Part 19

We have evidence every day in our fruit shops, that in certain countries this kind of earth is yet employed for closing up jars of dried fruits brought from Oporto, Smyrna, and other countries; as these appear to be composed of white chalk of a texture somewhat similar to common mortar. The warmth of the atmosphere, where it is used, soon hardens and prevents the passage of air to the contents; the jars themselves being oftentimes only dried in the sun.

Thus it appears that prepared earths were first used for the purpose of sealing; their adhesive, or, as Virgil has it, their tenacious qualities, being wonderfully improved for manual labour. Next, paste was employed, prepared from dough.

To paste succeeded common wax, sometimes slightly tinctured with a green tint, the effect of endeavouring to give it a blue colour, as vegetable blues turn green by the process of heat employed in melting; whilst mineral or earthy blues all sink to the bottom, from superior gravity. This was the material employed in sealing public acts in England, as early as the fifteenth century. We have an anecdote of the Duke of Lancaster having no seal to ratify a deed between him and the Duke of Burgoyne, but from what appears in the attestation, which, with the instrument itself, according to the general custom of the day, runs in rhyme thus:

“I, John of Gaunt, Doe gyve and do graunt, To John of Burgoyne And the heire of his loyne Sutton and Putton Untill the world’s rotten.”

The attestation runs thus:

“There being no seal within the roof, In sooth, I seal it wyth my tooth.”

A good example is this of the simple brevity of the time, and a severe lecture upon the eternal repetitions of our modern lawyers, whereby the limitations and special uses of deeds are made, perhaps, not according to the necessities of the case, but are lengthened from selfish purposes.

The Great Charter, which gives an assurance of the rights of Englishmen, is sealed with white wax; as may be seen in the British Museum.

The first arms used as a seal in England, were those of the tyrannical subjugator of English rights, William, commonly called the Conqueror, and they were brought from Normandy.

Although Fenn, in his collection of original Letters of the last half of the fifteenth century, published in London, 1787, has given the size and shape of the seals, he does not apprise us of what substance they were composed. Respecting a letter of 1455, he says only, that “the seal is of red wax,” by which, it is presumed, he means common wax; and though, perhaps not equal in quality to such as is now used, yet it was made of nearly similar materials. Tavernier, in his Travels, says, that in Surat gum-lac is melted and formed into sticks, like sealing-wax. Wecker also gives directions to make an impression with calcined gypsum and a solution of gum or isinglass. Porta, likewise, knew that this might be done, and, perhaps, to greater perfection with amalgam of quicksilver.

Among the records of the Landgrave of Hesse-Cassel, are some letters of 1563, sealed with red and black wax. In the family of the Rhingrave, Philip Francis von Daun, the oldest letter sealed with wax, known in Germany, is found, of the date of August 3, 1554; it was written from London, by an agent of that family, of the name of Gerrard Herman. The colour of the wax is dark red, and very shining.

The oldest recipe known in Germany for making sealing-wax, was found by M. Von Murr, in a work by Samuel Zimmerman, citizen of Augsburg, published in 1759. The copy in the library of the university of Gottingen is signed by the author himself.--“To make hard sealing-wax, called Spanish wax, with which, if letters be sealed, they cannot be opened without breaking the seal; take beautiful clear resin, the whitest you can procure, and melt it over a slow coal fire. When it is properly melted, take it from the fire, and for every pound of resin, add two ounces of cinnabar, pounded very fine, stirring it about. Then let the whole cool, or pour it into cold water. Thus you will have beautiful red sealing-wax.

“If you are desirous of having black wax, add lamp-black to it. With smalt or azure, you may make blue: with white-lead, white; and with orpiment, yellow.

“If, instead of resin, you melt purified turpentine in a glass vessel, and give it any colour you choose, you will have a harder kind of sealing-wax, and not so brittle as the former.”

It may be remarked, that in these recipes for the fabrication of sealing-wax there is no mention of gum-lac, which is known at present as a chief ingredient in the composition of this article.

Zimmerman’s sealing-wax approaches very near to the quality of that known as _maltha_, whence we may conclude, that the manufacture of it did not originally come from the East Indies. The most ancient mention of sealing-wax occurs in a botanical work, treating of the history of aromatics and simples, by Garcia ab Horto, published at Antwerp in 1563, where the author, speaking of gum-lac says, that those sticks used for sealing letters are made of it; at which time sealing-wax was common among the Portuguese, and has since been manufactured chiefly in Holland.

M. Spiess, principal keeper of the Records at Plessenberg, says, respecting the antiquity of _Wafers_, in Germany, that the most ancient use of them he has known, occurs in a letter written by D. Krapf, at Spires, in 1624, to the government of Bayreuth.--The same authority informs us that some years after, the Brandenburg factor at Nuremberg sent such wafers to a bailiff, at Osternohe. During the whole of the seventeenth century, wafers were not used in the Chancery at Brandenburg, and only by private persons there.

