THE INDUSTRY OF ALL NATIONS.

equal distribution of light over different ares of the horizon at equal dis-tances, is much less nearly approached in reflecting than in a catadiop-tric arrangement. Finally and conclusively: in an administrative point of view,the quantity of light obtainable in the combustion of equal quantities of oil inthe same time, is four times greater in the lenticular than in the reflector system.

And this verdict of experts is everjr year more and more being accepted andconformed to in the great National Light-House Establishments of the world.Since 1822, when the Cordouan Tower first received a Fresnel light, these lenses,of different sizes to suit circumstances, have become universal along the coast ofFrance. Holland was the next government to follow the example of France;and, after some efforts to manufacture the apparatus for its own national use,abandoned the attempt, and gladly reverted to the French workshops. The othermaritime nations also throng those shops; so that for some years it has been diffi-cult to have the various orders filled as promptly as they are wanted. Thus inthe five years, from 1846 to 1851, to go no lower than the 3d order lens, whichhas an inside diameter of nearly forty inches, there have been constructed ofthose great sea lights upwards of one hundred and twenty. In these every mari-time power has had a share. Russia only, at St. Petersburg, manufactures forherself under the guidance of the younger Soleil, by which the number may heincreased to about one hundred and forty, or more than one half, it is supposed,of all the stations where lights of the powers included would be considered ne-cessary. The whole number of lens lights in the world was estimated in 1851,apparently upon authentic statistics, at three hundred and sixty-eight; a numbertranscending all the lights, stationary and floating, existing upon the immense ex-tent of coast of the United States.

In this country, where the Light-House Establishment had been placed underan accounting instead of executive control, not much activity has been, until lately,displayed. The discussions in Europe since 1830, however, did not fail of attractingattention here; and at length, in 1838, an appropriation was made by Congressfor the purchase of two lenses from Paris. These, one of the first and the otherof the second order of Fresnel, were, after some time, placed at the Highlandsof Navesink, near the entrance of New-York Bay, where they are still, andmight seem to have been long enough, in spite of imperfections in their manage-ment, to have stimulated a more general acceptance of the system.

Some time after, in 1845, the then Secretary of the Treasury, Mr. Walker,took the subject up with his characteristic ability, and obtaining the detail of twoofficers of the Navy, Messrs. Jenkins and Bache, despatched them to Europe forthe purpose of examining and reporting on the Light-House systems there. Thisduty they performed to the entire satisfaction of the Department.

But at that period, several causes, and principally the absorption of the Go-vernment in the military operations that were then being carried on, preventedthe interest that was felt in the subject from being effectively exercised; and itwas only in 1851 that Congress authorized the creation of a provisional Board, toexamine into and report upon the condition of the Light-House Establishment ofthe United States, upon a plan somewhat in accordance with the recommenda-tions of the Hon. Secretary of the Treasury in 1846.

Early in the following year (1852), this Board presented a voluminous reportof inquiries, considerations, and recommendations. The plan of re-organizationsubmitted by it was approved by the then Secretary of the Treasury, Mr. Corwin,and, mainly by the lucid explanations of the Hon. Alexander Evans, of Maryland,whose name will always deserve to be mentioned in any notice of the Light-House system of the United States, was accepted and authorized by Congress.

By this authorization a permanent Board has been constituted with powerssufficient, it is believed, to carry out the aim and intention of Congress. It canhardly be amiss to add, that the character of the members composing it, offers asafe pledge of the judicious energy with which the necessary rectifications andimprovements will be carried out. To their courtesy is owing the opportunity ofshowing the present Lens which stands among the chiefest objects of enlightenedinterest in the Exhibition.

GLASS.

LTIIOUGH the display of glass in the present Exhibition is very far short ofwhat it ought to have been, to satisfy public expectation and the inherent in-terest of the subject itself; still there is enough in this class to convey muchinstruction, and to excite a praiseworthy curiosity to know, something more ofthe art of glass making than is commonly the share of intelligent people. We pro-pose in this article to present a concise and untechnical account of the art, drawnfrom the most reliable sources.*

* The article Glass in the Encyclopedia Metropolitana; that in Knapp’s Chemistry applied to Manufac-tures, Vol. III.; the Essay in the London Jury Reports, 1851, p. 521; and the chapters in Dumas’ Chem-istry on the same subject, form the most important and accessible papers upon glass.

