On the History and Chemistry of Writing, Printing, and Copying Inks, and a New Plan of Taking Manifold Copies of Written and Printed Documents, Maps, Charts, Plans, and Drawings.

Journal of the Society of Arts 265, 18.12.1857

By John Underwood.

Prior to the invention of printing, when all the business of the world was carried on in writing, and its literature and science deposited in manuscript, the manufacture of a black and durable ink was evidently not only of the first importance, but was recognized as such; and that we have seriously retrograded in this, as well as in many other branches of the Arts cannot be denied; in proof of which we have only to refer to the manuscripts in our possession, when we find that those from the 5th to the 12th century, notwithstanding their greater age, are in a far better state of preservation than those of the last four centuries; for while the writing in the former is always perfect, and, in many cases, as black as if it had just been written, that in the latter is often really not legible. The grounds for this disparity arise partly from the spirit of competition, so rife in the present day, which is always looking after the cheapest article that can be obtained, and also from the rapidity with which it is thought necessary to carry on all business transactions, and which does not allow time for the use of the comparatively thick ink of ancient times; but when we think of the normous amount of property that depends, for its proper transmission, upon the permanence and durability of the ink used in the preparation of title-deeds, wills, &c., I consider that no expense of time or money ought to weigh with us in so preparing them that they shall be unalterable by either age or the skilled arts of those who may desire fraudently to tamper with them.

Many experiments have been made with a view to discover the composition of the ink of the ancients, and the results arrived at from analysis are apparently opposed to each other. The first chemist who devoted his attention to such analysis was Dr. Lewis, to whom we are indebted for much of our present knowledge upon this subject, and who has left us an article upon it full of valuable research in the "Philosophical Commerce of Arts," published in 1763. From his analysis, he comes to the conclusion that the ink of the ancients consisted entirely of fine lamp black or charcoal, held in suspension by some mucilaginous fluid; which opinion was afterwards supported by the experiments of Mr. Thomas Astle, author of a work "On the Origin and Progress of Writing," published about the year 1780; but this view does not at all accord with the results of experiments made by Sir Charles Blagden, which were embodied in a paper read before the Royal Society, in 1787. He states that he had been led to inquiry on thissubject by his friend Thomas Astle, who supplied him with several manuscripts dated from the 9th to the 15th century inclusive, some of which were still very black, while others varied from pale yellow to different shades of dark yellowish brown. All the documents he experimented upon, with one exception, agree in the general result, showing that the ink employed in these manuscripts, was of the same nature as that in present use. The letters turned of a reddish or yellowish brown on the application of alkalies; were rendered pale, and at length obliterated, by the dilute mineral acids, and the drop of acid liquor which had extracted a letter changed to a dark blue or green on the addition of a solution of prussiate of potash; moreover, the letters were changed to a deeper tinge by the infusion of galls. Hence he asserts that it was evident one of the ingredients employed was iron, which there was no reason to doubt was joined with vitriolic acid; while the colour of the more perfect manuscripts, which in some was a deep black and in others a purplish black, together with the restitution of that colour, in those which had lost it, by the infusion of galls, sufficiently proves that another of the ingredients was an astringent matter. No trace of a black pigment of any sort was discovered, the drop of acid which had completely extracted a letter appearing of an uniform pale ferruginous colour, without a n atom of black powder or other extraneous matter floating in it. One of the specimens sent to him by Mr. Astle, proved very different from the rest. It was said to be a MS. of the 15th century, and the letters were those of a full engrossing hand, angular, without any fine strokes, broad, and very black, on which none of the above reagents produced any considerable effect; most of them rather seemed to make the letters blacker, probably by cleaning the surface, and the acid, after being rubbed strongly on the letters, did not strike any deeper tinge on testing with the prussiate of potash. Nothing gad any sensible effect, he found, towards obliterating these letters, except what also took off part of teh surface of the vellum, when small rolls, as of a dirty matter, were to be perceived. It is, therefore, unquestionable, he continues to say, that no iron was used in this ink, and, from its resistance to the chemical solvents, as well as a certain dotted appearance in the letters when [] closely, and, in some places, a slight degree of gloss, there was little doubt, in his opinion, that they were formed with a composition of black, sooty, or carbonaceous powder and oil, probably something like our present printer's ink, and, from these results, he was led to suspect that these marks were actually printed. It is said that a subsequent examination proved this to be part of a printed book.