Seals, it appears, from certain passages of Egyptian history, parallel with, and perhaps anterior to the Israelitish ingress, were formed or cut in emeralds, the native produce of that country. Other precious stones, metals, steel, lead, and a variety of materials, but chiefly of a hard and precious kind, have been always employed for that purpose.

BLACK-LEAD PENCILS.

The period when this semi-metallic substance was introduced, for the purpose for which it is now applied, cannot with certainty be ascertained, as no record is found of the transaction: by the common expedient of inference, however, we certainly may conclude, it was in very remote ages; for transcribers of MSS. upwards of one thousand years ago, used a substance somewhat resembling it in effect.

But, perhaps, the antiquity of the use of black-lead pencils cannot be so well determined from diplomatiques, as their frequency might be proved from mineralogical writers. The first mention of this discovery occurs in the works of Gesner, who, in his “Book of Fossils,” published in 1565, says that the British people had pencils for writing, with wooden-handles inclosing a piece of lead, which he believed to be an artificial composition; and it was called _stimmi Anglicanum_; which seems to import that it was a British production; and we should consider, from the name of British antimony being given to it, that it might have been Cumberland black-lead.

About thirty years afterwards, Cæsalpinus gave a more perfect account of it:--he says it was a lead-coloured, shining stone, as smooth as glass, and appeared as if rubbed over with oil; it gave to the fingers an ash-grey tint, with a plumbeous brightness; and, he adds, pointed pencils were made of it, for the use of painters and draughtsmen. A closer description of the substance than this cannot be discovered.

Somewhere about three years afterwards, a still more perfect description was furnished by Imperatis; who says, “It is much more convenient for drawing than pen and ink, because the marks made with it appear distinct upon a white ground, also, in consequence of its brightness, show themselves on black, and can be preserved or rubbed out at pleasure. This mineral is smooth, appears greasy to the touch, and has a leaden-colour, which it communicates with a metallic brightness. It can resist, for a long time, the strongest fire, and even from it requires more hardness; it has, in consequence, been thought to be a species of _talc_. This, in the arts to which it is applied, is a property which greatly enhanceth its value, being manufactured into crucibles, &c., with clay. These vessels are capable of enduring the strongest heat of a chemical furnace.”

Sometimes this lead is foliaceous, and may be crumbled into small pieces or scales; but frequently found denser and more strong. This latter is what writing pencils should be made of; but the former being more frequently found, and, also, coming from the refuse of the workmen, is too often mixed up with some glutinous substance, and there is every reason to suppose it to be enclosed in the groove in a plastic state; these pencils are commonly hawked about our streets by pedlars and Jews; of purchasing which people should be cautious, as they are, in general, utterly worthless.

Robinson, in his Essay towards a natural History of Westmoreland and Cumberland states, that, at first, the country people round Keswick marked their sheep with black-lead. Afterwards, they discovered the art of employing it in their earthenware, and also to preserve iron from rust. The same writer says, the Dutch use it in dyeing, to render black more durable; and that they buy it in large quantities for that purpose. But their application of it for dyeing, we should consider as highly questionable.

The mode of eradicating black-lead by means of an elastic gum, called caoutchouc, or, Indian-rubber, was, we have been informed, first discovered in England somewhere about sixty years ago.

COLOURED GLASS.

The manufacture of glass we find was quite common in Ethiopia, Syria, Assyria, and other Eastern countries, in the earliest ages of the world, as Diodorus Siculus informs us, who says, the Ethiopians enclosed in glass, the bodies of their parents and friends; we doubt, however, that on this point, the historian was deceived. But it really appears probable that soon after the art of making glass was discovered, the idea of communicating to it some colours would easily present itself. This probability appears increased, when it is recollected that much care is requisite to render glass perfectly colourless. As the various metallic particles with which stone and sand abound, (these being the chief ingredients of which glass is composed, and which gradually give tints in fusion,) will almost unavoidably communicate some hue or other, therefore the perfection of glass is to have it perfectly colourless.

But with respect to coloured glass; so frequently have people been imposed upon by having coloured glass sold to them for valuable stones, that some conscientious authors have very laudably and carefully abstained from lending the benefit of instruction in its manufacture, by publishing the method.

The Egyptian artists were so famous in the manufacture of glass, that the Romans were content to receive this article from the glass-houses in Alexandria, and did not interfere in endeavouring to procure the art themselves, until the latter part of the empire.

We read that an Egyptian priest made a present to the Emperor Adrian of several beautiful glass cups, which sparkled with many colours; and such value did that august personage place upon these toys, that he ordered them to be used only on high feasts and solemnities.