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The origin of glass making is lost in the shades of an antiquity so remotethat it is not easy to distinguish fable from history. To the former mostcertainly belongs the absurd legend so often quoted from Pliny, that glass wasfirst formed accidentally by Phoenician dealers in native soda, who, haltingon the shores of the river Belus, and resting their kettles over the fire upon lumpsof soda, caused the sand of the shore to form glass with the alkali. A singlefact is worth all the speculation which ingenuity can invent, and such an one issupplied by the researches of Layard among the ruins of Nineveh, where hefound a perfect and beautifully formed vase of glass, now in the British Museum.It bears the marks of having been turned in a lathe, a process never attemptedin our times. The maker’s name is also engraved on its foot, and the circum-stances attending its discovery authorize the belief that it dates at least sevencenturies before the Christian era. The same indefatigable antiquarian has alsodiscovered in the ruins of the same city a convex lens of rock crystal, proving thatthe ancient Assyrians were, to some degree, familiar with the properties of light,as well as with chemistry. The inference seems well sustained also, that Archi-medes was acquainted with the scientific uses of glass, whether he used it or notfor the purpose of setting fire to the fleet of his enemies, as is usually related ofhim. Sir Gardiner Wilkinson (Yol. iii. p. 88), copies from a painting of BeniHossan the representation of two glass blowers inflating by hollow rods a massof molten glass. This Theban monarch reigned about 3500 years ago (1647 B. C.)and long before Moses became a pupil in the schools of Pharaoh. Wilkinson addsthat “ Glass vases, if we may trust to the representations in the Theban paintings,are frequently shown to have been used for holding wine as early as the Exodus,about 1490 years before the Christian Era.” We are led by numerous facts toentertain the conviction, that the Egyptians were well acquainted with manychemical processes, and that they attained considerable proficiency in the practiceof the chemical arts. This empirical knowledge was with superstitious care con-fined to the order of the priesthood, and was probably involved in the same mysterythat shrouded their religious rites with the design to magnify the holy office, andto inspire the people with a belief in the divine origin of the sacerdotal powers.Pliny in his chapter on this art (lib. 36, cap. 25), gives a curious and very interest-ing account of the. glass houses in Sidon and in Alexandria, which proves not onlythe early knowledge of the art of glass making, but also that the ancients prac-tised the modes now in use for cutting, grinding, gilding, and coloring.

However uncertain, therefore, may be the date of discovery of this most usefulart, it is certain, not only from what has been quoted, but also from all the otheraccounts from antiquity that have come down to us, from Herodotus, Strabo, Theo-phrastus and others, that the art was very early known, and carried to a high de-gree of perfection. It is, however, equally certain that its use in early times wasmuch restricted, and that even as late as the reign of Tiberius, after the know-ledge of Egypt had been transplanted to Rome, goblets and vases of glasswere regarded only as decorations for the tables of the Emperor and hiswealthy patricians. The Portland vase is the most beautiful specimenextant of these ancient goblets. It was found in the sarcophagus of Alex-ander Severus, who died A. D. 235, and is now in the British Museum.It is curious as showing the perfect state of the art at that time, beingformed of a deep cobalt blue body, covered by a white enamel, in imitation ob-viously of the onyx agate. The exquisite relievo figures upon it are the resultof cutting away this white surface, and exposing the dark ground, as was the cus-tom in the hard stone seal engraving of the ancients.

It has been doubted whether glass was ever fashioned by the ancients in sheetsfor admitting light in windows, but we remember to have seen in Pompeiia circular disc of glass 12 or 14 inches in diameter, filling its original placein a circular window in one of the recently excavated houses of that ancient Ro-man city. It should he borne in mind also, in forming an opinion on this subject,that the style of architecture in those days excluded windows, in accordance withthe climate and the habits of the people, which rendered them needless unless inrare cases. The antiquarians assert that the circular opening in the dome of thePantheon at Rome, was originally filled with one immense sheet of glass, but thismay well be doubted.

According to the local tradition of Yenice, the manufacture of glass is coevalwith the existence of the city itself; and a series of decrees of the Republic, com-mencing at the latter part of the 13th century, show that the art was carefully pro-moted until a change in the public taste deprived Yenice of her profitable mono-poly. In the 13th century, glass houses became so numerous as to expose thecity to dauger by fire, and in 1291, all the establishments were ordered to be re-moved to the separate island of Murano.

The skilled Greek workmen who escaped the taking of Constantinople in 1453,taught the Yenetians to enrich their productions by coloring, gilding, and enamel-ing. Early in the 16th century they invented a delicate and enduring mode ofenrichment—the introduction of threads of colored and opaque white glass intothe substance of the vessels. For tw® centuries the Venetians monopolised theglass trade of Europe; but at the commencement of the 16th century, heavycut glass became fashionable, and the trade being dispersed to Bohemia, France,and England, the manufacture of filagree glass lost its importance, though