From these experiments, and with the belief on his mind that this latter document must have been printed, he concludes that ancient inks had no carbon in them, and that their greater durability depended upon the better preparation of the parchment or paper upon which the writing was made.  The fact that the tinge of colour produec by the action of prussiate of potash seemed less deep than that produced by its action upon inks of more modern date, led him, also, to belief that there was a less quantity of iron, in proportion to the astringent matter, than is used in the present day. So generally did he believe iron to have been used in the inks of ancient times, that he recommends for general adoption the use of prussiate of potash, combined with a mineral acid for reproducing writings which have been affaced by age. Indeed, in support of the view that iron was generally used in the manufacture of these inks, we find Camparius, who wrote on the subject of inks at Venice, in 1619, recommending the use of an infusion of galls in white wine for the restoration of faded MSS.

Though at first sight the experiments of Dr. Lewis and Mr. Castle seem at variance with those of Sir Charles Blagden, yet, I think, they will both serve to support a view of my own, that the ink of the earlier centuries of the Christian era, no uninorm receipt was adopted, but while in many cases it was purely carbonaceous, yet it generally consisted of a black dye, very similar to our ink, with the further addition of a large quantity of lamp black, or fluely-powdered charcoal. It will be found that neither Lewis nor Astle give us the method of chemical analysis which they adopted, and therefore, we may suppose that with the preconceived notion that the ink was simply carbonaceous matter held in suspension in some mucilaginous fluid, when their experiments proved the presence of pure carbon in the writing, they did not sufficiently prosecute their researches to discover the iron, but decided at once that it was simply what they had previously supposed. Relative to the experiments of Blagden, it must be borne in mind that we do not know on how many specimens he experimented, but we do know that none of them were of earlier date than the ninth century, and, although in some he did not find any trace of carbon, yet in one of them its presence was most clearly proved, and the tests for iron he does not say produced no effects upon it, but no considerable effexts, and with regard to his suspicion that this latter was a printed document, I cannot conceive that he was correct, because, if  so, it must have shown the indentation of the type; moreover, printing was hardly so far advanced at that time as to be such a perfect fac-simile of writing, as to deceive a person of Dr. Blagden's knowledge and research throughout the seires of microscopic investigations which his experiments required. It must be remembered that it was not the appearance of the writing, but the chemical difference of the ink that first led him to suspect that the words were printed and not written.

From experiments I have made with inks composed of black dye and the lightest lamp-black, I find the great obstacle to their use is the difficulty of keeping the carbon in suspension, and knowing when it is so, for, if not frequently agitated, the carbon settles down, and, the colour of the ink not depending upon it, you continue your writing, little thinking that it is quite destitute of the principle upon which its premanence depends. I conceive tit to be possible that in many of the MSS. of former days the writing might be destitute of carbon through the carelessness of the writer in not seeing that the ink was shaken, and I think we may fairly conclude that such was the case with those MSS. in which Dr. Blagden could discover no trace of carbon. Again, if Dr. Lewis and Mr. Astle were correct in saying that all the ink of the earlier ages was composed of lamp-black which never changes it appearance, how are we to account for the various tints of colour which those deeds exhibited. Mr. Astle refers to the following curious case, showing the various changes of tints which the ink of one period has undergone, and it does not seem to have occurred to him that this case militates most strongly against his own opinion. He tells us that he had in his possession a long roll of parchment, at the head of which was a letter that had been carried over the greatest part of England by two devout monks, requesting prayers for Lucia de Vere, Countess of Oxford, a pious lady, who died in 11[28?)] The roll consisted of many skins of parchment and together, all of which, except the first, contained certificates from the different religious houses that the monks had visited them, and that they had ordered prayers to be offered for the Countess, and had entered her name in their bead rolls. He says, "it is observable time had had very different effects on the various inks with which these certificates were written. Some are as black and fresh as if written yesterday, while others are changed brown and some are of a yellow hue."

No, I am inclined most strongly to contend that if those signatures had been made with a purely carbonaceous ink, they could not have changed to a yellow hue, while I do think it, nevertheless, highly probable that in all, or most of them, carbon had been used, although in some cases it might have settled to the bottom, and not been taken up by the pen. Some of the MSS. at the Birtish Museum give remarkable support to my opinion, for on closely inspecting them it will be seen that while some words and letters, even parts of letters, have retained their full depth of blackness, yet the remaining parts of these letters are of a yellowish colour, in some places with black particles in them, and in others without a trace of any black matter, and so regularly does this remarkable change occur throughout some of the MSS., that by noticing where the blackness commences and runs off to pale yellow, you can almost [] out every place where the pen has freshly dipped into the ink, showing beyond a doubt that such writing was done with an iron ink that had free carbon in it, and, through want of care in keeping it agitated, there was not sufficient carbon for it to be distributed through all the letters. The statements of Pliny and Dioscorides also confirm me in my view. Pliny discoursed on so many subjects, of which he had no practical knowledge, that his remarks are often difficult to understand, yet both he and Dioscorides plainly tell us that the Romans and Greeks used inks made otherwise than from lamp-black and charcoal, and, as Dr. Lewis and Mr. Astle, as well as the authors of articles in many of the encyclopedia tell us, that both these ancient writers support their view, that the only inks used in former times were carbonaceous, I will here give the literal translation of their remarks on the subject.

