THE 
 
THE 
 
 f^an&»23ooft of f^elfogra#i> ; 
 
 OR, 
 
 THE ART OF WRITING OR DRAWING BY THE 
 EFFECT OF SUN-LIGHT. 
 
 WITH 
 
 THE ART OF DIORAMIC PAINTING, 
 
 AS PRACTISED BY 
 
 M. DAGUERRE. 
 
 " L'aclmirable decouverte dc M. Dagnerrc est un immense 
 service rendu aux arts." — Db la. toe he. 
 
 LONDON : 
 
 ROBERT TYAS, 8, PATERNOSTER ROW. 
 
 MDCCCX.L. 
 
LONDON : 
 
 CLARKE, PRINTERS, SILVER STREET, FALCON SQUARE. 
 
ADVERTISEMENT. 
 
 The following little work has been care- 
 fully compiled from the now numerous 
 treatises on the new and important sci- 
 ence of Heliography. It is hoped that 
 the attempt will not only satisfy a ra- 
 tional curiosity respecting unquestionably 
 the most novel as well as applicable 
 discovery of the present day, but also 
 enable any one of ordinary intelligence 
 to practise the art with little expense 
 and trouble. 
 
CONTENTS. 
 
 PAGE. 
 
 History of Heliography 1 
 
 Nature and Objects of the Science ..... 35 
 
 Materials used in the Art ......... 48 
 
 Directions to prepare Photogenic Paper ... 58 
 
 Cautions for using it 60 
 
 Process of Photogenic Drawing 62 
 
 Preparation of the Plate 63 
 
 Coating the Plate 68 
 
 Taking the Drawing 72 
 
 Disengaging the Coating 78 
 
 Fixing the Sketch 82 
 
 Mr. Talbot's Method : . . . 84 
 
 Directions to obviate defects 86 
 
 Conclusion 90 
 
 Art of Diorama Painting .91 
 
THE 
 
 HISTORY OV THE SCIENCE. 
 
 To whom the honour of discovering this new 
 and important science belongs does not clearly 
 appear. It has been claimed by natives of both 
 France and England, and with such apparent 
 justice that it is difficult to assign the priority to 
 either. Indeed it would seem that the minds of 
 the respective individuals, who put in a plea for 
 reputation on this score, were engaged so much 
 about the same time on the matter, that the 
 three principal candidates appear all equally 
 entitled to it ; the distance from each other 
 being so great that a supposition of collusion 
 
 B 
 
2 
 
 HISTORY OP 
 
 amongst them cannot for a moment be enter- 
 tained. These individuals are MM. Niepce 
 and Daguerre, in France, and a gentleman of 
 the name of Talbot, in England. But, if the 
 latter be indeed entitled to the credit of an in- 
 ventor of this beautiful art, the productions of 
 the former evince so much more proficiency 
 and perfection that we cannot but concede to 
 them the palm of superiority. 
 
 Our own countryman, the celebrated Dr. 
 Ure, author of the Cyclopzedia of Manufactures, 
 in his excellent but frequently unjustly abused 
 work on geology, published some years since, 
 laid down in an admirable but apparently too 
 abstruse chapter on light, which he prefixed to 
 the body of his work, the law of the effects of 
 coinciding rays, and clearly showed, by an ex- 
 periment familiar to the comprehension of all, 
 and easily made by any one, that its effect js 
 to produce darkness, just as certainly, and just 
 as palpably, as the effect of parallel rays from 
 the sun is to produce light. But he was not 
 
THE SCIENCE. 
 
 3 
 
 probably aware at the time that the darkness re- 
 sulting from coincident rays was not only a 
 mechanical consequence, if we may so speak, 
 but that rays of light possessed and evinced a 
 chemical property — that of rendering the dark- 
 ness permanent upon any substance which was 
 fitted to receive and competent to retain it. 
 We do not say that the doctor was the first to 
 discover the faculty of light of which he speaks, 
 but he was the first to make it popularly, and, 
 therefore, generally known, and too much praise 
 cannot be ascribed for the singular perspicuity 
 by which he has made it evident. 
 
 Giovanni Baptiste Porta, a Neapolitan phy- 
 sician, about two centuries since, discovered that, 
 if light were admitted through a small circular 
 aperture into a closely shut room, all the objects 
 without from which reflected rays reached the 
 hole would be painted on the opposite wall, in 
 strength and size according to their distance, 
 with their forms and relative situations, as in an 
 extended picture, with the most precise exact- 
 
4 
 
 HISTORY OF 
 
 ness. He subsequently found that the hole need 
 not be very small, but that in fact it might be 
 of any size, if covered with a lens. This was, 
 however, only doubling the contrivance ; for the 
 increased quantity of light, which the larger hole 
 afforded, was of course condensed by the cen- 
 tralizing power of the lens. But the images 
 produced by these simple means were faint and 
 somewhat confused, while those effected by aid 
 of the lens were proportion ably intense and pro- 
 perly defined. This plainness became remark- 
 ably increased after the discovery of the achro- 
 matic lens ; and, still more, when subsequently 
 the periscopic lens was applied, the additional 
 force of the effect in consequence of its focal- 
 izing power was truly astonishing. 
 
 Porta had several dark chambers constructed 
 of a cylindrical form of any particular lengthy 
 with a lens at one end and a white card or paper 
 at the other, so placed as to be within the focus 
 of the glass upon which the external images 
 were depicted. This plan he intended for such 
 
THE SCIENCE. 
 
 5 
 
 persons as knew not how to draw ; so that we 
 have here the almost perfect design of the 
 instrument of Daguerre. 
 
 He conceived that to obtain perfect represen- 
 tations of the most complicated sets of objects, 
 it was only necessary to follow the focal light, 
 with the trace of a crayon. In this idea, how- 
 ever, he was not precisely correct ; for painters 
 and designers, especially those who were engaged 
 on large works, such as panoramas and dioramas, 
 and who used the dark chamber, found that it 
 was only useful for denning objects in the mass, 
 to give them the respective sizes and positions 
 according to the rules of linear perspective; but 
 to the effects of what is called aerial perspec- 
 tive they found the dark chamber completely 
 incompetent. Nor could their utmost efforts 
 avail them ta any requisite extent, or render 
 what they did accomplish of permanent use. 
 This object, however, has at length been 
 attained, and he who, perfectly ignorant of 
 the art of drawing, is destined to wander to the 
 b3 
 
6 
 
 HISTORY OF 
 
 remotest corners of the earth, may now, without 
 the aid of an artist, carry with him the true and 
 faithful delineation of the home of his youth, 
 and of the objects most dear in his earliest recol- 
 lections, with a truth and fidelity that no manual 
 operation could imitate. 
 
 Alchemists, in those fruitless attempts after 
 the elixir vita, and the transmuting stone, which 
 formed the foundation of the present invaluable 
 science of chemistry, succeeded in uniting silver 
 with a marine salt, and produced a combination 
 called lune or advent come. In the work of 
 Fabricius, Be reous metallicis, published in 
 1566, a substance of this kind is especially 
 noticed. It had the colour and transparency of 
 horn, and the fusibility and softness of wax, 
 but, if exposed to the light, changed nearly to 
 violet, and by the continued action of the same 
 influence, became nearly black. This was the 
 natural argent come, or lunar caustic. 
 
 The salt produced by the alchemists possessed 
 the remarkable property of turning blacky and 
 
THE SCIENCE. 
 
 1 
 
 the blackness was vivid just in proportion as the 
 rays which occasioned it were powerful. Cover 
 a sheet of paper with a coating of argent come, 
 or, as it is now called, chloride of silver. Obtain 
 by the aid of the lens the form of some object 
 upon this coating, and the parts occupied by the 
 figure will change to a dark colour, while the 
 remainder of the paper, or rather its coating, will 
 continue white. The parts which have a strong 
 cast of light upon them will become quite black, 
 the half tints and shades being formed by grey, 
 through a less forcible luminence. 
 
 Place an engraving upon the paper covered 
 with chloride of silver, and expose it altogether 
 to the suns rays, the engraving being upper- 
 most, and that part of the paper covered by the 
 engraving will remain white, in consequence of 
 the interception of the rays, which cannot, on 
 that account, reach the coating of chloride ; while 
 all the rest will be tinged with black. Where 
 the paper on which the engraving is printed 
 has retained its semi-transparency, the saline 
 
8 
 
 HISTOity OF 
 
 coat will be obscured accordingly ; the result 
 being that the coating on which the operation 
 creates its effect will have its forms and shades 
 in an inverse manner ; the darkest parts of the 
 engraving being whitest on the chloride, and the 
 lightest parts of the print the darkest on the 
 paper. 
 
 It might have been supposed that in the pos- 
 session of so complete a knowledge of the. effects 
 of light upon this chloride, the alchemists would 
 in the course of time have earned it out to some 
 real practical purpose. But the minds of those 
 men were too abstract, were too much occupied 
 in the absorbing pursuit of the high, and, to 
 them, incomparably more interesting and im- 
 portant design of realizing a most facinating 
 though visionary object. They thought that if 
 they could attain this great good, all other bene- 
 fits would naturally follow ; and, if their premises 
 had been correct, their conclusion would have 
 been both wise and sound. They were lifted 
 above all the considerations of ordinary life and 
 common objects, and it therefore remained for 
 
THE SCIENCE. 
 
 9 
 
 the nineteenth century to conceive and accom- 
 plish the photogenic art. 
 
 M. Charles, a Frenchman, succeeded in ob- 
 taining silhouettes, or black profile portraits, 
 but he never made known the nature or steps of 
 his process, and his secret died with him. The 
 first authentic intimation of this new art was con- 
 tained in a memoir of Mr. Wedgwood, the cele- 
 brated improver of the manufacture of porce- 
 lain in this country, whose paper appeared in the 
 June number of the Journal of the Royal In- 
 stitution in 1802. The author was desirous of 
 obtaining by the assistance of paper, prepared 
 with chloride or nitrate of silver, the representa- 
 tions of church windows, as well as of engravings, 
 for his pottery ; and, though he appears to have 
 adopted a very close approximation to the present 
 practice, he failed in his chief design. He says, 
 " the images formed by means of a camera ob- 
 scura have been found to be too faint to produce, 
 in any moderate time, an effect upon the nitrate 
 of silver." 
 
 Wedgwoods celebrated commentator, the il- 
 
10 
 
 HISTORY OF 
 
 lustrious Sir Humphry Davy, did not contra- 
 dict the assertion relative to the camera obscura. 
 He added that he attempted to copy very small 
 objects by a solar microscope, but only at a very 
 short distance from the lens. Neither Wedg- 
 wood nor Sir H. Davy discovered an expedient 
 for preventing the borders of their drawings from 
 turning black. Their copies in consequence 
 never could be examined in broad daylight, for, 
 as soon as they were exposed to its strength of 
 action, the whole of the paper began to assume 
 one uniformly dark tinge. 
 
