THE HISTORY AND PRACTICE OF THE DAGUERREOTYPE.

Ir is an old adage that "Knowledge is Power." Once perhaps there was a time when its force and truth were dimly perceived-when men in general, while they could not but feel the superiority of individuals among their brethren, did not discover the secret of its source. Now, however, to express such a sentiment is to utter a truism. The saying is so common as almost to require an apology for the repetition of it. Who is there that does not daily hear some illustration of its truth, or have it constantly suggested to his mind in the intercourse of life? Yet, notwithstanding all this, we think it capable of fuller illustration, and worthy of higher appreciation. Every fresh discovery-every step in the progress of science, lends force to the sentiment. Every fresh solution of what heretofore had been a riddle, whether in the study of morals, of the mental powers, or of physics, must inevitably impress our minds with an increasing conviction of the truth of the axiom, "Knowledge is

Power."

Think for a moment of the great agents in nature's operations-light, heat, electricity, chemical affinity, all servants at man's call to do his bidding. Once they were unmanageable, and scared and perplexed him by their doings; but his reason has subdued them, and they are now as tractable as they are mighty and efficient. The stormy winds waft for man food and clothing from every quarter of the globe. The magnetic power, still ungaged, is his unerring pilot across the waste ocean, and bids fair to do more service still. Man yokes light vapour to his car, and rides in triumph behind it. He makes the hot steam to dig up his metal, and fashion it into every form for use and ornament-to spin, to weave, to saw, to grind! Again, not satisfied with supplying his necessities, and even adding to his comforts by means of these grand agents, he must train them to cater to his luxurious tastes. They have builded him a house and furnished it. But he has impressed the spirit of the thunder-cloud into his service, and electricity-yes, the same that makes stout hearts quail beneath the lightning's flash-deigns, under the form of the electrotype, to gild the decorations of his sideboard!

There is one more example of man's triumph yet; it is one of his latest achievements. Hitherto the light of heaven has been proverbially free; it is so no longer. The radiant sunbeam which,

"Glancing o'er the mountain,

Plays in the stream, and dances in the fountain,"

has work to do for him. It has, in less time than we have occupied to write thus far, not only lighted up yonder landscape that we gaze upon with so much pleasure, but has presented us with a beautiful picture of the scene, an unerring delineation of every light and shadow-not a portrait, but an impression, if we may use the term, from the very face of nature itself.

Such is the power presented to our minds by the term "Daguerreotype." In tracing its history, from the first dawning of the art to its present comparatively perfect condition, we are struck with the fact that we can look no further back into the past than the commencement of the present

century. It was not until the year 1802 that the chemical properties of light were made available for the production of pictures or images of objects, and even then to a very slight extent. Sir Humphrey Davy and Mr. Wedgewood discovered a preparation by means of which writingpaper could be rendered sensitive to the action of strong light, thus seeming to tread upon the verge of very important discoveries; but the results of these experiments were so unsatisfactory, both as regarded the quality of the pictures produced and their incapability of resisting the action of light afterwards, that eventually they relinquished the project.

Among the numbers who from this time were employed in investigating the properties of light, Mons. Niepce, a Frenchman, appears to have made the next advance in the photographic art. He commenced his researches about the year 1814, and not until the lapse of thirteen years was he prepared to show any results at all proportioned to the duration and extent of his inquiries, when he forwarded to the Royal Institution of London (1827) a paper upon the subject of his discovery, which he there named "Heliography," signifying drawn by the sun, with some specimens, on metal plates, of the art. He had, previously to this time, accidentally made the acquaintance of a Mons. Daguerre, who was employed in similar investigations, and in the year 1829 they decided to execute a deed of copartnership relating to their past and future discoveries. Still at this time the delineations obtained were exceedingly imperfect. Ten to fourteen hours were necessary for their production, which, from the motion and change of shadows caused by the sun's rays in that time, with other causes, rendered them at best very dubious representations.

Another ten years elapsed, during which time M. Niepce died, and M. Daguerre, still persevering in his efforts, continued to improve the process so greatly that, in the year 1839, the French government, after investigating its merits, secured to him, by legal act, a pension of six thousand francs, and to M. Isidore Niepce, son of the deceased M. Niepce, also a pension of four thousand francs, in consideration of which they were bound to make known to the world the entire process, as well as any future improvements in it which they might at any time make.