We read in Pliny's natural history, "Atramentus, too, must be reckoned among the artificial colours, although it is derived in two ways from the earth. For sometimes it is found exuding from the earth, like [] of salt pits, while at others an earth itself, of a sulphurous colour, is sought for the purpose. Painters, too, have been known to go so far as to dig up half-charred [bones?] from the sepulchres for this purpose; all these plans, however, are new-fangled and troublesome, for this substances may be prepared in numerous ways from the soot that is yielded by the combustion of resin or pitch, so much so, indeed, that manufactories have been built on the principle of not allowing an escape of the smoke evolved by the process. The most esteemed black, however, that is made in this way, is prepared from the wood of the torch pine. It is adulterated by mixing it with the ordinary soot from furnaces and baths, a substance which is also employed for the purpose of writing. Others again, calcine fried wine lees, and assure us that if the wine was originally of good quality from which the colour is made, it will bear comparison with that of Indicum.

"Polygnotus and Micon, the most celebrated painters from Athens, made their black from grape husks, and called it Triginon. Apelles invented a method of preparing it from burnt ivory, the name given to it being Elephanterion. We have Indicum, also, a substance imported from India, the composition of which is at present unknown to me. Dyers, too, prepare an atramentum from the black inflorescence which adheres to the brazen dye pans. It is made also from the logs of torch pine burnt to charcoal, and pounded in a mortar. The Sepia, too, have a wonderful property of secreting a black fluid, but from this liquid no colour is prepared. The preparation of every kind of atramentum, is completed by exposure to the sun. The black for writing having an admixture of gum, and that for colouring walls an admixture of glue. Black puigment that has been dissolved in vinegar, is not easily effaced by washing."

Dioscorides says, "The ink with which we weite, is composed of the smoke collected from lamps. With a pound of gum they mix three ounces of black. By another process branches or pieces of the torch pine are burnt till they become charcoal, when they are extinguished, then pounded in a mortar, and mixed with glue. These make an ink not unpleasant. A third mode is also taken, that of mixing certain proportions of painter's black, pounded charcoal, glue, and what is termed the flowers of brass, (that is the flosculent substance that forms on the surface of melted copper cooled by water)."

Now, although I have sought to show that in many cases the ink of the ancients was composed of a combination of black dye and lamp-black, yet, we known that in some cases it was simply lamp-black mixed with some viscid substance, as gum water or oil. For instance, we find in the MSS. in the Royal Library at Portici, that the letters are blacker than the papyri upon which they are written, though this is perfectly charred; and thus we know that vitriol could not have been employed in the composition of the ink which was used upon them, or the great heat to which they were exposed would have turned the writing to a yellow tint, by evaporating the acid and leaving the iron in a state of oxyde or common iron rust. Besides, the delicate nature of the papryrus would not have borne the corrosive nature of a vitriolic ink, which would have penetrated through it, as may frequently be observed in later manuscripts written on parchment, a far less delicate substance than the papryrus. These papyri manuscripts were evidently written with an ink made of oil and lamp-black, which must have been very thick, and was probably used with a brush, and any doubts as to its composition were set at rest by the discovery, at Heculaneum, of an inkstand with a small quantity of ink in it, which, upon examination, proved to be merely a thick rich oil mixed with lamp-black. The lamp-black was ground up with the oil as painters' colours are now done, and by remembering this we can understand the meaning of Demosthenes when, in a speech of his, he taunts his great rival, Æschines, for having been compoelled in his youth, through poverty, to sweep the school, sponge the benches, and grind the ink. The description of ink was also, in some cases, un use in the 7th century, which we learn from a description given by Isidorus, of Seville, as to the nature of its manufacture. But the difference of views regarding the composition of these ancient inks has plainly arisen from the idea that all must have been made by some uniform receipt, which was no more probable than that it should be the case in the present day.

From the fact that there appears less change of colour in the documents written prior to the 10th century, I conclude that while in many cases the very early inks were purely carbonaceous, great care being taken in the use of them, yet, that as the art of dyeing became better understood, so the mixture of black dyes with carbon gradually came into use, till at las the trouble attending that made with carbon led gradually to its being less and less adopted, and it was at length entirely discarded, and the ink made simply with the sulphate of iron and gum combined with an astringent, such as galls or logwood. A substitute for ink was obtained by the Africans from the dark fluid which the Sepia or cuttle-fish has the property of ejecting to conceal its retreat when pursued by an enemy. From Persius, when describing the apparatus of the indolent student, using the word sepia for writing, it is probable that though not generally in use amongst the Romans, it was occasionally employed.

