ARTIFICIAL DIAMONDS.

We find a report in French journals that M. Gannal has succeeded in obtaining crystals, having all the property of the diamond, through the mutual reaction of phosphorus water and bisulphide of carbon upon each other for the space of fifteen weeks.

The crystals were found to be so hard that no file would act upon them. They cut glass like ordinary diamonds, and scratched the hardest steel. In brilliancy and transparency they were in no way inferior to the best jewels, and some possessed a lustre surpassing that of most real stones.

For reference we record the cost of materials for flint-glass, say in 1840 to 1845, as follows:—

Litherage, or red lead, cost6½cts. per lb.
Pearlash,6 " "
Nitre,6 " "
Silex,0½" "

Present price, 1864:—

Red lead,21 cts. per lb.
Pearlash,17 " "
Nitre,6 " "
Silex,0¾" "

We now refer to the early introduction of the manufacture of glass into England. The English manufacturers, like ourselves, had to struggle with the various evils incident to the introduction of a new art. France and Germany, from their long experience in the making of glass, were enabled for a long time to undersell the English manufacturer in his own market.

To foster and protect this branch of national industry, the English government imposed a heavy tax on all foreign glass imported into their dominions. This measure secured to the English manufacturer the entire trade, both with their colonies and with the home market, thus giving such substantial encouragement to the enterprise, that, in a few years, the manufacture was so much increased as to admit of exportation.

To stimulate the exportation of various articles of English production, the government, in the latter part of the eighteenth century, granted bounties, from time to time, on linens, printed cottons, glass, &c, &c. Until the bounty on glass was allowed, the exportation of glass from England to foreign countries was very limited; for the French and Germans, as has before been stated, for various reasons could undersell the English; but the government bounty changed the aspect of affairs, and shortly the English manufacturers not only competed with the Germans and French for the foreign market, but actually excluded them from any participation,—the government bounty being equal to one half the actual cost of the glass exported.

An Act of Parliament levied on flint-glass an excise duty of ninety-eight shillings sterling on all glass made in England, which excise was paid by the manufacturer, being about twenty-five cents per pound weight, without regard to quality; but if such glass was exported, the excise officer repaid the tax which it was presumed the manufacturers had paid, and a clear bounty of twenty-one shillings sterling was paid by the government to the exporter on each hundred weight of flint-glass shipped from England, being equal to five cents per pound. Under such encouragement the export increased from year to year to a very great extent, so that the excise duty of ninety-eight shillings sterling on the amount consumed at home did not equal the amount paid out in bounty. In the year 1812, fifty-second George III., an Act was passed reducing the excise duty to forty-nine shillings, and the export bounty to ten shillings sixpence. In 1815 the Act was renewed, and again in 1816. In 1825, sixth George IV. chap. 117, an Act was passed revising the former as to the mode of levying the excise duty and bounty, so as to prevent frauds on the revenue, which had hitherto been practised to a very great extent. This act remained in force until the Premiership of Sir Robert Peel, when both excise and bounty were abrogated, and the English manufacture stands on the same footing in foreign countries as those of other nations. By the protecting hand of the English government the flint-glass manufactories multiplied with very great rapidity, underselling all other nations, and not only rivalling, but far excelling them in the beauty, brilliancy, and density of the articles manufactured.

The greatest stimulus ever given to the glass manufacture of England was the abolition of the duty on it in 1845. That abolition has produced a somewhat paradoxical result. While the quantity of glass made has increased in the proportion of three to one, the number of manufacturing firms has diminished in the proportion of one to two. In 1844 there were fourteen companies engaged in the manufacture. In 1846 and 1847, following the repeal of the duty, the number had increased to twenty-four. The glass trade, after the removal of the heavy burden imposed upon it, seemed to offer a fair opening for money seeking investment. The demand for glass was so great that the manufacturers were in despair. Glass-houses sprang up like mushrooms. Joint-stock companies were established to satisfy the universal craving for window-panes. And what was the result? Of the four-and-twenty companies existing in the year 1847, there were left, in 1854, but ten. At this time there are but seven in the whole United Kingdom. Two established in Ireland have ceased to exist. In Scotland, the Dumbarton Works, once famous, were closed in 1831, by the death of one of the partners, afterwards reopened, and again closed. The seven now existing are all English.