 After these imperfect and insignificant results, 
 nothing was attempted until the researches of 
 MM. Niepce and Daguerre. The former of these 
 two gentlemen was a retired man of business in 
 the neighbourhood of Chalons-sur-Saone, who 
 devoted his leisure to scientific inquiries, and his 
 first experiments in photography, or making per- 
 manent marks by the aid of light, appear to have 
 been made as early as 1814; but his first con- 
 nection with M. Daguerre took place in the 
 
THE SCIENCE. 
 
 11 
 
 month of January, 1826. Through the indis- 
 cretion of an optician at Paris, he became ap- 
 prised that M. Daguerre was endeavouring 
 to accomplish the same object as that to 
 which he had devoted his attention; having 
 only to fix the images of his design in the dark 
 chamber to make his plan perfect. These 
 facts are verified by letters, still in existence, 
 which attest that the earliest works of M. Da- 
 guerre were effected in 1826. 
 
 In 1827, M. Niepce came to England, and 
 in December of the same year he presented a 
 memoir upon this subject to the Royal Society 
 of London. His paper was accompanied by 
 many illustrations upon metal produced by the 
 methods which he had discovered. These illus- 
 trations, which are still in good condition, 
 might be gathered from the several scientific 
 collections of distinguished Englishmen, and 
 prove, without the possibility of contradic- 
 tion, that engravings could be copied, and were 
 so, by means of photography, in 1827. They 
 
12 
 
 HISTORY OF 
 
 present the appearance of advanced sketches 
 produced by means of a graver. M. Niepce 
 knew, in 1827, how to make shades correspond 
 to shades, half-tints to half-tints, and lights to 
 lights ; and, above all, he knew, when he had 
 accomplished his object of copying an engrav- 
 ing, how to make that copy insensible to the 
 subsequent and blackening rays of the sun ; 
 thus resolving, as his self-lauding country- 
 men phrase it, a problem which had defied the 
 sagacity of Wedgwood and the genius of Davy. 
 
 The registered deed of partnership between 
 MM. Niepce and Daguerre is dated 14th 
 December, 1829 ; and they thenceforward pro- 
 secuted their photographic inquiries together. 
 Subsequently, the son of M. Niepce took the 
 place of his father in the engagement. In the 
 body of this document, the several portions of 
 the discovery are accorded to the respective 
 parties to the contract, and it contains the re- 
 markable assertion that the discovery of M. 
 Daguerre had elicited a process which " repro- 
 
THE SCIENCE. 
 
 ra 
 
 duced images with sixty or eighty times the 
 force of the previous plan." 
 
 In speaking all along as we have done of 
 the proceedings of M. Niepce, it is particularly 
 necessary to observe the words of the contract, 
 "pour la copie photo graphique des gravures"— 
 the photographic copy of engravings; for, after a 
 number of fruitless essays, M. Niepce had nearly 
 renounced the attempt of producing images from 
 nature. He could not create a design. He 
 could copy engravings, but he could not transfer 
 the images of natural objects. The preparations 
 of which he made use failed to render the dark 
 marks sufficiently strong under the influence of 
 the light. He succeeded in giving parts of a 
 scene or of a landscape with sufficient power, 
 but there was nothing complete. Here and 
 there every thing was boldly portrayed, but in 
 other places there was a poor and insufficient 
 representation ; and, between, were places, com- 
 paratively of considerable size, exhibiting gaps 
 which entirely destroyed the effect or rather the 
 c 
 
14 
 
 HISTORY OF 
 
 appearance of a picture. On the other hand, 
 we ought to give an enumeration of the disco- 
 veries which after many minute and painful 
 and varied efforts M. Daguerre had made. 
 
 M. Niepce dissolved some dry bitumen of 
 Judea in oil of lavender, and, after evaporation, 
 the remainder was a thick varnish, which he 
 spread upon a polished metallic plate, as, for 
 instance, of plated copper, or upon a plate of 
 silver. The plate, after being submitted to a 
 gentle heat, remained covered with a white and 
 adhering powder, which was bitumen in powder. 
 The plate, thus prepared, was placed upon the 
 hearth of the camera obscura. After a certain 
 time, the feeble lineaments of an image might 
 be perceived. M. Niepce ingeniously conceived 
 that these traits, so little perceptible, might be 
 materially strengthened. In fact, after plunging 
 the plate into a mixture of oil of lavender and 
 rock oil, he observed that the portions of the 
 covered plate which had been exposed to the light 
 remained nearly untouched, while, on the others 
 
THE SCIENCE. 
 
 15 
 
 the covering rapidly dissolved and left the plate 
 almost naked. After having washed the plate 
 with water, he had the image formed in the 
 camera obscura, the lights corresponding to the 
 lights, and the shades to the shades. The lights 
 were formed by the diffused light proceeding 
 from the whitened matter and not cleared from 
 the bitumen ; the shades, by the parts po- 
 lished and become denuded, which was, it 
 should be observed, so skilfully managed that 
 parts of the sombre objects reflected them- 
 selves in a glass ; provided also, that they 
 were placed in such a position that they were 
 not directly opposite to the mirror, but aslant, 
 with an oblique aspect and a faint light upon 
 them. The half tints, where they were percep- 
 tible, or existed at all, resulted from that part 
 of the varnish where a partial penetration of 
 the dissolvent had rendered it less solid than 
 those parts which were untouched. 
 
 The bitumen of Judea, reduced to an impal- 
 pable powder, had no clear whiteness about it : it 
 
16 
 
 HISTORY OF 
 
 would indeed be almost exceeding the truth to 
 call it grey. Contrast between the lights and 
 shades of these designs of M. Niepce's was con- 
 sequently far too weak for the desired, and, we 
 ought to say, necessary effect ; and, to increase 
 it, he thought of strengthening the blacks in the 
 plate by an after-influence, obtained either by 
 sulphuret of potash or iodine. But he does not 
 appear to have known that the latter of these 
 two substances, when exposed to the light of day, 
 would have been subject to continual change. 
 He could not pretend to preserve so sensitive a 
 thing as iodine ; he only wished to apply it to 
 the surface of the blackening substance, and 
 that, too, after the formation of the image in the 
 dark chamber. In such an operation what would 
 have become of the half tints ! 
 
 To the number of these great inconveniences 
 of the method of Niepce's should be added the 
 circumstance that, if the dissolvent were too 
 strong, it would sometimes raise the varnish in 
 places ; after a little, indeed, entirely ; if too 
 
THE SCIENCE. 
 
 17 
 
 weak, it would not sufficiently disengage it from 
 the image. Success was never certain. 
 
 M. Daguerre conceived a method which he 
 called Niepce's plan completed. He at first 
 substituted the residuum of the distillation of oil 
 of lavender in bitumen, on account of its greater 
 whiteness and sensibility. That residuum was 
 dissolved in alcohol, or in ether, and the liquid 
 was deposited in a very thin layer upon the 
 metal laid horizontally, and prepared to receive 
 it ; and it left, in evaporation, a uniform pulve- 
 rulent covering, a result which was not ob- 
 tained by the process of Niepce. 
 
 After the exposure of the plate, thus prepared, 
 to the heat, and in the dark chamber, M. Da- 
 guerre placed it horizontally, and at a distance, 
 above a vessel containing essential oil at the 
 ordinary temperature. The vapour proceeding 
 from the oil left the particles of the pulverulent 
 plaster which had experienced the action of the 
 strong light untouched. It penetrated partially, 
 and more or less, the portions of the same covering 
 c 3 
 
L8 
 
 HISTORY 0£ 
 
 which in the dark chamber corresponded to the 
 dark tints. The parts remaining in shade were 
 penetrated entirely. Here the metal did not 
 show naked in any part of the design ; but the 
 lights were formed by the agglomeration of a 
 multitude of white and macerated particles ; the 
 half tints by particles equally condensed, but in 
 which the vapour had more or less weakened the 
 whiteness and destroyed the closeness; the 
 shades by particles always in the same number, 
 but become entirely transparent. 
 
 More of effect, a greater variety of tones, 
 more regularity, certainty of success in the pro- 
 cess, as well as of avoiding carrying away any 
 portion of the image, were the advantages of 
 M. Daguerre's modified method. Unfortunately 
 the oil of lavender, which is more sensible to the 
 action of light than the bitumen of Judea, is yet 
 so slothful in its action that the design does not 
 begin to form until after a very long time. 
 
 The kind of modification which the residuum 
 of the oil of lavender receives by the action of 
 light, and in consequence of which the vapour 
 
THE SCIENCE. 
 
 19 
 
 of the essential oil penetrates its substance with 
 more or less facility, is still unknown to us. 
 Perhaps we should regard it as a simple detach- 
 ment of particles, perhaps as a new arrangement 
 of molecules of the matter. This double hypo- 
 thesis would explain how the modification is 
 gradually weakened and at length disappears. 
 
 Through a long course of observation Da- 
 guerre saw the reasons of his repeated failures, 
 and, by indomitable perseverance and the exer- 
 cise of ingenuity, he at length so far overcame 
 them as to bring his invention to a practical state. 
 
 He put upon the surface of a metallic plate, 
 the tablet which receives the images, a coat of gold 
 yellow, and then, turning it downwards, placed 
 it horizontally in a box at the bottom of which 
 there was a little iodine undergoing spontaneous 
 evaporation. When this plate comes out of the 
 dark chamber, not a trace can be seen upon it. 
 The yellow coat of the iodine of silver, which, 
 has received the impress of the figure, is one 
 uniform dark shade without any mark. 
 
 Next, the plate is exposed, in a second box, to 
 
20 
 
 HISTORY OF 
 
 an ascending mercurial vapour which raises a 
 capsule, when the liquid is coming upwards, by 
 the action of a spirit lamp, and this vapour im- 
 mediately produces a most curious effect. It 
 becomes attached in abundance to the parts 
 of the surface of the plate which have been ex- 
 posed to a strong light, while those parts which 
 have been left in the shade remain untouched ; 
 at length it begins to work upon the space occu- 
 pied by the half tints, and in a greater or less de- 
 gree makes its impression upon the plate, and ac- 
 cording to the intensity of the light on the precise 
 spot makes it either more or less dark. When 
 the feeble light of a candle is used, the operator 
 can follow the gradual formation of the image 
 step by step. He will be able to perceive the 
 mercurial vapour, like a delicate graver, mark 
 each part of the plate with the proportionate 
 depth. 
 
 The image being thus produced in the 
 camera, what should hinder its alteration when 
 exposed to the light of day was a question that 
 
THE SCIENCE. 
 
 21 
 
 very naturally proposed itself to the mind of the 
 inventor. This he accomplished hy immersing 
 the plate upon which the design had heen ef- 
 fected in hyposulphate of soda, and afterwards 
 washing it with hot distilled water. 
 
 M. Daguerre says that the image is obtained 
 better on a surface of plated metal, i.e., upon a 
 plate of copper covered with silver, than upon 
 one of silver alone. Should such be the case, it 
 seems to prove that electricity plays a consi- 
 derable part in the operation. 
 
 The plate should be first rubbed with pumice 
 stone, and then cleaned with nitric acid diluted 
 with sixteen parts of distilled water. The in- 
 fluence which the acid exercises in this part of 
 the process is both singular and useful : it raises 
 little molecules of copper on the surface of the 
 silver. 
 