Besides black, the ancients used many different colour. Thus, we find the Sacrum Encaustum, a purple ink, the composition of which was kept a profound secret, was employed for signing documents by the Roman emperors, to whose use it was exclusively reserved; and, by an edict of Leo the Great, it was forbidden, under pain of death, to possess, use or even endeavour to obtain it from the vigilant officers in whose custody it was preserved. This edict was in force from A.D. 470 to 1452, except that in the 12th century of privilege of using it was extended to the members of the Imperial Family, and, in some cases, to the great officers of state. Green ink was especially reserved for the signatures of the guardians of the Greek emperors while their wards were minors.

Since the inferiority of modern ink, compared with the ancient, has become known, several parties have directed their attention to its improvement, but I regret to say with as yet very little result. Those only whose researches on this point are really worthy of much attention are Dr. Lewis, published in his work already referred to, and those of Rebaucourt, published in the 12th vol. of the French Annals of Chemistry; but, unfortunately, they arrive at very different conclusions.

Dr. Lewis considers the rapid decay of many modern inks to arise from  a deficiency in the quantity of galls, for, these being perishable, he conceives that the amount which gives the deepest colour at first may be insufficient to maintain it afterwards, and says the great art of making inks is to have a superabundance of astringent matter, so as to counteract the tendency of the iron to oxidation, which is the cause of the ink turning brown and afterwards to a yellow hue, and he recommends that the galls be finely powdered.

Rebaucourt, on the other hand, tells us that none of the principles should be in excess. "For," he says, "if there be more galls than the iron requires, the remainder will be nearl in the state of decoction of galls, subject to change by becoming mouldy, and undergoing an alteration in the wiring which will destroy its legibility much more completely than the change undergone by ink containing too small a proportion of galls; while, on the other hand, if there be  a deficiency of them, part only of the salt of iron is decomposed, and the remaining portion will, by exposure, become oxidised and change its colour." He recommends bruising the galls, and not pounding them, and proposes, in addition to the iron, to use the sulphate of copper; but this, though Pliny and Dioscorides tell us copper was used in former times, has great practical objections in modern days, because, in using steel pens, the metal immediately becomes coated with copper, and the acid, set free, soon corrodes them, and they become brittle and useless, while with quills, the knife used in making them is in like manner covered with copper, and the acid, acting on the steel edge, causes it to require constant sharpening.

But I am convinced there is more to be considered in connection with the permanence of our written documents than merely the composition of the ink which is used upon them, and that there is much truth in the opinion of Sir Charles Blagden, that the permanence of ancient writing greatly arose from the quality of the paper or vellum upon which they were written. The tannic acid formerly retained to a considerable extent in the paper made from linen rags is entirely destroyed by the [] process to which both the linen and the paper are subjected in modern days [- puuttuu toinen palsta, useita kappaleita -]

[---] should make himself thoroughly acquainted with the different sorts, that he may not be imposed upon.

Having, the, carefully chosen the galls, we treat them with distilled water for a few hours, till they are quite soft, and then let the decoction stand for three or four days, when the clear liquid is strained off, and to it is added some of the best gum Senegal. When this is dissolved, we throw into it a quantity of clean iron filings, or several coils of fine iron ware, and agitate several times a day, till the liquid is turned of a deep black. We then draw it on from its sediment, and dissolve in it some pure extract of logwood. In the coarse of the operation [---] upon the iron, considerable effervescence [---] , which is caused hy the decomposition of the  [---]  escaping, and the oxygen forming  [---] an oxide, which the gallic acid in the solution [---]. We prefer this process to that in which  [---] is used, because in the latter the gallic acid  [---]  with the iron, leaves free sulphuric acid [---] which corrodes pens, paper, and parchment,  [---] metal inkstands into which it may  [---]  ink on the prepared paper, the wogwood [---] the state of extracts, combines with the  [---] , and throws down into the  [---] a black precipitate, which, when  [---] against most chemical re-agents.  [---] , while it is jet black at the  [---]  limpid to dow freely in the  [---] the writing, does no become [---] long time, and is, when used on the  [---] . Although I cannot,  [---] the effects of time, yet I  [---] of chlorine makes no [---] precipitate is formed  [---] action of the  [---] will have as little effect  [---] re-agents.