The manufacture of the finer kinds of glass was introduced into England not many years ago from Germany, and German operatives were employed at very high wages. We understand that the English glass is now superior to the German.

There is only one plate-glass factory in the United States. It was commenced only two years ago near New York, and we understand that it has met with encouraging success.

Soon after the introduction of the business into this country, a very great improvement in the mode of manufacture was introduced. Pallat, in his admirable work on glass, alludes to the American invention in only a few words, and passes it by as of but slight importance; but it has brought about a very great change, and is destined to exert a still greater; in fact, it has revolutionized the whole system of the flint-glass manufacture, simply by mould machines for the purpose of pressing glass into any form. It is well known that glass in its melted state is not in the least degree malleable, but its ductility is next to that of gold, and by steady pressure it can be forced into any shape. The writer has in his possession the first tumbler made by machinery in this or any other country. Great improvement has of course taken place in the machinery, insomuch that articles now turned out by this process so closely resemble cut-glass that the practised eye only can detect the difference. Still, the entire field of improvement is not occupied, and greater advances will yet be made. The tendency, in this particular, has been so to reduce the cost of glass that it has multiplied the consumption at least tenfold; and there can be no reasonable doubt but that, at this period, a much larger quantity of flint-glass is made in this country than in England. The materials composing glass are all of native production, and may be considered as from the earth. The pig lead used is all obtained from the mines in the Western States; ashes from various sources in other States; and silex is also indigenous. The materials consumed yearly, in the manufacture, are something near the following estimate:—

Coal, for fuel,48,000tons;
Silex,6,500"
Ash, Nitre, &c.2,500"
Lead,3,800"

for the flint manufacture. How much more is consumed by the window-glass manufacturers, the writer is without data to determine.

We have recorded the progress of improvement in the manufacture of glass, and now, relevant to the subject, we propose to examine the various improvements in working furnaces and glass-houses. To this end we present to our readers the drawing of a furnace for flint-glass,[1] with the interior of a glass-house as used by the Venetians, at the highest point of the art, in the sixteenth century.

[1] ] See drawing No. 1, at end of book.

The workmen in glass will see, that, as compared with the factories of the present day, the Venetians in their instrumentalities were subjected to many difficulties,—they were oppressed by the furnace smoke, and in no way protected from the heat of the furnace, or enabled to breathe fresh atmospheric air; in fact, the impression prevailed in those days that the external air, drawn into the glass-house, was detrimental to the business, and therefore it was most cautiously guarded against.

The drawing is taken from an ancient work on glass, and although limited in the view, shows the general plan. The factory wall was conical, and rose like a large chimney, with a few windows for the admission of light. Exposed to the heat of the summer sun of Venice, and of the furnace within, neither the comfort nor health of the workman was secured. The construction of the annealing department shows two tiers of pans, the use of which must have been attended with great loss of materials. Yet, with all the perceptible inconvenience, no material change in construction was made for centuries. The same plan was adopted in France and England, and it is only within the present century that any change has taken place in the latter country. In fact, in the year 1827 an Englishman erected a glass factory on the same plan in the vicinity of New York, which, from its defective construction for this climate, soon passed out of use.

The Germans, however, departed from the Venetian plan so far as to place the furnace in a large and well-ventilated building, but without a furnace-cone to carry off the heat and smoke; still a decided improvement was thus effected over the system in use in France and England.

The plan referred to shows to the practical workmen of the present day the excessive waste of fuel arising from the construction of the furnace; for the same expenditure of fuel in the American furnace would melt ten times the material produced from the Venetian.

It is admitted that the American glass-house is far in advance of the European ones at the present day, in the particulars of capacity, ventilation, comfort of the workmen, and economy in fuel. An impression is very prevalent that glass-making is an unhealthy occupation. It may have been thus in former times; but, as a matter of fact, no mechanical employment is more healthy. Dissipated as glass-makers have been in former days, and careless of their health as they are at present, no better evidence can be adduced to prove the generally healthy character of the employment than the fact that the Glass Manufacturing Company in Sandwich, averaging in their employment three hundred hands, had not a man sick through the influence of the employment, or one die in their connection, for the space of twenty years.