 Although the thickness of the slight coat of 
 iodine, as the several considerations of M. Du- 
 mas show, would not be more than the mil- 
 lionth part of a millemetre, it is necessary for 
 
22 
 
 HISTORY OF 
 
 the due proportion of light and shade that it 
 should he perfectly even in every part. He pre- 
 vented a greater deposit of the iodine upon the 
 borders than upon the centre of the plate, by 
 putting round it a slight frame of the same 
 metal, which he affixes by nails to the tablet of 
 wood which bears the whole. But as yet we 
 are unable to explain the mode of physical 
 action of that plate satisfactorily. 
 
 There is another circumstance not less mys- 
 terious. If it be desired that the image should 
 produce the maximum of effect in the ordinary 
 vertical position of the tables, it is necessary that 
 the plate should be placed at an angle of 45 deg. 
 to the ascending vapour. If the plate is horizontal 
 at the moment of the precipitation of the mer- 
 cury, it would be necessary, on the formation 
 of the image, to look at it in an angle of 45 deg, 
 in order to obtain the best view of the represen- 
 tation. 
 
 In attempting to explain the singular process 
 of M. Daguerre, the idea is immediately pre- 
 
THE SCIENCE. 
 
 23 
 
 sen ted to the mind that light in the camera 
 occasions the vaporization of the iodine, 
 wherever it has come in contact with the gilt 
 plate ; that the metal becomes denuded, and that 
 the mercurial vapour acts freely on the naked 
 metal, during the second operation, and produces 
 a white and pasty amalgam ; that the washing 
 of the hyposulphate is intended to raise the parts 
 of the iodine which the light has not disengaged, 
 and, speaking artistically, to make those parts 
 of the plate bare which should produce the 
 shadows. 
 
 The plate is not apparently increased in 
 weight by the yellow covering of iodine, while, on 
 the contrary, it is so, very perceptibly, under the 
 action of the mercurial vapour. M. Pelouze, 
 an ingenious Frenchman, who has taken con- 
 siderable pains in this invention, asserts that, 
 notwithstanding the presence of a little of the 
 amalgam on the surface, the plate weighs less 
 after the operation than it did before. It would 
 consequently appear that the hyposulphate dis- 
 
24 
 
 HISTORY 01 
 
 perses part of the silver, and a chemical 
 examination confirms the correctness of the 
 supposition. 
 
 To assign a reason for the effect of light on 
 the designs which M. Daguerre submitted to its 
 effects, it seems sufficient to admit that the plate 
 of silver becomes covered, during the operation 
 of the mercurial vapour, with spherules of 
 the amalgam ; that these spherules, very close in 
 the lights, gradually diminish in the half tints 
 towards the dark parts, where there ought not to 
 be any. 
 
 The supposition of the philosopher has proved 
 correct. M. Dumas discovered, by the micro- 
 scope, that the light and half tints are really 
 formed by spherules, the diameter of which 
 appeared to him, as well as to M. Adolphe Brog- 
 niart, to be almost invariably about the eight- 
 hundredth of a millemetre, but still the neces- 
 sity of presenting the plate on the precipitation 
 of the mercurial vapour at a dip of 45 deg. 
 remains to be accounted for. It has been ratio- 
 
THE SCIENCE. 
 
 25 
 
 nally supposed, that is, conceiving this inclination 
 to be indispensable, to indicate the presence of 
 points or prisms of crystallization, which so- 
 lidify and group themselves vertically in a com- 
 plete or semi-liquid, and thus have an inclina- 
 tion relative to the position of the plate to such 
 an extent as renders that inclination of the plate 
 necessary. 
 
 Our uncertainty respecting this matter only 
 shows how far as yet we are from understanding 
 the mode of action and the nature of this beau- 
 tiful and highly important instrument of art. 
 
 We have thought it better to follow the in- 
 vention from its rise through the several stages of 
 its practical process, in order to make the reader 
 clearly acquainted with the nature of the sci- 
 ence, or, at least, as clearly as established facts 
 can exhibit it. The matter itself was of such 
 a curious and recondite character that few 
 had ever imagined its existence. Oil this side 
 of the Channel there was but one person who ap- 
 pears to have had any correct apprehension of 
 
 D 
 
26 
 
 HISTORY OF 
 
 the action of light, and the results which he 
 obtained were so faulty and incomplete that they 
 were not to be compared with the draughts of 
 the French artists. 
 
 Mr, Talbot had submitted a description of 
 his operation to the Royal Society of London, 
 of which he is a fellow, some short time previous 
 to the art of Heliography being publicly talked 
 of in France, and he has given good evidence to 
 show that he had been acquainted with the prin- 
 ciples for nine or ten years before. Some at- 
 tempt has also been made by the Americans to 
 arrogate the honour of the discovery to them- 
 selves, but these were but coldly received, and 
 have at length, apparently, altogether died away. 
 Mr. Talbot, with a generosity that does him 
 high honour, exposed the whole of his plan to 
 the public, and explained every part of it, so 
 sufficiently, indeed, as to enable Messrs. Acker- 
 mann, of the Strand, to fit up boxes whereby any 
 person of only common intelligence might make 
 photogenic drawings for himself. 
 
THE SCIENCE. 
 
 27 
 
 M. Daguerre, in the meantime, had submitted 
 his designs and explanations to the Chamber of 
 Deputies, with a view to obtain from the French 
 Government a compensation for making the 
 whole process of his invention public, in order 
 to render it of general and immediate utility, 
 and a commission was appointed to examine the 
 project of law for this purpose. After sufficient 
 inquiry, a report was made to the Chamber 
 of Deputies by the celebrated philosopher M. 
 Arago, and another to the House of Peers 
 by M. Gay-Lussac ; by which it appears that, 
 after having had every opportunity of testing 
 the certainty of the process, they were con- 
 vinced of its capability to effect that which the 
 inventor said it would accomplish. During 
 the inquiry, M. Daguerre operated in the pre- 
 sence of one of the members of the commission, 
 and made that gentleman as well acquainted 
 with it as himself. In consequence of their re- 
 ports a resolution was passed granting to M. 
 Daguerre a pension of 6,000 francs per annum, 
 
28 
 
 HISTORY OF 
 
 for life, and another of 4,000 francs to the son of 
 M. Niepce, who had been joined with M. Da- 
 guerre in the attempt to bring the invention to 
 a satisfactory issue since 1829, he having at that 
 period taken his father's interest in the affair. 
 The pension to M. Daguerre was afterwards 
 increased to 10,000 francs, and the law received 
 the royal assent on the 15th of June, last year. 
 
 How far M. Daguerre might have gone on 
 in the improvement of his plan it is impossible 
 to say, for, when on the high tide of successful 
 operation, his diorama, with the whole of his 
 plans and means of operating, were unfortu- 
 nately reduced to ashes by an accidental fire. 
 But he has already a very eminent degree of 
 success, and not only himself produced sur- 
 prising results, but by his proceedings has 
 called the attention of many able and scientific 
 men to the subject, and thereby insured the cer- 
 tainty of progressive improvement. 
 
 It remains perhaps that we should say some 
 little of the inventor of photogenic drawing. 
 M. Daguerre, then, is an artist of considerable 
 
THE SCIENCE. 
 
 29 
 
 celebrity as a painter, and has long been an 
 esteemed member of the French Academy of 
 Fine Arts, and of the Academy of St. Luke, as 
 well as of other institutions of a similar cha- 
 racter in his own country, and stood high in 
 France long before his discovery of the science 
 of which we treat extended his reputation be- 
 yond the bounds of France. He is much re- 
 garded for his natural goodness as well as his 
 artistical powers, especially for that surest indi- 
 cation of true genius, modesty. 
 
 When, on the 19th of August, 1839, in ac- 
 cordance with his agreement with the Chambers 
 of Legislature, the discovery was to be made 
 known, no inducements could prompt him to 
 make his own explanations; and M. Arago, of 
 whom we have spoken above, as being one of 
 the reporters on the commission, was obliged to 
 undertake the task of making the public ac- 
 quainted with the secret of the process. In 
 stating these circumstances to the assembly 
 who attended on the occasion, this great man, 
 i> 3 
 
30 
 
 HISTORY OF 
 
 as all Europe acknowledges him to be, with a 
 feeling that does him infinite honour, after re- 
 porting his endeavours to induce M. Daguerre 
 to appear in that place, said, u a little too much 
 modesty, a burden which is generally so lightly 
 borne, suggested obstacles which I was not so 
 happy as to surmount." His substitute, however, 
 as might have been expected, proved satisfac- 
 torily competent to the task he had undertaken. 
 
 As it may be interesting to our readers, and 
 will serve to complete this hasty sketch of 
 Heliography, we subjoin the royal ordinance to 
 the Chambers, which runs as follows ; — 
 
 " Louis Philippe, King of the French, to all to 
 whom these presents shall come. 
 
 We have ordered, and do order, that the bill 
 which shall be presented to the Chamber of 
 Deputies by our Minister, Secretary of State for 
 the Interior, in our name, be explained by him 
 and supported in the discussion. 
 
 Art. I. The agreement concluded on the 
 14th June, 1839, between the Minister of the 
 
THE SCIENCE. 31 
 
 Interior, acting in behalf of the State and MM. 
 Daguerre and Niepce, jun., is added to the 
 present law, and approved. 
 
 Art. II. There is granted to M. Daguerre 
 an annual pension, for life, of 6,000 francs, and 
 to M. Neipce, jun., an annual pension, for life, 
 of 4,000 francs. 
 
 Art. III. These pensions shall be entered in 
 the book of civil pensions of the public Treasury, 
 with an enjoinment that they shall be published 
 with the present law. They shall not be sub- 
 ject to the prohibitive laws of accumulation. 
 Reversions of one half shall be settled on the 
 widows of MM. Daguerre and Niepce. 
 
 Given at our palace of Tuileries, on the 
 15th J une, 1839. 
 
 Signed. Louis Philippe. 
 Witnessed, Deuchatel." 
 
 In compliance with this ordinance, a law was 
 passed, founded upon and embracing the follow- 
 ing agreement. 
 
 " Between the undersigned, M. Deuchatel 
 
32 
 
 HISTORY OF 
 
 Minister, Secretary of State for the Department 
 of the Interior, on the one part, and MM. 
 Daguerre, (Louis Jacques Mand£), and Niepce 
 jun., (Joseph Isidore), on the other part, the 
 following has been agreed upon. 
 
 Art. I. MM. Daguerre and Niepce, jun., 
 have ceded to M., the Minister of the Interior, 
 acting on behalf of the State, the process of 
 M. Niepce, sen., with the improvements of 
 M. Daguerre, and the later process of M. Da- 
 guerre, for fixing the images of the camera 
 obscura. They engage to deposit in the hands 
 of M., the Minister of the Interior, a sealed 
 packet containing the history and exact and com- 
 plete description of the said processes. 
 
 Art. II. M. Arago, Member of the Chamber 
 of Deputies, and of the Academy of Sciences, 
 who has taken a knowledge of the said processes, 
 has verified beforehand all the portions of the 
 said processes, and has testified to the correct- 
 ness of the representations. 
 
 Art. III. The packet shall be opened, and 
 
THE SCIENCE. 
 