 [---] or writing inks was  [---] by the  [---] James Watt, in 1780.  [---] year, took out a patent of copying letters  [---] . The great objection to oil copying inks has, hitherto, been that their copying properties  [depending?] on the ink not deying quickly and on leaving a considerable quantity of surface in the writing, they could only be used on documents than were to be copied at once, and even these, after a few hours, lost all their copying properties. But the ink made as I suggest, if used on unprepared paper, which dries quickly and leaves no surface on the writing, may at any time after be copied on thin paper prepared with the neutral chromate of potash, and these duplicates as well as the original, when once dry are as proof against chemical re-agents as if the ink had been used on the prepared writing paper. Instead of keeping two inks in the offeice, we propose to have only one, and to write all letters on unprepared paper, taking a copy of them; while all deeds and other paper documents should be written on the prepared paper, which we also make up into account books, and thus we have our papers, books, and letters, all alike proof against the probable effects of time, or any endeavour wilfully to tamper with them.

The attention of myself and partner was called (last March) by the Executive Government of this country, to a requirement for the more rapid and effectual transaction of their business, and which we afterwards found to exist as extensively in the commercial world. Your Society being aware of the want, had, unknown to us, offered a premium, some two or three years back, for the discovery of some expedient to supply this deficiency, requesting the invention of some plan for rapidly taking many copies of written documents. At first, I looked upon the number of copies required by the government as an insurmoutable difficulty, but being much urged by them to make experiments, and remembering that we had overcome the difficulties of making printing inks copyable, to which I shall shortly refer, I resolved to try what could be done. I made, as you may soppose, an immense number of experimetns without success, but at last the idea occurred to me, that by preparing the ink I wrote with, and the paper, with different chemicals having a strong affinity for each other, and which should throw down coloured precipitates, or by chemical reaction change colour wherever they came in contact, I might instead of one take many copies of a document at the same time, and after I had tried many chemicals I found my theory to be correct. The process which gave me most copies was by preparing the tin paper with the neutral chromate of potash, and writing with a strong solution of extract of logwood. Many experiments were required to discover the right strength of the solution of neutral chromate of potash with which the paper is to be prepared, because if I need much of it I could only take one or two copies, as the whole of the extract of logwood would be acted upon by the quantity of the chemical salt in the first sheet or two, therefore to get many copies it is necessary so to reduce the quantity, that while there is enough to have a chemical affinity for the extract, and to change colour whenever it is attracted, it shall not be enough to neutralise the extract until the desired uymber of copies are taken,a nd therefore, instead of having paper prepared with the different quantities of the salt, according to the number of copies required, which would have tended to much confusion in all offices of business, we thought it best to have one standard for the paper, and though we would only keep one ink for letter writing and general purposes, yet we make different qualities of this manifold copying fluid. We have three of these, our No. 1 is the ink formerly noticed as useful for both copying and book purposes, and from which two copies may be taken; our No. 2 has no galls or iron, but is a solution of pure extract of logwood so carefully prepared that exposure to the air in its liquid state shall not have any effect on it, although otherwise it would change in a few months, and from which six or eight copies may be taken at the same time. Another we call No. 3, which is the same, only containing more extract of logwood and which gives twenty to thirty copies, even more if the writing is allowed thoroughly to dry before attempting to copy.

We have also produced an Indian ink on the same principle, which, when used in the preparation of architectural plans, maps, &c., will give one or more clear copies of even the finest lines, and I had hoped to have had specimens of this class of work for your inspection, but the short time I have had for preparation must be my apology for the omission. The only point to be observed in the taking of such copies, is that as they are done to a scale, they must be kept pressed in a close contact with the original, till they are perfectly fry, because if not they will shrink in drying, and the scale be spoilt. While speaking of copying such plans, I may state what, I believe, has never before appeared in print, or been made public, that the ingenious Watt, who invented the plan of copying letters, turned his attention to this point also, and, instead of the ordinary China or Indian ink, used lamp-black rubbed up with the finest and oldest sherry wine, and from plans so made took off a copy on damp paper. From this, which, of  course, was reversed, he could take many copies, by letting a boy overrun each of the lines with a mixture of lamp-black and sherry, and after each time of its being so overrun he could take 4 or 6 copies on damp paper. But though the process is adopted by one or two-engineering houses in the present day, it is very troublesome, and unless very many copies are needed, it has always been found easier to take tracings. But in all architect's and engineer's offices we believe that our process will be adopted and save an immense deal of time and labour.

Relative to printing ink, your time requires that my remarks be comparatively brief. In examining the earliest printed works, one particularly notices, tha twhile the ink used in the first stages of block-printing was of a very inferior sort, yet that which was used in the first works printed from moveable types, was far superior to that in use towards the end of the last and beginning of the present century. The former still retain a depth, brilliancy, and richness of colour, both in the letter-press and illuminated capitals, apparently as perfect as the day they were printed, while in the latter the ink is brown, withered-looking, and destitute of all clear, distinct, and brilliant apprearance.