Strabo relates, that a glass manufacturer of Alexandria informed him that an earth was found in Egypt, without which the valuable coloured glass could not be made. It has been thought by some, the glass earth here meant was a mineral alkali which was readily found in Egypt, serving to make glass; but this author speaking expressly of coloured glass, it has been suggested as probable, the alkali above named could not have reference to what the artisan intended to imply, but that it must be referred to some metallic earth or manganese.

One Democritus is named by Seneca, as having discovered an art of making artificial emeralds; but it has been conjectured that what the philosopher meant was the art of communicating colour to natural rock crystal, or colouring glass already made, so as to resemble stones, which is a process performed by cementation. Directions have been furnished for this purpose by Porta, Neri, and others; but it is discovered that the articles so coloured are liable to such accidents in the process, that it is next to impossible to render things of any size tolerably perfect, so as to bear cutting afterwards.

In the Museum Victorium at Rome, there are shown a chrysolite and an emerald, both perfectly well executed, and thoroughly transparent, without a blemish.

We have not from the ancients an account of what process they employed; but it must be evident that nothing less than metallic calces could have been used; and for this evident reason, that any other substance could not have resisted the influence of the necessary heat. The last century has, however, produced certain artists in northern European nations, who have adopted a method of employing the precious metals, to communicate a tincture to glass in the process of making, where iron, &c. were originally only used; and their endeavours have been attended with singular success.

By means of an amalgam of gold, or a solution in _aqua regia_, and precipitated with a solution of tin, the metal then assuming the appearance of a rich purple coloured powder; so prepared, it is mixed with the best _frit_, and then called the precipitate or gold calx of Cassius, the inventor of gold purple, or mineral purple.

This precipitate communicates a rich ruby coloured purple, so perfect that it is impossible to discover the deception, without the substances be tried by the usual means--cut with a diamond or a prepared file.

We have had in England some very eminent artists in the practice of staining glass, and also for making artificial representations of various precious stones.

Although the professed object of alchemy has now met with that contempt it merited--because, notwithstanding the immense sums which have been expended, the time lost, and unprofitable labour employed in the unavailing search after what probably never will be found--yet the labour lost and money expended has not been totally useless, since it has served to open the seals which secured chemical science to the modern world; and which is the chief, if not the sole advantage it can claim over antiquity for superiority of information.

Painting on glass, but, perhaps, staining had been a more appropriate expression, or, properly speaking, in enamel, with the preparations for colouring in mosaic work, may, to a certain extent, be justly considered as branches of the art of colouring glass; in all which there is no colour more difficult to be attained than a beautiful red; it now is, and ever has been, most difficult, consequently the dearest colour. The presumed ignorance of ancient artists in preparing this colour has afforded some reason, it is said, to suppose the ancients knew of no other substance proper for that purpose but calx of iron, or manganese. To this we may reply, many specimens are found which show they were not so ignorant in that art, and that it is more than probable the same jealousy which is found to exist in modern days among artizans might prevent our sagacious predecessors from publishing the secrets of their respective professions to the world. We contend, that as the materials must then have had existence, which have been since so successfully employed, pray what was the reason the ancients should not avail themselves of their benefit? In all the higher speculations of science and arts, where the great and superior energies of genius were requisite, this perfection in the ancients far surpassed any exertions which have been since achieved by the moderns. To instance one artist and one art solely, we name the great Praxiteles, so famous in the art of statuary, whose works were a model of perfection.

ETCHING ON GLASS AND GLASS CUTTING.

Without entering into the history of the lapidary’s art, we only propose to speak of those things which ancient and modern authors have said upon the art of engraving on glass, observing, that it was an art anciently known to both the Greeks and Romans; although it appears extremely probable, that from their expressed ignorance of many of those properties which modern chemistry has discovered to belong to matter, they were ignorant of the art of etching on glass.

From antique specimens still preserved, a doubt cannot for a moment be suffered to exist on our minds, but that the art of engraving upon glass was familiar to the Greek artists, who formed upon glass both linear figures, and in relievo, by the same means as are now employed for nearly the same purpose, if we can place any confidence in an able and learned lapidary, Natter, who has established, that the ancients employed the same kind of instruments for this purpose, or nearly such as are now in use; abating, perhaps the use of diamonds, and the dust of that precious material, for which it is conceived they used emery powder, and the dust of glass.

From what is related by Pliny, it certainly appears that they used the lapidary’s wheel, an instrument moving in a horizontal direction over the work-table.

Some have thought that drinking cups and vessels may have been formed from the glass whilst in a state of fusion, by means of this wheel; to this they think those words of Martial refer, where he says, _calices audaces_, having reference to the boldness of the artisan’s touch; those vessels he was constructing often broke under the last touch he bestowed upon his transparent labours, although, perhaps, of costly value; these accidents must of necessity have rendered those articles extremely expensive.