 33 
 
 the description of the processes published, after 
 the adoption of the Bill, which is spoken of 
 above. M. Daguerre will then, if it is required 
 of him, operate in the presence of a commission 
 named by the Minister of the Interior. 
 
 Art. IV. M. Daguerre engages, besides, to 
 give a description of the peculiarities which 
 distinguish his painting of the diorama. 
 
 Art V. He shall be bound to make known 
 all the improvements which he shall make, from 
 time to time, in any or all of these inventions. 
 
 Art. VI. As the price of these concessions 
 the Minister of the Interior engages to require 
 of the Chambers, for M. Daguerre, who accepts 
 it, an annual pension of 6,000 francs for life, and 
 for M. Niepce, who agrees also to accept it, an 
 annual pension of 4,000 francs for life. 
 
 These pensions shall be entered in the Civil 
 Pension Book of the Treasury. They are not to 
 be subject to the laws which prohibit accumula- 
 tions; and a reversion of a moiety of each pension, 
 respectively, is settled upon their several widows 
 
34 
 
 HISTORY OF THE SCIENCE. 
 
 Art. VI I. In the event of the Chambers not 
 adopting, during the present session, this project 
 of law granting these pensions, this agreement 
 shall be null and void, and MM. Niepce and 
 Daguerre, shall have their packet returned to 
 them unopened. 
 
 Art. VIII. The present agreement shall be 
 registered on payment of one franc. 
 
 Made triple at Paris, 14th June, 1839. 
 
 Signed by M. Deuchatel, M. Daguerre, and 
 M. Niepce. 
 
 An exact copy of the original has been an- 
 nexed to the project of law. 
 
 Signed. Deuchatel. 
 Secretary of State for the Interior." 
 
35 
 
 NATURE AND OBJECTS OE THE SCIENCE. 
 
 The several names which this new science has 
 received are so correctly indicative of its nature 
 that they may be said to be definitions of it. 
 It was first called photography, from two Greek 
 words, signifying, writing by light ; it was then 
 called the art of photogenic draiving, or drawing 
 produced or occasioned by light ; and, at length, 
 M. Daguerre gave it the equally expressive, 
 though not more appropriate, name of Hello- 
 graphy, or, writing by the sun; the two last 
 appellations, like the first, being derivatives from 
 the Greek. 
 
 An idea had long been entertained that there 
 was some method by which the fleeting repre- 
 sentations of outward objects might be retained 
 and made steadfast, but it seemed too flimsy to be 
 held by a rational philosopher. The researches 
 of late years into the chemical combinations 
 
36 
 
 NATURE AND OBJECTS 
 
 of light, however, and the observation of its 
 effects upon the colours of natural objects, had 
 confirmed the notion that there was a possibility 
 of fixing its impress, and it was known that 
 wherever light had fallen upon the substance 
 designated nitrate of silver, or upon any thing 
 rubbed over by it, a black mark was left. 
 
 The object of this science, then, is to fix the 
 figures and colours of objects upon a prepared 
 surface by the reflection of light alone. By the 
 well known and beautiful invention, the camera 
 obscura, the appearance of objects external to 
 the box or place which contains the apparatus 
 is beautifully exhibited on an horizontal plane, 
 in their just proportions, colours, and perspec- 
 tive. Every portion of the scene, however mi- 
 nute or obscure, is faithfully depicted and re- 
 tained as long as the observer may choose. 
 Here then was a means by which the representa- 
 tion was secured for any desirable length of 
 time, so that if there was a power in light to 
 leave the trace of the physical things which it 
 
OF THE SCIENCE. 
 
 37 
 
 clad in beauty, it might by this means be se- 
 cured. The substitution of a substance which, 
 when submitted to the action of light, retained 
 its impress, for the plain glass of the camera, 
 sufficed to accomplish the purpose of a retention 
 of the image depicted. 
 
 But something more than this was required, for 
 either the drawing must be kept in the dark, or 
 the whole of the surface prepared would, on ex- 
 posure to open daylight, equally partake of the 
 same dark hue. Instead of exhibiting all those 
 objects of every form, variety, and character, of 
 which the human mind is cognizant, by the 
 tracing of characters upon the black paper, it 
 would be smearing the whole surface with one 
 unseemly blotch. The means, however, adopted 
 by Daguerre, for securing the permanency of the 
 marks, prevented this fatal fault, and rendered 
 the science truly what it is called, Heliography. 
 Such is the simple nature of one of those 
 important discoveries which are occasionally 
 promulgated to the world. The full power and 
 
 E 
 
38 
 
 NATURE AND OBJECTS 
 
 utility of the science of Heliography may not 
 be developed until the present generation has 
 passed to their last resting places, and a longer 
 period will assuredly elapse before its universal 
 adaptation to the several purposes for which 
 it is fitted. 
 
 But of its capacity for service, no small pros- 
 pect may now be obtained, and it appears to 
 have been well appreciated by the enlightened 
 individuals who constituted the commission of 
 the French legislative chambers. Their thoughts 
 are so happily expressed that we cannot do 
 better than transcribe them, especially as the 
 important matters to which they refer are 
 such apt illustrations of the benefits of the 
 science that better could hardly have been se- 
 lected. 
 
 " Your Commission have made the necessary 
 dispositions for the day of discussion of the law 
 (of granting a pension to the inventors), for all 
 the members of the Chamber, if they think con- 
 venient, may appreciate the results of the Da- 
 
OF THE SCIENCE. 
 
 39 
 
 guerrotype, and form for themselves a notion of 
 the utility of such an apparatus. Every one 
 will be able, upon an examination of many of the 
 pictures which will pass under your eyes, to judge 
 of the immense advantages which would have 
 been derived during the expedition in Egypt, 
 from so prompt a means of drawing such exact 
 representations; and each will be struck by 
 the reflection that, if photography had been 
 known in 1798, we should to-day have pos- 
 sessed faithful depictions of a good number of 
 those emblematic pictures of which the cupidity 
 of the Arabs and the Vandalism of others have 
 deprived the world. 
 
 " To copy the millions upon millions of 
 hieroglyphics which cover even the exterior of the 
 great monuments of Thebes and Memphis, of 
 Carnac, &c, would require scores of years, and 
 legions of designers. By the assistance of the 
 Daguerrotype a single man could finish that im- 
 mense work. Supply the institute of Egypt 
 with two or three of the apparatus of M. Da- 
 
40 
 
 NATURE AND OBJECTS 
 
 guerre, and upon most of the great plates in that 
 celebrated work ( the fruit of our immortal expe- 
 dition) of the vast extent of real hieroglyphics, 
 these instruments would replace these fictitious 
 or invented representations; and the designs 
 would surpass, above all conception, in fidelity, 
 and peculiarity of tint, the works of our most 
 able painters. The photographic images, being 
 subject in their formation to the rules of 
 geometry, would through the aid of a small 
 number of data admit of coming at the exact 
 dimensions of the most elevated and inaccessible 
 parts of those edifices. 
 
 u These reminiscences in which the savans 
 and artists, so zealous and celebrated, who 
 were attached to the army of the east, could 
 not, without strange mistake, find the shadow of 
 blame, will without doubt recall the thoughts to 
 the works which are at present executed in our 
 own country, under the control of the commis- 
 sion of Historical Monuments. At one glance 
 any one will perceive the immense and im- 
 
OF THE SCIENCE. 
 
 41 
 
 portant influence which the photographic pro- 
 cesses are destined one day to exercise upon that 
 great national enterprise ; each will compre- 
 hend how much these novel modes of proceeding- 
 are distinguished by economy, a species of merit 
 which rarely advances with the arts in the per- 
 fecting of their products. 
 
 " If it should at length be asked, if the art, 
 defined in its very appellation, can bear the 
 examination of its productions, those productions 
 which are formed by the most subtle and deli- 
 cate agent that nature offers, rays of light, M. 
 Paul Delaroche shall answer. 
 
 " In a note replying to our request, that cele- 
 brated painter declares, concerning the process of 
 M. Daguerre, that it so far contains the per- 
 fection of certain conditions essential to art that 
 they would become, even to the most accom- 
 plished painters, a subject for observation and 
 study ! That which struck him in the designs 
 is an inconceivable precision, nothing that 
 disturbs the tranquillity of the masses, no- 
 e 3 
 
42 
 
 NATURE AND OBJECTS 
 
 thing that in any manner obscurates the ge- 
 neral effect. 
 
 " ' The correctness of the lines, besides,' says 
 M.Delaroche, 'the precision of the forms, is as 
 complete as possible in the designs of M. Da- 
 guerre, while, at the same time, there may be 
 recognised a model of a large object, forcible 
 and like, as rich in tone as effect. The painter 
 would find in the process a prompt means of 
 making a collection of studies, which he could 
 not obtain otherwise but with the expenditure of 
 much time, with much labour, and in much less 
 perfection, setting aside the necessity for his 
 own talent.' After having combatted, by excellent 
 arguments, the opinions of those who imagine 
 that photography would be injurious to our ar- 
 tists, and especially to our engravers, M. Dela- 
 roche concludes his note with this remark, ' To 
 resume, the admirable discovery of M. Daguerre 
 is an immense service rendered to the arts.' 
 
 " We can commit no error in adding nothing 
 to such evidence." 
 
OF THE SCIENCE. 
 
 43 
 
 Nor can we ; for a better illustration of the ob- 
 ject of the Daguerrotype than the whole of this 
 extract furnishes could not have been given. 
 But as one circumstance, which beautifully 
 proves the necessity, — for such we may call it, — 
 that exists for the exceeding delicacy of the de- 
 signs produced by this instrument, we may state 
 that the exceeding thinness, the almost incon- 
 ceivable tenuity of the coating of nitrate of sil- 
 ver, to speak simply, obliges a remarkable fine- 
 ness in every part of the product; a coarse 
 representation could not be produced at all, 
 there must be either a fine design or none \ for 
 a coarse representation could not but become no 
 picture or representation, for it must evince such 
 confusion in the details that the outline of no 
 object whatever could be perceived. 
 
 But one of the greatest advantages of the 
 Daguerrotype consists in this, that it acts with 
 a certainty and extent to which the powers of 
 human faculties are perfectly incompetent. 
 Not only does it delineate every object presented 
 
44 
 
 NATURE AND OBJECTS 
 
 to its operation with perfect truth in their pro- 
 portions, perspective, and tint— an attainment 
 to which artists could never quite arrive, 
 though which some of them of first-rate genius, 
 after long and indefatigable labour, might per- 
 haps so closely imitate as to satisfy, if not de- 
 ceive, the casual observer — but it lays down 
 objects which the visual organs of a man would 
 overlook, or might not be able to perceive, with 
 the same minuteness, with the same particularity, 
 with the same nicety, that it depicts the most 
 prominent feature in the landscape. The leaf 
 of a rose, the blades of grass, the neglected 
 weed, the time-stained excrescences on the 
 knarled oak tree trunk in the landscape, and 
 the smallest filament of tracery in the en- 
 tablature, or in the representation of human 
 passions on the loftiest point of a carved pedi- 
 ment of a temple, could be traced with 
 the same accuracy, in every respect, as the 
 varied workings of the soul in the countenance 
 of the hero of the piece ; and thus, by a cool ob- 
 
OF THE SCIENCE. 
 