Within the last few years, however, great improvement has been made in this branch of art, and the best inks of the present day, equal, if not excel those of Caxton and the early printers. For these improvements we are greatly indebted to the chemical knowledge brought to bear upon this branch of manufacture by the Messrs. Flemmings, of Leith, and as they carried off the proze medals for printing inks at both the New York and Paris Exhibitions, I have consulted them, and would here acknowledge their kindness in fully explaining to me the most important points in the manufacture of really good printing ink.

We will first consider the necessary qualifications for it, and then see how best to attain these.

1st. It must distribute freely and easily, and work sharp and clean.

2nd. It must not have too great tenacity for the type, but have a much greater affinity for the paper, and so come off freely upon it.

3rdly. It must dry almost immediately on the paper but not dry at all on the type or rollers; this is a great desideratum especially for newspapers; this drying should be so rapid, that the sheets on being delivered from the machine, will allow the thumb nail to be drawn swiftly over the surface of the newly printed matter without smearing; and though this constant dring on the paper and never drying on the roller or type seems a contradiction and absurdity, yet it is one of the easiest points to be obtained if the manufacturer has any chemical knowledge, and if he is destitute of this it will be in vain for him to attempt to perfect the ink in this respect.

4th. It should be literally proof agains the effects of time and chemical re-agents, and never change its colour.

To attain these objects, great experience, and care are required in the purchase of the raw materials. Of one of these, linseed, there are many varieties, the Baltic, Black Sea, and East Indian, each yielding oil very materially different, the one kind giving by pressure a thin limpid oil, another a thick mucilaginous oil, which produce very different results under the same application of temperature. The ink-maker having, then, tried his seed previous to purchase, to see that it yields the best oil, must be careful in its mode of crushing, and should only use the oil which comes from the first crushing, because the increase of pressure, after the first oil has been expressed, or the method of steaming the seed and crushing again, gives an additional quantity of fatty matter, which spoils the ink, and which, when present in large quantities, cannot be effectually extracted.

The oil is now clarified from the fatty matters, which will come away, even with the first pressing, and the pure oil is then boiled with great care, regulating the temperature with thermometers, and when in a proper state, the best pale yellow soap is added, to give it consistency. During the boiling, the dryers are added with great care, the proportion varying with the strenght of the varnish required. The soap should be previously tested, and the ingredients known. the boiled oil, with these additions, becomes a varnish. In the making of ink for some of the finer descriptions of book-work, palm oil and cocoa-nut oil are valuable additions.

The next point is the manufacture of the blacks, which is a far more scientific operation than one would at first imagine. The finest naptha only, very carefully rectified, should be used, and on burning it the application of oxygen must be regulated to the combustion otherwise the sudden expansion of the gases will [---]  would cause a serioys explosion [---] [loppukappale lukukelvoton]

Relative to this blue, I would advise the manufacturer to see that his prussiate of potash, nitro-muriate of iron, and acids, are chemically pure, and to use leaden or enamel boilers, instead of the iron ones which they too generally employ. These should be heated by steam passing through leaden or enamelled tubes, as the brightness of the colour depends entirely on chemical purity. Ink made upon this plan, while doubtless the best for book purposes, does not answer for many of the requirements of commerce, and some of the railway companies and large mercantile firms have long been anxious to obtain ink capable of having copies taken from it by the ordinary copying press. This difficulty we have, at least, got over, by using a deep-coloured varnish, which will freely dissolve in water, instead of the oily one just described, with which we grind our black, or, if we desire more htan one duplicate, using a chemical in it such as logwood, and taking our copies on the prepared copying paper, regulating the proportions of logwood to the number of copies required. These copies, with the original, being based on the same principles as our plan of taking duplicates of written documents, are, like them, proof against chemical re-agents, or the probable effects of time.

I had proposed to have explained how, by varying the chemicals used, the same principles may be carried out to take manifold coloured copies of draqings, paintings, &c., but time forbids, I trust, however, I have succeeded in stirring up inquiry on this subject, and in showing you that it is possible to have our writings as lasting as those of ancient days, and  that our plan of taking multiplied copies of written and printed documents is very simple, and of no small literary and commercial value.



The CHAIRMAN said that it now became his duty to invite discussion on the subject opened up by the paper of Mr. Underwood, which was one of great commercial and economic importance, as well to the professional and literary world as to merchants, bankers, and traders. The statement which they had heard, and in which was traced the history of the art of writing and of the materials employed, from the earlierst times, through the middle ages, when the chief scribes were monks and friars, down to our own times, was replete with interest, and did credit to the research of the author of the paper. The Society was favoured that evening with the attendance of many gentlemen who, from their scientific and professional knowledge were eminently competent to discuss the subject. His friend Mr. Deputy Lott, for instance, was not only a solicitor, and therefore interested in the success of Mr. Underwoodäs invention, but, being an active member of the Antiquarian Society, he was always alive to the progress of antiquarian research, and the citizens of London were largely indebted to him for the preservation of many important specimens of ancient architecture. He begged therefore to invite Mr. Lott and other gentlemen to join in the discussion.