It must not be supposed that during all these years English philosophers were paying no attention to the subject of Photography. In the year 1834 a Mr. Talbot was succeeding in the production of some very beautiful pictures upon paper, previously rendered sensitive to luminous influence by means of the nitrate of silver, or common caustic. By the agency of the solar microscope he was enabled to execute, in the full sunshine, these copies of objects in the space of half a second, which process he communicated without reserve to the Royal Society six months before the publication of Daguerre's process in France. He has since patented an improved modification of his discovery, under the name of the "Calotype," which, in point of efficiency, is the nearest in approach to the Daguerreotype of the many and varied processes which have of late been introduced to the world by Sir John Herschell, Mr. Hunt, and others; such, for example, as those termed Cyanotype, Anthotype, Energiatype, &c.

Immediately upon the publication of M. Daguerre's secret in France, whose name henceforth became connected with the art which forms the subject of this paper, the English patent law permitted the right of its exclusive practice to an applicant in this country; and thousands of very beautiful specimens of the art have been executed here, notwithstanding

the enormous price, as compared with the cost, which this monopoly secures to the patentee.

The composition of the plates upon which these pictures are executed is copper plated with silver, in the proportion of about one part of the latter to twenty-five of the former. The quantity of silver used however, varies much with different makers. The plates undergo a careful and longcontinued planishing from the maker's hands, until a true and highly polished surface is obtained. The operator has now to commence a cleaning process, in which the following substances may be used: pure tripoli, fine ground emery, prepared rottenstone; either of which are applied to the plate upon fine cotton-wool, with dilute nitric acid or spirits of wine. To convey an idea of the nicety and cleanliness required in these operations, it may be remarked that, if the slightest grease or dust be present in any of these preparations, or in the cotton-wool, no picture, or an imperfect one, will be obtained, when placed in the camera afterwards. For this reason a piece of cotton-wool once used in rubbing the plate is necessarily thrown aside; for contact either with the fingers or the plate renders it sufficiently soiled to hinder rather than facilitate the progress of the operation. The plate must next be heated over a spirit-lamp to evaporate the mercury used in its composition, again polished with cotton-wool and tripoli, and finally with prepared lampblack upon the velvet buffer. It now possesses the finest surface it is capable of receiving, and is ready for the next stage of the process. This is subjecting it to the vapour of iodine in a closed box for a few minutes, until it has obtained a fine yellow colour, caused by a combination of the iodine and silver, and forming a very thin film of the iodide of silver. The light must be carefully excluded from it during this and all subsequent operations; for a momentary exposure, as will be seen hereafter, would be injurious to the effect. The plate is now in that condition of sensitiveness that any image thrown upon it, by means of a lens or reflector, in a good light, would be permanently received in about five minutes. This, however, in most cases of landscape taking, would be inadequate to fix those transcient and momentary effects of a gleam of sunshine or passing cloud, the faithful delineation of which renders a Daguerreotyped picture peculiarly beautiful and inimitable. It would also interfere considerably with the easy and comfortable position of the sitter, when the art is applied to portraiture; as it must be evident that the slightest motion in any object during the operation of copying, would produce a double image, and of course destroy the truth of the picture. Many attempts have been made to increase the sensitiveness of a plate in the condition just described, viz. that of being simply iodized, and many accelerating substances have been recommended by their respective inventors. That which perhaps is now as much in use as any is a preparation containing bromine in solution, and its application forms the next step in the process. The plate is removed over a cup or glass containing this liquid, where it continues from thirty to fifty seconds, according to the strength of the mixture, which varies by evaporation, and also yields the principle in vapour more rapidly in proportion as the temperature of the surrounding atmosphere is increased. The only accurate mode of testing it is to examine the colour of the plate, which may be done by a hasty glance, with the assistance of reflected light, direct rays being too powerful: when its surface is of a clear rose tint, the operation is complete. Were the plate to be exposed to the vapour either of the iodine or bromine for an indefinite period, the colour would rapidly

century. It was not until the year 1802 that the chemical properties of light were made available for the production of pictures or images of objects, and even then to a very slight extent. Sir Humphrey Davy and Mr. Wedgewood discovered a preparation by means of which writingpaper could be rendered sensitive to the action of strong light, thus seeming to tread upon the verge of very important discoveries; but the results of these experiments were so unsatisfactory, both as regarded the quality of the pictures produced and their incapability of resisting the action of light afterwards, that eventually they relinquished the project.

Among the numbers who from this time were employed in investigating the properties of light, Mons. Niepce, a Frenchman, appears to have made the next advance in the photographic art. He commenced his researches about the year 1814, and not until the lapse of thirteen years was he prepared to show any results at all proportioned to the duration and extent of his inquiries, when he forwarded to the Royal Institution of London (1827) a paper upon the subject of his discovery, which he there named "Heliography," signifying drawn by the sun, with some specimens, on metal plates, of the art. He had, previously to this time, accidentally made the acquaintance of a Mons. Daguerre, who was employed in similar investigations, and in the year 1829 they decided to execute a deed of copartnership relating to their past and future discoveries. Still at this time the delineations obtained were exceedingly imperfect. Ten to fourteen hours were necessary for their production, which, from the motion and change of shadows caused by the sun's rays in that time, with other causes, rendered them at best very dubious representations.