 45 
 
 server, scenes of thrilling interest in the pro- 
 gress of life may be transcribed and conveyed 
 to posterity, not as they seem to the ima- 
 gination of the poet or the painter, but as 
 they actually are. 
 
 Nothing indeed but close application to dis- 
 cover all the principles of the Daguerrotype, 
 — who indeed can say when they shall all be 
 discovered, — is necessary to its universal use in 
 examining, analyzing, modifying, and applying 
 to the benefit of society, that most universal of 
 all the agents which God has given for the 
 beauty and advantage of his creation. 
 
 Were there uncertainty in its operation, we 
 should esteem the value of this new instrument 
 at a very much lower rate, but such is not the case. 
 The objects themselves are, in one sense, their 
 own delineators, and perfect accuracy and truth, 
 — strange that we should have to say so of any 
 thing earthly, — are necessitated. It has indeed 
 been observed by an acute philosopher, that it is 
 no improbability that we may obtain an accurate 
 
46 
 
 NATURE AND OBJECTS 
 
 chart of the lunar world by the moon herself. 
 It says nothing to object to all this, that the 
 action of the Daguerrotype is at present incom- 
 plete, for the faculty of accomplishing all is 
 evidently there, and it requires only the skill of 
 mental power to develop it. 
 
 A very short time suffices to make an intelli- 
 gent person, altogether ignorant of the instru- 
 ment, well acquainted with its nature and use; 
 and, after but few trials, any one must succeed 
 in obtaining perfect specimens of art. M. 
 Arago, for instance, one of the reporters on the 
 Commission of Inquiry to the French Cham- 
 ber of Legislature, after he had been made ac- 
 quainted with the process, executed a beautiful 
 piece on his very first attempt. 
 
 The very high price at which the instruments 
 have been sold in Paris has prevented the art 
 from progressing in the way that the well-wishers 
 of science could desire. But this is an evil which 
 time will surely rectify, and very shortly it may 
 be confidently anticipated that an efficient instru- 
 
OF THE SCIENCE. 
 
 47 
 
 ment may be obtained for the expenditure of 
 10/. or 12/. and even less. 
 
 The more generally the science is diffused 
 and practised, the more useful must it become, 
 and it is hoped that this little manual will be in 
 some degree beneficial in promoting both of 
 these desirable objects. 
 
48 
 
 MATERIALS USED IN THE ART. 
 
 The first thing necessary is the plate on 
 which the drawing is to be made. M. Daguerre 
 found a leaf of copper, plated with silver, both 
 metals together not being thicker than a card, 
 the best receptacle or receiver for the rays of 
 light ; and as he has been the most successful 
 draughtsman by the aid of Heliography, we 
 will in the first place follow him in describing 
 the implements used as laid down in ex- 
 posing his process to the French Legislative 
 Chambers, and then make our readers ac- 
 quainted with the other materials which have 
 been employed for the purpose. 
 
 The object of the copper is simply to sup- 
 port the silver, which must be the purest that 
 can be procured. But, though the copper should 
 be no thicker, if possible, than to serve the pur- 
 pose of support, it is necessary to be thick 
 
MATERIALS USED IN THE ART. 49 
 
 enough to prevent the plate being warped, and 
 thus distorting the images traced upon it. 
 
 The plate has to be polished ; and, for this 
 object, there is required, 
 
 A phial of olive oil. 
 
 Some very fine cotton. 
 
 A little pumice powder, ground till it is 
 almost impalpable, and tied up in a piece of 
 fine muslin that is thin enough to suffer the 
 powder to pass through without touching the 
 plate when the bag is shaken. 
 
 A little nitric acid diluted with sixteen times, 
 by measure, its own quantity of water. 
 
 A frame of wire, on which to place the plate 
 when being heated. 
 
 A spirit lamp, to make the plate hot. 
 
 A small box with inclined sides within, and 
 having a lid to shut it up close, as represented 
 in figures 1 and 2. 
 
 A square board large enough to hold the 
 drawing, and having catches at the side to keep 
 it steady, as shown in figure 3. 
 
 F 
 
MATERIALS USED 
 
 FRAME FOR PLATE 
 
IN THE ART. 51 
 
 Four metallic bands, to meet the catches of 
 the board, the form of which is represented in 
 the plate under the preceding figure. 
 
 A small handle. 
 
 A box of small tacks. 
 
 A small bottle of iodine. 
 
 A Camera Obscura large enough to admit 
 the plate of the largest drawing intended to be 
 used. The nature of this amusing apparatus 
 is so well known that we need not here attempt 
 to describe it. But as the object of this little 
 treatise is, not only to make the invention known, 
 but to induce a more general application of the 
 art and science of Heliography to useful pur- 
 poses, the writer of these pages may as well 
 observe that, when a boy, he manufactured a 
 very effective camera, at, he believes, no greater 
 charge than eighteen pence. It was about 
 eight inches long, as many deep, and about six 
 inches wide. Take a box of the requisite di- 
 mensions, with a rising lid ; attach to the in- 
 terior of the lid, on the front and two sides, a 
 
52 
 
 MATERIALS USED 
 
 piece of thick basil leather, all in one piece, 
 so managed that when the lid is raised the light 
 will be excluded from the interior of the box. 
 This will be done if the leather be so adjusted 
 to the lid that it work closely on the outside of 
 the box, and checked that the lid cannot be 
 raised beyond an angle of 45 degrees. When 
 the lid is raised, cut an aperture in the front 
 of the leather, only large enough to enable the 
 spectator to obtain easy sight of the interior of 
 the box. The hinge, or front part of the lid 
 must also be so covered as to exclude the light. 
 In front of the box itself, a round hole should 
 be cut about half way down, into which a tube 
 must be fixed about 2i inches long, having two 
 lenses in it, one at the extremity, and a second 
 about If inches within it. The tube must be 
 so fixed in the box as to exclude all light from 
 the box, except that which is transmitted 
 through it. Inside the box, about half an inch 
 above the tube, a little ledge must be fastened ; 
 on this ledge a piece of ground glass must be laid, 
 as large as the box will hold. The Camera is 
 
IN THE ART. 
 
 o3 
 
 then complete, and, apart from its use in the pur- 
 pose which has led us to speak of it, we may say 
 that a more pleasing addition cannot he made to 
 the sources of innocent gratifi cation which the 
 reader may possess. A machine more artlike 
 in its construction, hut not a whit more efficient, 
 is represented in the accompanying figure. 
 
 CAMERA OBSCURA. 
 
 A phial of mercury, containing about 3 oz. 
 
 A lamp and spirit of wine. 
 
 A deep box or black iron vessel, represented 
 below, with a cup attached to its lower part, 
 and a black iron frame, inclined at 45 degrees 
 in the upper half, on which to lay the plate for 
 F 3 
 
54 MATERIALS USED 
 
 the disengaging process, to be described here- 
 after. It should have a lifl to cover it com- 
 pletely, and the front be formed of glass with a 
 shutter to it. 
 
 BOX FOP niSKVCAOIttr. PROCESS. 
 
IN THE ART. 
 
 55 
 
 A large cup or open vessel to be put under- 
 neath the bottom of this box, with a ther- 
 mometer fixed upright within it, to ascertain 
 the degree of heat. The whole apparatus is 
 faithfully represented in the figures below. 
 
 BOX WHEN CLOSED. SECOND VIEW. 
 
66 
 
 MATERIALS USED 
 
 A glass funnel with a long neck, to pour the 
 mercury into the vessel beneath the bottom 
 of the box. 
 
 A solution of common salt in clear water, in 
 the quantities of one of salt and three of 
 water. When thoroughly dissolved, this solu- 
 tion should be filtered through 
 thick paper, and then kept in 
 corked bottles. 
 
 A covered jug, having a 
 beak to pour out of, filled with 
 distilled water. 
 
 An inclined plane, fixed up- 
 on a frame with catches to 
 hold the drawing. The ob- 
 ject of these catches is, to 
 prevent the fingers touching 
 the plate. The purpose of the 
 inclined plane is, to support the drawing, whilst 
 hot distilled water is poured over it, in order to 
 free it from any particles of the iodine which 
 has been used in the disengaging process. 
 
 FILTERING PROCESS. 
 
IN THE ART. 
 
 57 
 
 \ 
 
 INCLINED PLANE, SIDE VIEW. 
 
 FRAME FOR INCLINED PLANE. 
 
 Lastly, a handle or hook, wherewith to take 
 hold of the drawing when in the cleansing 
 trough. 
 
 These, we believe, are all the requisites de- 
 scribed as necessary for the photographic art 
 by M. Daguerre ; but it has been discovered that 
 other substances, much more convenient for the 
 purposes of the art, are almost equally, if not 
 quite, as fitted for them as metallic plates. 
 Our countryman, Mr. Talbot, F.R.S., who was, 
 if not the prior inventor, at least contemporaneous 
 with M. Daguerre in attaining a knowledge of 
 Heliography, has given the following directions 
 for the making of photogenic paper, which we 
 extract at length on account of the importance 
 of the matter they contain. 
 
58 
 
 MATERIALS USED 
 
 " To prepare Photogenic Paper. 
 
 " The paper, being cut to the required size, 
 is to be dipped into a solution of salt in water, in 
 the proportion of half an ounce of salt to half 
 a pint of water ; let the superfluous moisture 
 drain off, and then, laying the paper upon a 
 clean cloth, dab it gently with a napkin, so as 
 to prevent the salt collecting in one spot more 
 than another. The paper is now to be pinned 
 down by two of its corners on a drawing board, 
 by means of common pins, and one side washed 
 or wetted with the Photogenic fluid, using the 
 brush prepared for that purpose, aud taking 
 as much care to distribute it equally as if you 
 were laying in a sky in a water-colour drawing : 
 dry the paper now, as rapidly as you can, at the 
 fire ; the paper will be fit for use for most pur- 
 poses. If, when the paper is exposed to the 
 sun's rays, it should assume an irregular tint, a 
 very thin extra wash of the fluid will render the 
 
IN THE ART. 
 
 59 
 
 colour uniform, and, at the same time, somewhat 
 darker. 
 
 " Should it be required to make a more sen- 
 sitive description of paper, after the first appli- 
 cation of the fluid, the solution of salt should 
 be applied, and the paper dried at the fire ; ap- 
 ply a second wash of the fluid, and dry it at the 
 fire again ; employ the salt a third time, dry it, 
 and one more application of the fluid will, when 
 dried, have made the paper extremely sensitive. 
 If greater sensibility is required, a fourth appli- 
 cation of the fluid will effect the purpose. In 
 the next place, write a number or a letter on the 
 back of each piece of paper, and cut a narrow 
 slip from the edge of each, marked in a corres- 
 ponding manner. Expose these slips to the 
 action of the daylight, not the sunshine, and 
 notice the order in which they become dark. 
 Those which are soonest affected by the light 
 are the best prepared, and the sheets from which 
 they were cut should be preserved for the most 
 particular purposes. 
 