There are not wanting many who affirm the art of glass-cutting, with the instruments necessary for that operation, to be of modern invention. Those assign it to the ingenuity of Caspar Lehmann, originally an engraver on iron and steel, and who, as Beckmann informs us, made an attempt, which succeeded, in cutting crystal, and afterwards glass in the same manner. This artist, we are told, was in the service of Rodolphus, the second emperor of that name, who, in the year 1609, besides giving him valuable presents, conferred on him the title of lapidary and glass-cutter to his court, and gave him a patent, allowing him the exclusive privilege of exercising this new art. He worked at Prague, where he had an assistant of the name of Zacharias Belzer; but George Schwanhard, one of his pupils, carried on the business to a much larger extent. The last named was a son of Hans Schwanhard, a joiner at Rothenburg, and was born in 1601; at the age of seventeen he went to Prague, to learn the art of cutting glass from Lehmann. His good behaviour won so much upon the affections of his master, that on his death in the year 1622, he left him his heir. Schwanhard succeeded in obtaining a continuation of the patent from the emperor, and removed to Nuremburg, where he wrought for many of the nobility of that district. This was, we believe, the occasion of that city claiming the honour of being the birth-place of this new art. In the year 1652, he worked at Prague, and also at Ratisbon, by command of the Emperor Ferdinand III.; and he died in 1676. He left two sons, who both followed the lucrative employment of their father. Afterwards Nuremburg produced many expert masters in the art, who, from the improvement in the tools, and also from discovering more economical modes of using them, were enabled to execute the orders of the public at a more moderate rate than had been previously charged for some articles. Those latter masters likewise brought this art to a much greater degree of perfection. Notwithstanding Zahn was of the same country, and must have been apprised of the facts previously stated, yet he mentions it as a very recent invention at Nuremberg, at the time he published his “Oculus Artificial.” He also furnishes a plate, giving at the same time a description of the various instruments employed. However, that this invention is not purely _novel_, may be perceived from those facts we have already submitted.

It should be stated that before this latter re-introduction, artists used, with a diamond, to cut figures upon glass in almost every form, as far as the representation by lines went. The history of diamonds has been presented to the public by Mr. Mawe, in his observations on the diamond districts of Brazil. It appears to be yet undetermined whether the ancients used that stone for the purpose of cutting others; upon this point Pliny appears to be satisfied that they did.

Solinus and Isidore both express themselves in a manner the reverse. But although this may leave us in some doubt, it appears pretty clear that they did not attempt to cut that valuable production with its own dust, or to give it different faces, or render it more brilliant by the same means. If this point was settled, there could be no great difficulty in affirming or negativing the fact of their engraving upon that stone. Thus doubts appear to increase on this head, for Mariette denies that they did; Natter appears uncertain; and Klotz asserts with confidence it was certain. His authority, to be sure, has been considered not to be of much weight.

The proper question, however, appears to be, whether the Greeks and Romans used diamonds for cutting and engraving other stones or glass. Natter, in his work already noticed, thinks they were employed on some antique engravings. His authority is deserving respect. But if they were employed on other stones, the authority which at present directs us, confidently alleges they did not employ them in cutting glass; but he points out the mode in which that article was wont to be divided, in the following terms: “They used for that purpose emery, sharp-pointed instruments of the hardest steel, and a red-hot iron, by which they directed the rents at their pleasure.”

The first mention which appears to occur of the use of the diamond for this purpose, is recorded of Francis I. of France, who, fond of the arts, sciences, and new inventions, wrote a couple of lines with a diamond, on a pane of glass in the Castle of Chambord, to let Anne de Pisseleu, Duchess of Estampes, know that he was jealous.

About 1652, festoons and other ornaments, cut with a diamond, were made on Venetian glasses; then considered the best. Schwanhard was a professed adept in that art; and since his time an artist of the name of John Rost, of Augsburg, cut some drinking glasses, which were purchased by the Emperor Charles VI., at an extravagant price.

ETCHING ON GLASS.

An acid to dissolve siliceous earth was discovered as late as 1771, by the celebrated chemist Scheele, in _sparry fluor_. It is conceived that this cannot be of older date than that period; but it is alleged that an acid was discovered as early as the year 1670, by Henry Schwanhard. It being said that some aquafortis had dropped, by accident upon his spectacles, the glass being corroded by it, he thence learned to improve the liquid that he could etch figures and write upon glass. How he prepared this liquid is a secret which has not been revealed. The _Teutsche Akedemie_ says on this subject, that he, by the acuteness of his genius, proved that which had been considered impossible could be accomplished; and found out a corrosive so powerful that the hardest crystal glass, which had hitherto withstood the force of the strongest spirits, was obliged to yield to it, as well as metals and stones. By these means he delineated and etched, on glass, figures of men, in various situations, animals and plants, in a manner perfectly natural, and brought them to the highest perfection.