Mr. Deputy Lorr said the importance of this subject [---] be overrated. He felt an interest in it, [---] six or seven years ago, when he had the honour[---] in the Council of the Society, he induced his [---] a premium for a process of copying [---] superior to any that was then in use. As a [---] it to be a matter of immense importance, [---] what had been stated by the author of the ppaer, he was still of opinion that, up to the present time, the inventions that had been brought out [---] them producing results so satisfactory as he [---] . As far as he was aware, there were only two principles which had been practically carried out in the copying processes hitherto used; one of them had been [---] by Mr. Underwood, and he (Mr. Lott), could [---] hope that the process described was an improvement in what had hitherto been done, Still, however, it was too often found in practice - whether from the [---]  of the ink or the paper he could not say - that the [---]  half the original, or that in the lapse of three or four years the document was not in a state to be produced in a court of justice as an authentic copy. It was of the greatest importance in his own profession that documents should be capable of verification beyond all dispute, but as far as he was acquainted with what had been accomplished up to this time, he was sorry to say, the objections he had stated had not been removed. The other mode of copying was that known as the manifold writer, and this he thought by no means satisfactory, and the writing with the stule, was much objected to. With reference to the mode of copying introduced by Mr. Underwood the results certainly appeared, judging from the specimens exhibited, fairly successful. Still he (Mr. Lott) thought much remained to be done in that direction. The specimen which he had examined was somewhat imperfect, and appeared to be fading; but the scientific investigations which had been made into the question would probably ultimately lead to these defects being obviated. The author of the paper had dwelt upon the superiority of the inks used in former times. In illustration of that he would mention that he had seen in Durham Cathedral a copy of the Scriptures transcribed by the Venerable Bede, in which the ink used must have been of the very best description, inasmuch as at this distant period the writing was perfect, and the ink a beautiful black. Some years ago he laid upon the table of the Antiquarian Society a grant from the crown, signed by Queen Katherine as regent of the kingdom, during the temporary absence of Henry VIII, at the Field of the Cloth of Gold. It was the most beautiful specimen of writing he had ever seen, and the ink was a perfect black. There was another method of coping to which he would advert, in which the sun was the agent - be alluded to photography; having seen wonderful reproductions of the title pages of books as well as MSS., he thought that its application might be extended to more useful and practical purposes. If this agent could be brought into general use it would prove a very great desideratum to the members of his own profession, as he believed, by that means, a perfect copy of a MS. could be secured.

Mr. CHARLES MAY said, this was a subject which had occupied much of his attention for many years. In the early transaction of the Society, there was to be seen a copy of the specification of James Watt, for an ink for copying purposes, and the mode of preparation was described. The paper upon which the copy was taken was prepared with a weak solution of galls. He had seen copies of MSS. in the possession of the present firm of James Watt and Co., which had been in existence for upwards of 70 years, and which, although they had lost their pristine blackness, were nevertheless perfectly legible, owing to the quantity of oxyde of iron deposited upon the paper by the ink employed. He (Mr. May) was inclined to believe that no preparation of vegetable acids, in combination with iron, would for any great length of time retain its blackness, so long as paper bleached with chlorine was used. It was to this curcumstance that he chiefly attributed the marked difference which was observable between the state of preservation of the colour of ink in ancient and modern MSS., rather than to any special difference in the ingredients of the ink itself. With reference to the periods of time at which written documents could be copied, he would mention that for some years he used in his business transactions Arnold's ink, and he could obtain a distinct copy from that three weeks after it was written. It was not a pleasant coloured ink in the first using, being very dull, but it afterwards became a good black. With a little management three or four copies could be taken. He was rather surprised that Mr. Underwood had not referred to the use of indigo in inks. Indigo was capable of preparation for such purposes, and the blue inks of the present day, he believed, consisted of indigo, partly deoxydised, so as to become soluble with an admixture of a small proportion of gallic acid and iron. This had the effect of producing a black colour after some time, and from that description of ink he thought several copies could be taken. With reference to the use of logwood, he very much doubted whether any preparation of this substance would be permanent. It was a most beautiful dye, being the chief ingredient in the dyeing of beaver hats, but it was invariably found that exposure to sea air turned them brown, and he had great doubts as to the propriety of using vegetable matter as the basis of an ink in which permanence of colour was a consideration, especially when employed on paper bleached with chlorine, which he believed could not be effectually got rid of by any amount of washing. The subject was one of great importance, and he agreed with Mr. Lott as to the great desirability of securing copies of documents which could be authenticated in courts of justice. He believed that much of the fading of documents copied by the ordinary process was caused by want of attention of the part of the clerks entrusted with the work. The copies were not taken so well as might be done even with the present appliances. The great object to be attained in all copying processes was an uniform dampness, without a surcharge of water in the paper. He would mention that inks which through age had become of a yellow tint, might be restored to blackness by the use of gallic acid; but this fact was frequently observable, - that the iron held in solution in the ink penetrated the fibres of the paper, and distributed itself beyond the line described by the pen; therefore, if the copy was taken upon paper too much damped (and perhaps the book being shut up damp), the iron constituent of teh ink travelled out of its line, and when such writing was restored by the use of gallic acid, much confusion was the result.