60 
 
 MATERIALS USED 
 
 "It is needless to observe that the paper 
 must be kept away from daylight. 
 
 " Cautions to be strictly observed in preparing 
 and using the Photogenic Paper. 
 
 *' 1st. Remember that if the Photogenic 
 fluid falls upon any substance, it will make an 
 indelible black stain, and cannot even be re- 
 moved from the hand until the skin peels off. 
 
 " 2nd. Be particularly careful that the paper, 
 when used, is perfectly dry, or there will be 
 danger of its staining the object laid on it to 
 copy. If perfectly dry, it will not injure the 
 most delicate piece of lace. 
 
 " 3rd. The vessels into which the fluid is 
 poured must be glass or earthenware, and the 
 brushes must not be set in tin, nor must metal 
 of any kind come in contact with the fluid. 
 
 " 4th. Take great care that none of the solu- 
 tion of salt drops into the fluid ; it would render 
 it turbid and almost useless. 
 
IN THE ART. 
 
 61 
 
 " 5th. The paper should be prepared by 
 candle-light. 
 
 " 6th. Immediately after using the brush in 
 the fluid, let it be well washed in water. 
 
 " 7th. No more of the fluid should be 
 poured out than can be used at the time, as 
 there is danger, in pouring it back into the 
 bottle, that some trifling portion of salt may be 
 mixed with it, which would render the liquid 
 turbid. 
 
 " 8th. To avoid the danger of staining the 
 fingers or dress, the vessels employed in the 
 process should be thrown into a basin of water 
 directly they are done with. We recommend 
 gloves to be worn while the paper is prepared." 
 
 G 
 
62 
 
 PROCESS OF PHOTOGENIC DRAWING. 
 
 M. Da guerre divides the whole process into 
 what he calls five operations. The object of 
 the first is to prepare the plate for receiving the 
 sensitive coating on which the drawing is to be 
 traced. The object of the second is to apply 
 this coating. That of the third, placing the 
 plate in the camera obscura, in order to receive 
 the impress of the natural images through the 
 agency of light. The object of the fourth 
 operation is to bring out the invisible drawing on 
 the sensitive coating, and make it apparent. 
 That of the fifth is to prevent the influence of 
 the rays of light on the prepared plate, which 
 would otherwise become black all over alike, and 
 so necessarily destroy the drawing : thus, so 
 far as it has yet been possible to ascertain, com- 
 pleting the process of the art. 
 
PHOTOGENIC DRAWING. 
 
 63 
 
 Preparation of the Plate. 
 
 The medium upon which the representations 
 of natural objects is received is a coating of 
 silver on a plate of copper. In order to meet 
 the requirement of exceeding delicacy, which 
 the subtle agent employed in the delineation 
 needs, it is necessary that the surface should be 
 perfectly smooth, and, which is almost saying the 
 same thing, highly polished. The plate then of 
 copper, covered with the purest silver, both to- 
 gether being of the thickness of about a common 
 card, — we repeat some of these statements, in 
 order to ensure as much perspicuity as possible, 
 — must be laid, with the silvered side upwards, 
 flat, upon several folds of paper, for a bedding. 
 Having been well polished in the usual way, 
 the surface must be powdered equally and care- 
 fully all over with pumice, ground down in a 
 porphyry pestle and afterwards with a muller on 
 plate glass, enclosed in the muslin bag. Then, 
 taking a little cotton wool dipped in olive oil, 
 
64 
 
 PROCESS OF 
 
 the operator must rub it over the plate with 
 rounding strokes, and then crossing them by 
 others, which commence at right angles with the 
 first. By this means the plate is rubbed with 
 the most even touch that the human hand can 
 attain. This process must be repeated fre- 
 quently, of course changing the cotton and 
 renewing the pumice powder every time. When 
 well polished, the oil and pumice must be 
 rubbed off, the plate powdered all over again 
 with pumice powder, and that again rubbed off 
 with dry cotton, with the same sort of rounding 
 and cross strokes as before. 
 
 A small portion of cotton must now be rolled 
 together, and moistened with the diluted nitric 
 acid, by applying it to the mouth of the phial, 
 being at the same time gently pressed with the 
 fingers, so that only the centre is moistened with 
 the acid. This must be applied equally to the 
 whole surface. Let the cotton be changed, and 
 apply as before, until the whole of the surface 
 has been completely visited. Should the acid 
 
PHOTOGENIC DRAWING. 
 
 65 
 
 run into small drops or globules, as is not un- 
 likely, from the high polish, they must be 
 broken down as quickly as possible, but with all 
 gentleness, as, should the acid remain on any 
 particular spot, it will leave a stain or defect 
 upon the drawing. It will be seen that the 
 acid has had a sufficient effect upon the plate 
 by the appearance of a sort of veil upon the 
 polish. When this is perceived the pumice 
 must be powdered over again, and then cleaned 
 with fresh cotton as before, being particularly 
 careful not to occasion any inequality on the 
 face of the plate. 
 
 The next thing to be done is to make the 
 plate thoroughly and equally hot. For this 
 purpose Daguerre used the frame of wire 
 represented in the figure. He placed the 
 
66 
 
 PROCESS OF 
 
 ®- ■ 1 I a 
 
 FKON'f VI KW. 
 
 plate upon this and then applied the spirit 
 lamp to the whole of the under surface. But 
 a better plan is to hold the plate with a pair of 
 pincers, by the corner, over a charcoal fire, as 
 the influence of the heat is likely to be more 
 equally obtained. Soon as the plate is suffi- 
 ciently hot/ a white coating will be observed 
 upon the silver, which indicates that that part 
 of the operation is finished. 
 
 An even cold surface is next wanted, such as 
 a plate of metal or of stone ; M. Daguerre sug- 
 gests a marble table, but perhaps it would be 
 better to use a metallic plate, cooled almost to 
 the freezing point by muriate of soda ; and 
 to this the heated plate must be suddenly trans- 
 
PHOTOGENIC DRAWING. 
 
 67 
 
 ferred. When quite cold the plate must be again 
 polished, in order to remove the gummy ap- 
 pearance of the surface, using the precaution to 
 employ only dry cotton, as before, and care 
 being taken to keep the fingers from the plate. 
 Having finished the polishing, the operation of 
 the diluted acid must be repeated three times, 
 dry powder being dusted over the plate each 
 time, and then rubbed off with dry cotton, so 
 that not the slightest stain be left upon the 
 surface. 
 
 The last operation of the acid must be re- 
 peated always immediately before the plate is 
 put into the camera for the drawing process, 
 and especial care must be taken to remove every 
 particle of dust with cotton wool, both on the 
 surface and back of the plate, before it is used. 
 Should the plate not be wanted for immediate 
 use, the application of the acid, after cleansing 
 the plate from the gummy appearance, must be 
 dispensed with, and then the plate can be stored 
 up for a future period. 
 
68 
 
 PROCESS OF 
 
 The Coating. 
 
 The object of the next operation is to give 
 the plate that sensitive coating on which the 
 light is to delineate the most delicate of its 
 strokes. 
 
 For this purpose a cup containing iodine, 
 broken in pieces in order to render the exhala- 
 tion more equal and rapid, is placed at the 
 bottom of the box first described. It is neces- 
 sary that the exhalation of the iodine should be 
 managed as well as possible, in order to avoid 
 the fault of forming vesicles in the centre of the 
 plate, which would otherwise ensue, and thereby 
 prevent the equal formation of the coating, 
 which is essential to the perfect success of the 
 whole process. The plate is then put into the 
 box with the face downward, and supported 
 by small brackets at the corners. In this 
 position the plate must remain until it assumes 
 a full gold colour through the condensation of 
 the iodine on its surface. If the plate remain too 
 
PHOTOGENIC DRAWING. 69 
 
 long it will become of a violet colour, if not long 
 enough it will be of a pale straw colour ; either 
 of these two states is inimical to the desired ef- 
 fect. The gold colour, and nothing but that, 
 is the indication of the right state of the plate. 
 
 Circumstances alone can regulate the length 
 of this part of the process, as it dejjends upon a 
 variety of causes — chiefly the temperature of the 
 apartment in which the process takes place. 
 No other heat should be used for the evapora- 
 tion of the iodine than that of the apartment in 
 which it goes on ; and it should be particularly 
 observed that the temperature within the box 
 should be equal to that of the surrounding 
 atmosphere, as, otherwise, moisture settles upon 
 the surface of the plate, which is a grand fault. 
 Practice alone can enable the experimenter to 
 judge of the recpiisite time for the condensation 
 of the iodine ; the period varies from five 
 minutes to half an hour. 
 
 It is of course necessary that the plate should 
 be examined during the process, in order to as 
 
70 
 
 PROCESS or 
 
 certain its colour. To do this well requires some 
 little judgment and dexterity, for if the plate 
 be exposed to much light the effect is injured. 
 It is better therefore to carry on this part of 
 the operation in a dark room, where a little 
 side light is admitted. Having turned up the 
 lid of the box, lift the plate quickly with both 
 hands, and a momentary glance will suffice to 
 show the colour. If the tint be too dark the 
 whole operation must be gone over agaiu, 
 polishing the plate as before. If the tint be too 
 pale the plate must be replaced until the requi- 
 site hue has been obtained. 
 
 When this desirable point is arrived at, the 
 plate should be immediately fixed in the frame re- 
 
 FRAME FOR THE PLATK. 
 
 presented in 
 the annexed 
 fgvre, fast- 
 ening it with 
 catches and 
 bands, and 
 then placing 
 
PHOTOGENIC DRAWING. 71 
 
 it immediately in the camera. As at this stage 
 of the process the plate is remarkably sen- 
 sitive to light, the transference from one recep- 
 tacle to the other must be made as quickly as 
 possible, and with only just so much light as 
 will enable the operator to see what he is about ; 
 for instance, that of a small taper in a darken- 
 ed room. 
 
 This transposition should not be delayed 
 longer than an hour at the most, as after that 
 period the iodine and the silver lose something 
 of the power of their combined action. 
 
 On placing the plate in the box for the ope- 
 ration of coating, the cover should be shut down 
 very gently, lest the sudden compression of the 
 air should drive any of the particles of the 
 iodine upon the surface of the plate, which 
 would occasion large stains, and consequently 
 spoil the drawing. It will also be advisable 
 to cover the cup with gauze, as that tends to 
 occasion a more equal exhalation of the iodine 
 as well as to the avoidance of the defect just 
 
72 
 
 PROCESS OF 
 
 spoken of. Lastly, between the coating of one 
 plate and that of another, the box should be 
 turned upside down and thoroughly cleaned from 
 all the particles of iodine, being at the same 
 time careful that none remains upon the fingers. 
 
 The Camera Obscura. 
 
 The next operation is to obtain the drawing. 
 Having placed the Camera in front of the scene 
 of which the representation is desired, and the 
 glass through which the scene is conveyed to the 
 interior of the box being adjusted to the right 
 focus, the ground glass of the camera is with- 
 drawn, and the prepared plate, with the face 
 downwards, is substituted for it. Then, fastening 
 it properly with screws or pins in order to 
 save all shaking and uncertainty in the depiction, 
 the whole is left until the natural images are 
 drawn by the natural light on the plate. 
 