Another ten years elapsed, during which time M. Niepce died, and M. Daguerre, still persevering in his efforts, continued to improve the process so greatly that, in the year 1839, the French government, after investigating its merits, secured to him, by legal act, a pension of six thousand francs, and to M. Isidore Niepce, son of the deceased M. Niepce, also a pension of four thousand francs, in consideration of which they were bound to make known to the world the entire process, as well as any future improvements in it which they might at any time make.

It must not be supposed that during all these years English philosophers were paying no attention to the subject of Photography. In the year 1834 a Mr. Talbot was succeeding in the production of some very beautiful pictures upon paper, previously rendered sensitive to luminous influence by means of the nitrate of silver, or common caustic. By the agency of the solar microscope he was enabled to execute, in the full sunshine, these copies of objects in the space of half a second, which process he communicated without reserve to the Royal Society six months before the publication of Daguerre's process in France. He has since patented an improved modification of his discovery, under the name of the "Calotype," which, in point of efficiency, is the nearest in approach to the Daguerreotype of the many and varied processes which have of late been introduced to the world by Sir John Herschell, Mr. Hunt, and others; such, for example, as those termed Cyanotype, Anthotype, Energiatype, &c.

Immediately upon the publication of M. Daguerre's secret in France, whose name henceforth became connected with the art which forms the subject of this paper, the English patent law permitted the right of its exclusive practice to an applicant in this country; and thousands of very beautiful specimens of the art have been executed here, notwithstanding

the enormous price, as compared with the cost, which this monopoly secures to the patentee.

The composition of the plates upon which these pictures are executed is copper plated with silver, in the proportion of about one part of the latter to twenty-five of the former. The quantity of silver used however, varies much with different makers. The plates undergo a careful and longcontinued planishing from the maker's hands, until a true and highly polished surface is obtained. The operator has now to commence a cleaning process, in which the following substances may be used: pure tripoli, fine ground emery, prepared rottenstone; either of which are applied to the plate upon fine cotton-wool, with dilute nitric acid or spirits of wine. To convey an idea of the nicety and cleanliness required in these operations, it may be remarked that, if the slightest grease or dust be present in any of these preparations, or in the cotton-wool, no picture, or an imperfect one, will be obtained, when placed in the camera afterwards. For this reason a piece of cotton-wool once used in rubbing the plate is necessarily thrown aside; for contact either with the fingers or the plate renders it sufficiently soiled to hinder rather than facilitate the progress of the operation. The plate must next be heated over a spirit-lamp to evaporate the mercury used in its composition, again polished with cotton-wool and tripoli, and finally with prepared lampblack upon the velvet buffer. It now possesses the finest surface it is capable of receiving, and is ready for the next stage of the process. This is subjecting it to the vapour of iodine in a closed box for a few minutes, until it has obtained a fine yellow colour, caused by a combination of the iodine and silver, and forming a very thin film of the iodide of silver. The light must be carefully excluded from it during this and all subsequent operations; for a momentary exposure, as will be seen hereafter, would be injurious to the effect. The plate is now in that condition of sensitiveness that any image thrown upon it, by means of a lens or reflector, in a good light, would be permanently received in about five minutes. This, however, in most cases of landscape taking, would be inadequate to fix those transcient and momentary effects of a gleam of sunshine or passing cloud, the faithful delineation of which renders a Daguerreotyped picture peculiarly beautiful and inimitable. It would also interfere considerably with the easy and comfortable position of the sitter, when the art is applied to portraiture; as it must be evident that the slightest motion in any object during the operation of copying, would produce a double image, and of course destroy the truth of the picture. Many attempts have been made to increase the sensitiveness of a plate in the condition just described, viz. that of being simply iodized, and many accelerating substances have been recommended by their respective inventors. That which perhaps is now as much in use as any is a preparation containing bromine in solution, and its application forms the next step in the process. The plate is removed over a cup or glass containing this liquid, where it continues from thirty to fifty seconds, according to the strength of the mixture, which varies by evaporation, and also yields the principle in vapour more rapidly in proportion as the temperature of the surrounding atmosphere is increased. The only accurate mode of testing it is to examine the colour of the plate, which may be done by a hasty glance, with the assistance of reflected light, direct rays being too powerful: when its surface is of a clear rose tint, the operation is complete. Were the plate to be exposed to the vapour either of the iodine or bromine for an indefinite period, the colour would rapidly