Drawing No. 2[2] represents the plan adopted in the French flint-glass furnaces. These at one period were worked by noblemen only,—the labor of the furnace-tender and taker-in being performed by servants, as before stated. The apparel and general style of dress, as indicated by the drawing, shows that more attention was paid to the fashion of the day than to comfort. The form of the furnace being similar to the Venetian shows it to have been subject to the same unnecessary waste of fuel; but it would appear that the French manufacturers had taken one step towards improvement, in using the waste fuel of the furnace to anneal their glass. The Venetians had a separate furnace to anneal their glass, supported by independent fires, as used at the present day.

[2] ] See drawing No. 2, at end of book.

The place marked D, over the crown of the furnace, is the door of the annealing oven; but the drawing is so imperfect that the artist does not show by what flues the smoke escapes, or in what way the glass was drawn from the annealing oven; for only the external view of the furnace is given. But it is fair to presume that the plan was the same as still exists in France, and as adopted by a French company now working a flint-glass factory in Williamsburg, near New York; viz.,—the taker-in, so called, mounts by steps to door D and places the articles in iron pans, which are slowly drawn over the furnace and through another door on the opposite side, to allow the glass vessels to cool gradually. The use of this plan is sustained by writers who describe the tools used to carry the glass articles into the upper oven to cool. In connection with the drawings of the ancient glass-furnaces, we deem it proper to give a drawing of glass-makers' tools[3] in use at that period, so that the glass-makers of the present day may observe with what instruments their noble predecessors in the art performed their labor.

[3] ] See drawing No. 3, at end of book.

In many of these tools we perceive the same general characters as mark those in use now. In some, improvements have been effected; while others are quite obsolete. It is quite curious to observe the etymology of many of the technical terms of the art in use at the present day. The name of the present polished iron table, i.e. the MARVER, is derived from the practice of the Italians and French in using slabs of polished marble. The iron now called the punty, from the Italian ponteglo. The tool now called percellas, from the word porcello. In fact, nearly all the technical terms in the glass manufacture, appertaining to the tool or furnace, are derived from the Italian. By referring to the drawing, we see that the tool marked A is the blow-iron, that marked B the punty-iron. Their character plainly indicates that the work made on them must have been confined to small or light articles. C, the scissors, D, the shears, correspond to those used at the present day. The tool marked E was used to finish part of their work. F and G were their large and small ladles,—the small used to take off the then called alkalic salt, showing that they were troubled with an excess of this in their time. The shovel, then called stockle, marked H, was used to carry glass articles to the annealing oven, forks not being then in use. The crooked iron I was used to stir up the metal in the pots. The tool L was used to form or hold large articles, their punty-iron not having sufficient strength. The tool M was used to carry flat articles to the annealing ovens. The tool N was used in refining their alkalic salts, and served to take off the salt as crystallized in course of its manufacture.

The workmen of the present day will see that, as before remarked, many tools are not altered in form, while in others there is a decided improvement,—in none more than in the tool E. Tool D is exactly like those now in use; but many new tools have been introduced since that period, rendering most of the old tools useless. Improvements in the form of glass-furnaces, construction of the glass-house, tools, &c., have been very gradual,—more so, in fact, than in almost any other art, when we consider that a period of about four hundred years has elapsed since the furnaces, tools, &c., herein referred to, were in use, and that they remained very much the same until the present century. It is indeed no undue arrogance of claim to say that the very many improvements in furnaces, working machinery, tools, &c. (such as enable the manufacturer here to melt with the same fuel double the quantity of glass that can at present be done in the European furnaces,) are entirely owing to the progress of the art in this country. By the perfection of our machines double the product can be obtained; and although the glass maker is paid at least three times the wages usually paid in Germany or France, we can, in all the articles where the value of the materials predominates, compete successfully with importers of foreign glass; but when the labor on glass constitutes its chief value, then glass can be imported cheaper than it can be manufactured in this country. Essentially, however, we may say, in the realm of art as in that of civilization and progress,—

"Westward the star of empire takes its way."