 This is the nicest and most difficult portion 
 of the whole of the process. The time which 
 it is necessary to leave the plate for a complete 
 
PHOTOGENIC DRAWING. 73 
 
 delineation of the objects depends upon the 
 intensity of the light; consequently, the state 
 of the weather will have very considerable in- 
 fluence. A dull day will require more time 
 than a bright one ; and objects in the shade, 
 on a bright day, will require more time for 
 their delineation than those in the broad light, 
 even on a dull day. The full clear light of 
 the south of Europe, Spain, and Italy, for 
 instance, will effect the object much more 
 speedily than the duller luminence of a more 
 northern clime. And the observation of course 
 holds with still greater force respecting the 
 more glowing brilliancy of tropical countries. 
 Nor should it be lost sight of that some 
 hours of the day are more favourable than 
 others for the photographic, or heliographic 
 process, whichever we may call it. M. Da- 
 guerre says that " the most favourable time 
 is from seven to three o'clock, and a drawing 
 which could be effected at Paris in three or 
 four minutes, in the months of June and July, 
 
 H 
 
74 
 
 PROCESS OF 
 
 would, in May or August, require five or 
 six, and seven or eight in April or September." 
 These can only be general data, for the state 
 of the atmosphere must be taken into account 
 as well as time of day and season of the year, 
 and the brightness or shade of the objects 
 to be delineated. From three to thirty mi- 
 nutes was the time needed, according to M. 
 Daguerres experience at Paris. 
 
 But it is of little importance that we are 
 unable to give any positive directions on this 
 subject ; for the experimenter can always readily 
 rectify his own mistakes. Should the drawing 
 be too much blackened by an over-prolonged 
 solarization, the next plate must be withdrawn 
 sooner; should the details be too vague and 
 indistinct, the next plate must be submitted 
 longer to the action of the light. Perhaps 
 we cannot do better than subjoin here Mr. 
 Talbot's directions. 
 
PHOTOGENIC DRAWING. 
 
 75 
 
 To produce a Photogenic Drawing. 
 
 " The following method is applicable to the 
 purpose of obtaining copies of leaves of plants 
 and flowers, prints and paintings on glass, 
 
 " The apparatus employed to copy the above 
 objects consists of a wooden frame like that 
 
 pressed upon the glass when llLiii« __ 
 necessary, in the usual man- 
 ner. The glass being downwards, and the 
 back-board removed, the object to be copied 
 is laid upon it (the glass), and a piece of 
 prepared paper of sufficient size is laid on 
 tbis object, the prepared side touching it : 
 
 wings of insects, sea-weeds, lace, &c, &c. 
 
 of a small looking-glass, in 
 which a plate of clear glass is 
 placed, resting on a rabbet 
 in the usual manner, over 
 which is a cushion of silk, 
 fixed to the back-board, and 
 
76 
 
 PROCESS OF 
 
 BACK-BOARD. 
 
 over this you place the cushion and back-board, 
 and force it gently against the glass, by means 
 of the cross-pieces. When all this is done, 
 the glazed side of the frame is held opposite 
 the sun, and the drawing is made in a shorter 
 or longer time, according to the brightness 
 of the sunshine, and the goodness of the 
 prepared paper. When sufficiently darkened, 
 it is to be removed into the shade, and taken 
 out of the frame, to be afterwards fixed in 
 the manner we shall presently explain. 
 
 " Cautions in taking a Photogenic Drawing 
 by Transmission of the Suns rays. 
 
 " 1st. It is absolutely necessary, to the ob- 
 
PHOTOGENIC DRAWING. 
 
 77 
 
 tainment of a clear drawing, that the object 
 to be copied should lie close to the surface 
 of the prepared paper. 
 
 " 2nd. It is best to cut the paper into the 
 requisite sizes by candle-light, and to mark 
 the back of each piece so that it may be 
 known at once; for, if there is any delay, 
 the surface undergoes a partial change of colour, 
 and the drawing is less distinct." 
 
 h 3 
 
78 
 
 DISENGAGING PROCESS. 
 
 Immediately on removing the plate from the 
 camera it should be placed on the inclined frame 
 in the box previously described, and which is 
 represented in the figure. Having placed 
 a cup at the box or iron vessel, — for this 
 latter article is in every respect the better for 
 the purpose, — let it be filled with mercury by 
 means of the long glass funnel specified in 
 the list of articles necessary for the art. Then, 
 taking the plate fixed in the frame in which 
 it was placed in the camera, put it with the 
 face downwards within the ledge in the in- 
 clined frame, so that it can be seen through 
 the glass in front of the box or vessel, and 
 afterwards close the lid very carefully so that 
 none of the particles of mercury are disturbed. 
 All these being thus rightly disposed the 
 spirit lamp should be applied to the bottom 
 
PI SENG AG TNG PROCESS. 
 
 79 
 
 SPIRIT LAMP. 
 
 of the cup containing the mercury, until the 
 bulb of the thermometer in the cup shows a 
 heat of about 140 degrees of Fahrenheit, when 
 the lamp should be removed, and the mercury 
 will continue to rise without its aid. But it 
 should not be suffered to exceed 177 or 178 
 degrees. 
 
 When the plate is first placed in the iron 
 vessel the natural images drawn by the light 
 will be invisible, but in the course of a few 
 minutes, a faint tracery will begin to appear, 
 and the progress of its development may be 
 watched by removing the wooden screen to 
 the glass window, and using the light of a 
 small candle at different intervals, being par- 
 ticularly careful that the rays of the candle 
 flame fall as obliquely and as little upon the 
 plate as possible. When the . sketch is suffi- 
 
80 
 
 DISENGAGING PROCESS. 
 
 FRAME FOR HOLDING DRAWING. 
 
 ciently developed, the plate should be with- 
 drawn, for the operation is then completed. 
 But it should be observed that, after having 
 risen to the highest heat specified above, the 
 temperature will recede, and by the time, or 
 before, the plate is finished, will be reduced to 
 120 or even 100 degrees. The degree, indeed, 
 often suffices to show the state of the plate, 
 and it may generally be confidently relied 
 upon that, when the thermometer has fallen 
 to 100 or 105, the operation is completed; but 
 observation of the drawing itself is the best 
 mode of judging. 
 
DISENGAGING PROCESS. 
 
 81 
 
 DRAWING ON FRAME, 
 
 The sketch may now, if necessary, be kept 
 for a considerable period, provided it be saved 
 from frequent exposure to the light; care 
 also being taken that the surface is not 
 rubbed. But the better plan is to proceed 
 at once to 
 
82 
 
 FIXING THE IMPRESSION. 
 
 The object of this operation is to prevent 
 the destruction of the drawing, through the 
 discolouration of the plate by the decompo- 
 sition of the iodine by light. This is done 
 by a thorough cleansing of the plate. For 
 this purpose, the two troughs must be placed 
 at a convenient distance from each other, and 
 one filled with pure water and the other with 
 the saline solution. The plate must first be 
 placed in the trough of plain water and 
 moved about freely with the wire handle or 
 
 hook until the surface has been well mois- 
 tened. It must then be plunged into the 
 solution and subjected thoroughly to its action, 
 as it was before to that of the water, and, 
 when the yellow colour has disappeared, it 
 should be lifted out with both hands and 
 
FIXING THE IMPRESSION. 83 
 
 placed upon the in- 
 clined tablet upon 
 the stand, being well 
 secured that it does 
 not fall. Then, hold- 
 ing the jug contain- 
 ing the distilled wa- 
 ter at an elevation 
 of about a foot above 
 the plate, pour the 
 water in one con- 
 tinued forcible stream 
 upon it, taking care 
 that it freely and fully inclined tablet. 
 washes every part of the sketch. The dis- 
 
84 FIXING THE IMPRESSION. 
 
 tilled water should be hot to render it more 
 efficient, and enough of it should he used to 
 thoroughly cleanse the plate from every par- 
 ticle of the saline solution. Should any glo- 
 bules of water remain upon the plate they 
 should be removed by blowing upon them. 
 But, in order to render our instructions as com- 
 plete as possible, we will add Mr. Talbot's 
 directions for fixing the drawing as given in 
 the Literaiy Gazette. 
 
 " To fix the Drawings. 
 
 u First method. — After the drawing has been 
 made by the action of the sun's rays, it is 
 to be dipped into the solution of salt in water ; 
 when taken out, the superfluous moisture is to 
 be removed, and the paper dried at a fire ; after 
 this it is but little injured by a partial ex- 
 posure to the rays of the sun, and remains 
 unchanged if kept in a portfolio, or only ex- 
 posed to common daylight. 
 
FIXING THE IMPRESSION. 85 
 
 u N.B. If the drawing is very dark, asaturated 
 solution of salt is necessary. 
 
 " Second method. — - This method fixes the 
 drawing with more certainty, but requires 
 greater care in its application ; instead of 
 the solution of salt, a small quantity of iodide 
 of potash is used in the same manner; but 
 if it is in the least degree too powerful, it 
 attacks the dark part of the drawing and de- 
 stroys it, and, if not sufficiently strong, it 
 acts so slightly on it, as to leave the paper 
 still liable to change on exposure to the light. 
 
 " To ascertain if it is of the requisite degree 
 of strength, it must be tried on the edge of 
 the paper on which the drawing is made ; 
 and, if it change the dark parts to a prim- 
 rose colour, it is too strong and must be 
 diluted. A sixth part of the quantity of iodide 
 in the bottle will be, in general, sufficient for 
 a large wine glass full of water." 
 
 The sketch is now finished, and when dry, 
 the plate should be stored away from the 
 i 
 
86 TO OBVIATE DEFECTS. 
 
 dust or any substance that would bring a 
 tarnish on the silver, and where nothing can 
 rub it ; for the mercury by which the images 
 are rendered visible is partially decomposed, 
 and, though it is not injured by washing, will 
 not bear the slightest touch or rub. The best 
 plan of preserving the drawings is to put them 
 in a frame having a ledge raised above the 
 surface of the drawing and protected by a 
 covering which does not touch the plate." 
 
 TO OBVIATE DEFECTS. 
 
 One thing is especially needed in prac- 
 tising the art of Heliography, extreme care 
 throughout the whole process. During the 
 operation of polishing and preparing the plate 
 it is necessary that it should be rubbed by the 
 pumice powder as evenly as possible, and 
 that the diluted nitric acid does not accu- 
 mulate in drops or globules, as their presence 
 leaves stains on the surface of the plate which 
 will appear in the drawing. 
 
TO OBVIATE DEFECTS. 
 
 87 
 
 During the second operation of coating the 
 plate, the time when the plate assumes the 
 right tint of full gold colour should be strictly 
 observed, and the plate should be removed 
 neither before nor suffered to remain after 
 that time. Any defect at this stage necessi- 
 tates the repolishing of the plate. The plate 
 may be repolished and used over again until 
 the silver is worn through to the copper. 
 