Mr. CORNELIUS WALFORD remarked upon the carelessness wirth which copies of letters, &c., were at present taken. He believed, with ordinary precautions, the present process would be found to be all that was required.

Mr. STEPHENS, as a manufacturer of inks, and having extensively experimented on this subject, would refer to the use of chromate of potash in the preparation of paper, as referred to by Mr. Underwood. Some years ago, he (Mr. Stephens) introduced a marking ink, the preparation for which upon linen consisted of neutral chromate of potash. It had been found necessary that the chromate should be removed by washing after the linen was marked, and in such cases the results had been satisfactory; but, having exported a quantity of his marking ink to America, he had received a demand for compensation for linen destroyed through the use of his marking ink. The fact was, that, in the instance referred to, the chromate had not been washed out after marking. The redult was the destruction of that portion of the linen to which the chromate had been applied. Mr. Stephens proceeded to state his experience in the use of indigo as a constituent of writing ink, the indigo being chemically prepared so as to render it more soluble, and the results of experiments, both as to moisture and exporusre to sea ard, had proved the durability of that description of ink. Ink with a vegetable basis had a tendency to decay, which was apparent even when it was kept in bottles. He thought ink made with prussiate of iron was more permanent. When first used, the wiring was of a pale colour, which, upon withdfrawal from the light, became more intense. Mr. Stephes mentioned the results of several experiments with this material, and observed that although prejudice against coloured inks had gone to such an extent that an American judge refused to regocnize documents written in bule ink, yet he hoped such an objection would not be allowed to operate against that which had been found to be of practical utility.

Mr. PEARSALL, without wishing in the last degree to detract from the merits of any invention, would state that, in his own experience, he had found that blue ink was obliterated from the accidental spilling of water over  a sheet written upon with it. If that had been the experience of American judges, he could account for their objection to that description of ink.

Mr. STEPHENS remarked that this would not be the case with documents which had been written for any length of time.

Mr. RUDOLPH APPEL, the inventor of the anastatic and Appelotype processes, stated, that having for twenty-eight years been engaged in transferring printed and written documents of all kinds, and in multiplying copies of them, he might fairly be presumed to know something of the subject then under discussion. About thirteen years since he exhibited to the members of the Society of Arts his anastatic process, when the chairman and various members of the Society wrote their signatures and some sentences, which were transferred, and very many copies worked therefrom within ten minutes, or thereabouts, in each case; and he further stated, that the anastatic process, unlike Mr. Underwood's, was capable of producing any number of perfect copies with a very small amount of labour, occupying only a few minutes in transferring, when the original had been recently written. He was able to reproduce drawings, maps, engineering and architectural plans, with the same facility as common writing, and he had succeeded in reproducing the finest impressions from engraved copper-plates, which had been printed from 50 to 70 years. Mr. Appel instanced the reproduction of the great Austian maps of Russia and Turkey, occupying an area of about 60 square feet; these he was employed by the English government t oreproduce and print at the beginning of the Russian war, and he then delivered fifty perfect copies of each of these great maps within a fortnight. The anastatic process was daily employed at Aldershot and other similar establishments, for the circulation of general orders and official instructions, as well as in the Privy Council Office and other government departments. He thought Mr. Underwood's process was only applicable for producing a small number of copies; certainly, if the vegetable ink made accordinig to Mr. Underwood's method, was found in practice to be permanent, there was no doubt it would be a great improvement, but from his (Mr. Appel's) experience tin the manufacture of inks, he was unable to agree with the author of the paper in the conclusions to which he had arrived; still he thought there were many purposes to which Mr. Underwood's process might be applicable.

Mr. VAUGHAN PRANCE begged to ask what had been the results of the application of Mr. Underwood's plan to the purposes of railway companies, such as the copying of way-bills, &c.

Mr. LAWRENCE wished to ask the lecturer whether he used the ordinary press for copying by his process, and whether the copying ink would serve for ordinary writing, as the copying ink in ordinary use was not adapted for general purposes.

Mr. UNDERWOOD replied in the affirmative.

[loput artikkelista puuttuu]

Ei kommentteja :