lavender, without, however, attaining any important advance in that direction. After the death of M. Nicéphore Niépce, a new agreement was entered into by his son, M. Isidore Niépce, and M. Daguerre, and we must leave those two experimentalists pursuing their discoveries in France while we return to England to pick up the chronological links that unite the history of this wonderful discovery with the time that it was abandoned by Wedgwood and Davy, and the period of its startling and brilliant realization.

In 1834, Mr. Henry Fox Talbot, of Lacock Abbey, Wilts, “began to put in practice,” as he informs us in his memoir read before the Royal Society, a method which he “had devised some time previously, for employing to purposes of utility the very curious property which has been long known to chemists to be possessed by the nitrate of silver—namely, to discolouration when exposed to the violet rays of light.” The statement just quoted places us at once on the debateable ground of our subject, and compels us to pause and consider to what extent photography is indebted to Mr. Talbot for its further development at this period and five years subsequently. In the first place, it is not to be supposed for a moment that a man of Mr. Talbot’s position and education could possibly be ignorant of what had been done by Mr. Thomas Wedgwood and Sir Humphry Davy. Their experiments were published in the Journal of the Royal Institution of Great Britain in June, 1802, and Mr. Talbot or some of his friends could not have failed to have seen or heard of those published details; and, in the second place, a comparison between the last records of Wedgwood and Davy’s experiments, and the first published details of Mr. Talbot’s process, shows not only that the two processes are identically the same, but that Mr. Talbot published his process before he had made a single step in advance of Wedgwood and Davy’s discoveries; and that his fixing solution was not a fixer at all, but simply a retardant that delayed the gradual disappearance of the picture only a short time longer. Mr. Talbot has generally been credited with the honour of producing the first permanent sun-pictures on paper; but there are grave reasons for doubting the justice of that honour being entirely, if at all, due to him, and the following facts and extracts will probably tend to set that question at rest, and transfer the laurel to another brow.

To the late Rev. J. B. Reade is incontestably due the honour of having first applied tannin as an accelerator, and hyposulphite of soda as a fixing agent, to the production and retention of light-produced pictures; and having first obtained an ineffaceable photograph upon paper. Mr. Talbot’s gallate of silver process was not patented or published till 1841; whereas the Rev. J. B. Reade produced paper negatives by means of gallic acid and nitrate of silver in 1837. It will be remembered that Mr. Wedgwood had discovered and stated that the chloride of silver was more sensitive when applied to white leather, and Mr. Reade, by inductive reasoning, came to the conclusion that tanned paper and silver would be more sensitive to light than ordinary paper coated with nitrate of silver could possibly be. As the reverend philosopher’s ideas on that subject are probably the first that ever impregnated the mind of man, and as his experiments and observations are the very earliest in the pursuit of a gallic acid accelerator and developer, I will give them in his own words.—“No one can dispute my claim to be the first to suggest the use of gallic acid as a sensitiser for prepared paper, and hyposulphite of soda as a fixer. These are the keystones of the arch at which Davy and Young had laboured—or, as I may say in the language of another science, we may vary the tones as we please, but here is the fundamental base. My use of gallate of silver was the result of an inference from Wedgwood’s experiments with leather, ‘which is more readily acted upon than paper’ (Journal of the Royal Institution, vol. i., p. 171). Mrs. Reade was so good as to give me a pair of light-coloured leather gloves, that I might repeat Wedgwood’s experiment, and, as my friend Mr. Ackerman reminds me, her little objection to let me have a second pair led me to say, ‘Then I will tan paper.’ Accordingly I used an infusion of galls in the first instance in the early part of the year 1837, when I was engaged in taking photographs of microscopic objects. By a new arrangement of lenses in the solar microscope, I produced a convergence of the rays of light, while the rays of heat, owing to their different refractions, were parallel or divergent. This fortunate dispersion of the calorific rays enabled me to use objects mounted in balsam, as well as cemented achromatic object glasses; and, indeed, such was the coolness of the illumination, that even infusoria in single drops of water were perfectly happy and playful (vide abstracts of the ‘Philosophical Transactions,’ December 22nd, 1836). The continued expense of an artist—though, at first, I employed my friend, Lens Aldons—to copy the pictures on the screen was out of the question. I therefore fell back, but without any sanguine expectations as to the result, upon the photographic process adopted by Wedgwood, with which I happened to be well acquainted. It was a weary while, however, before any satisfactory impression was made, either on chloride or nitrate paper. I succeeded better with the leather; but my fortunate inability to replenish the little stock of this latter article induced me to apply the tannin solution to paper, and thus I was at once placed, by a very decided step, in advance of earlier experimenters, and I had the pleasure of succeeding where Talbot acknowledges that he failed.

“Naturally enough, the solution which I used at first was too strong, but, if you have ever been in what I may call the agony of a find, you can conceive my sensations on witnessing the unwilling paper become in a few seconds almost as black as my hat. There was just a passing glimpse of outline, ‘and in a moment all was dark.’ It was evident, however, that I was in possession of all, and more than all, I wanted, and that the dilution of so powerful an accelerator would probably give successful results. The large amount of dilution greatly surprised me; and, indeed, before I obtained a satisfactory picture, the quantity of gallic acid in the infusion must have been quite homœopathic; but this is in exact accordance with modern practice and known laws. In reference to this point, Sir John Herschel, writing from Slough, in April, 1840, says to Mr. Redman, then of Peckham (where I had resided), ‘I am surprised at the weak solution employed, and how, with such, you have been able to get a depth of shadow sufficient for so very sharp a re-transfer is to me marvellous.’ I may speak of Mr. Redmond as a photographic pupil of mine, and at my request, he communicated the process to Sir John, which, ‘on account of the extreme clearness and sharpness of the results,’ to use Sir John’s words, much interested him.

“Dr. Diamond also, whose labours are universally appreciated, first saw my early attempts at Peckham in 1837, and heard of my use of gallate of silver, and was thus led to adopt what Admiral Smyth then called ‘a quick mode of taking bad pictures’; but, as I told the Admiral in reply, he was born a baby. Whether our philosophical baby is ‘out of its teens’ may be a question; at all events, it is a very fine child, and handles the pencil of nature with consummate skill.