 Taking the drawing in the camera re- 
 quires only care in placing the plate squarely 
 in the box, and the exercise of good judg- 
 ment as to the time it should be left there. 
 Experience alone will enable the experimenter 
 to become an adept in the knowledge of this 
 time, and with the hints we have given him, 
 but little practice, we should think, would 
 suffice. Failure in one trial should be followed 
 immediately by another attempt, as success in 
 the second is almost sure to correct error in 
 the first. 
 
 The disengaging process is, perhaps, the 
 
88 
 
 TO OBVIATE DEFECTS. 
 
 most difficult portion of the art, but care here, 
 as in other instances, will ensure good for- 
 tune ; observation as to the precise moment 
 of removing the plate being the principal 
 requisite. When the mercury is done with, 
 it should be removed by means of the sy- 
 phon cock at the side, and the inside of 
 the vessel should be carefully cleared from 
 any particles of mercury that might adhere 
 to the sides ; and the holds, catches, and bands, 
 must be carefully cleared from it with pumice 
 powder and water after each experiment. 
 
 The mode of fixing the drawing is so 
 simple that no person of ordinary intelligence 
 can, we think, make a mistake in it. 
 
 Should after all the drawing not be satis- 
 
TO OBVIATE DEFECTS. 
 
 89 
 
 factory, the plate may be polished again, 
 and used, as we have said, for reiterated trials, 
 until the silver plating is worn through to 
 the copper. The copper plated with silver 
 may be obtained at any silver plated manu- 
 factory in town or country. 
 
 i 3 
 
90 
 
 CONCLUSION. 
 
 We have here given, as succinctly as is pos- 
 sible, a full account of this novel and in- 
 teresting art, and sincerely trust that this 
 little treatise may conduce by encouraging the 
 practice of it to the amusement and instruction 
 of many a philosophic mind. Heliography 
 has certainly developed a new feature in the 
 physical world; it has made us acquainted 
 with a new secret from that storehouse of ar- 
 cana, by which, through infinite wisdom, wc 
 have been surrounded, and opened up a new 
 pathway to scientific attainment for the welfare 
 and benefit of mankind. It has given us a 
 new proof — a repetition of every discovery in 
 the world of nature and of mind — of the 
 aptness of means to their ends throughout 
 all creation, and the presence of Omniscient 
 Goodness superintending the whole. 
 
9] 
 
 THE ART OF DIORAMA PAINTING. 
 
 The term Diorama is derived from a Greek 
 word signifying to see through, and is a very 
 fair definition of that which it is intended to 
 indicate. Though inferior, we might say far 
 inferior, to the Panorama as a means of re- 
 presenting extensive subjects, it possesses ad- 
 vantages far above those of any other descrip - 
 tion of painting for the production of immediate 
 effect. 
 
 The mode of arranging the picture adds 
 not a little to the illusion which a dioramic 
 view is, even without such aid, well calculated 
 to create. The peculiar object of the diorama 
 is, as most of our readers are aware, the mi- 
 micry of natural changes, while the view is 
 constantly before the eyes of the spectator. 
 Thus, for instance, in one of the scenes lately 
 exhibited at the building erected for the pur- 
 
92 
 
 THE ART OF 
 
 pose in the Regent's Park, the interior 
 of the church of St. Paul, at Florence, 
 when first submitted to the visitors, presents 
 the quietude and solemn repose of a pic- 
 turesque and beautiful place of Christian wor- 
 ship. Its aisles and nave, its pillars, its monu- 
 ments, its altar, and all the other attendant 
 circumstances of such a scene, are observed, 
 illumined by the broad daylight, and inspire 
 that sense of awe which is invariably the 
 result of the inspection of a well ordered ec- 
 clesiastical edifice. 
 
 The fulness of noon decreases, and the 
 fading light of declining day throws a more 
 and more sombre hue over the long drawn 
 aisles, the varied pavement, and fretted roof. 
 The pillars throw stronger shadows, the si- 
 lent memorials of a silent race seem more 
 prominent in the roughness of their sculp- 
 tured ornaments, and less and less distinct in 
 their lower details, until at last the obscurity 
 deepens, as the evening grows, into the gloom 
 
DIORAMA PAINTING. 
 
 93 
 
 that gathers, and spreads and diffuses itself 
 throughout the vast interior, and, at length, 
 wraps every object in its own dim uncertain 
 commingling and congenially confused sha- 
 dows. The hazy gleam, that had thrown 
 its faint and feeble hue in a flickering 
 struggle to dispel the darkening shades, dies 
 away entirely from the topmost pane of the 
 lofty windows, and the pitchy blackness of 
 night settles over all. Then gradually the 
 darkness gives way to growing brightness, and 
 one by one the supports of the building are 
 lighted by brilliant candles, and the whole 
 church is, at length, illuminated for a mid- 
 night mass. Every distant nook is displayed 
 in its minutest part, and the vast instance of 
 architectural skill is bright as if filled by a 
 noontide sun, but with all the peculiarity of 
 artificial light. Then are shown the seats, 
 forms, and clustering figures of a numerous 
 assemblage; the priests in their stoles and 
 copes, and all the imposing accessaries of a 
 
94 
 
 THE ART OF 
 
 Romish rite. The service concludes, the con- 
 gregation retires ; and, at last, the sinking 
 figures of the clerical personages and their 
 attendants depart, as if in life, from before 
 the eye. The lights are successively extin- 
 guished, and utter darkness succeeds to the 
 striking scene. Then the dawn sheds its sha- 
 dowy heralds through the high windows of 
 the roof, the rays grow in strength and 
 brightness, until again perfect day reigns 
 throughout. 
 
 Much of the completeness of the illusion 
 arises from the circumstance of the spectators 
 being placed at a distance from the picture. 
 They sit in a darkened room forming an arc 
 of a circle fitted with concentric seats. Before 
 them is a species of proscenium, less than 
 the picture, which is placed several feet be- 
 yond it, so that minute defects are not evi- 
 dent except to an artistical observer, and 
 on an intent inspection. 
 
 This species of painting was invented by 
 
DIORAMA PAINTING* 
 
 95 
 
 two French artists, M. Daguerre and Bouton, 
 of whom M. Daguerre was the chief. In 
 compliance with the terms of the [agreement 
 through which the French Legislative Cham- 
 bers secured to him his pension of 6000 francs, 
 that gentleman w r as bound to make his whole 
 process of diorama painting public, and the 
 following detail is condensed accurately from 
 his own account. 
 
 Instead of the common canvass used by 
 painters, M. Daguerre employed the finest 
 calico or even lawn, as free from defects and 
 as equally made as he could procure it, and at 
 the same time of as great width, in order to 
 avoid the unsightliness and inconvenience of 
 seams. This canvass, for so we may term 
 it, is primed on both sides with two coatings 
 of parchment size, or more if necessary. 
 
 The first effect is painted on the right side 
 of the canvass, the sketch being first made 
 with lead pencil, as cleanly and lightly as 
 possible ; for the lights of this portion of the 
 
96 
 
 THE ART OF 
 
 design can only be obtained by having the 
 ground untouched by colour, as otherwise the 
 transparency of the medium for the lights of 
 the second effect would be destroyed. The 
 colours used are ground in oil, but laid on 
 with turpentine, using a little animal oil for 
 the deepest shadows, which may be varnished 
 without any detriment to their effect. Ma- 
 nipulation of the colours is pursued precisely 
 in the same manner as for water-colour paint- 
 ing, with the exception of using oil instead 
 of gum, and applying them with turpentine; 
 especial care being taken that the transparency 
 of the canvass is preserved as much as pos- 
 sible, avoiding all opacity of tint, where it 
 would appear to the injury of the second 
 effect. 
 
 The second effect is produced by painting 
 on the wrong side of the canvass, using no 
 other light but that which comes from the 
 first side of the design. By this plan the 
 forms of the first effect are kept transparent, 
 
DIORAMA PAINTING. 
 
 97 
 
 and may be preserved just as they are, or 
 painted over, as may be conceived best. 
 
 In the first place the whole of the canvass 
 (that is, the wrong side) is covered with a 
 blue transparent wash, the tracings of the 
 brush being effaced by a large tool of badgers 
 skin. This wash must be thinner along the 
 seams and selvages than elsewhere. When 
 quite dry, the alterations of the design are 
 sketched, and the artist has then only to 
 model in his light and shade. This is done 
 by means of a tint, of which white is the 
 base, mixing it with lamp black in order to 
 obtain a grey. The strength of the tint is 
 ascertained by viewing it from the right side 
 of the picture. If of right strength it will 
 not be at all perceptible from that side. The 
 gradation of tones is of course obtained by 
 the gradation of this tint. Should the sha- 
 dows of the first side be too strong for the 
 effect on the second, it must be harmonized by 
 the use of the grey tint of the requisite opacity. 
 
 K 
 
98 
 
 THE ART OF 
 
 When this is done, the picture may be 
 properly coloured, using only the most trans- 
 parent tints prepared in oil. The colours 
 must still be applied with turpentine, which 
 produce only a powerful effect in proportion 
 to the repetition of their use ; but, in strong 
 effects, more of oil may be used. For slight 
 effects, however, the essence of turpentine is 
 sufficient. 
 
 Each effect is made clear in its turn by 
 the light used to make it evident. The first 
 effect is shown by reflected light, that is, a 
 light before it, and brought from above. For 
 this purpose, windows are made in the roof 
 behind the proscenium, and, consequently, 
 out of the sight of the spectator, fitted with 
 ranges of shutters, so as to exclude the light 
 gradually. 
 
 In the second effect the light is obtained 
 by refraction, behind the picture, and comes 
 from vertical openings. Only one light is 
 used when one effect is intended to be shown 
 
DIORAMA PAINTING. 
 
 99 
 
 in its full power, but both lights may be 
 employed when a modification of effect is to 
 be produced. The windows ought to be at 
 least seven or eight feet from the painting, 
 in order to prevent, in the first place, the 
 light from appearing in patches — stronger in 
 one part than another ; and, in the second, 
 to allow of the interposition of coloured media, 
 in order to obtain a modification of the light : 
 these means are necessary on both sides o fi 
 the picture. 
 
 M. Daguerre explains the grounds of dio- 
 ramic effect upon the principle of the de- 
 composition of light. He states that, if two 
 colours be put upon canvass, the one red 
 and the other green, and a red glass be 
 interposed between the colours and the light 
 that falls upon them, the red colour will re- 
 flect its consonant rays, but the green will 
 remain black. If green glass be interposed, 
 the converse will take place; the green will 
 show green, but the red will appear black. 
 
100 THE ART OF DIORAMA PAINTING. 
 
 This principle is strictly applicable to dioramic 
 painting. There are two effects ; one before, 
 the other behind, and these effects, not pass- 
 ing into one another but through a complicated 
 combination of tint, lessen the necessity for 
 any strongly marked media for the light to 
 pass through ; for, the light having in both 
 effects to traverse the colours on the canvass, 
 the result is a close similarity to nature in 
 her changes from morning to night, and, by 
 parity of inference, a similarity to all other 
 changes from light to shade. Nor is it ne- 
 cessary to have any very strong tints in order 
 to produce a powerful effect, for even a slight 
 shade is often sufficient for the purpose. 
 
 THE END. 
 
 Clarke, Printers, Silver Street, Falcon Square, London, 
 
THE