of cathedral, opalescent and art sheet glass, and all kinds of figured, ribbed and colored glass.

Machines for blowing bottles, at first adapted to wide-mouthed bottles only, were not commercially successful until about 1896. Such machines were operated at first by three skilled men, later by two and now by one. In 1908 there appeared a three-man machine for making narrow-necked bottles; in 1912, a oneman machine for wide-mouth bottles, and, in 1914, a one-man machine for narrow-neck bottles. The one-man machine automatically cuts off the quantity of molten glass sufficient for each mold. In establishments using machines bottles are blown by hand to fill small orders. From the earliest period of glass blowing until 1903 all glass that was blown was gathered on the end of a blow-pipe. In that year two revolutionary inventions were commercially introduced, the bottle-making machine by Michael J. Owens and the flowing device invented by Homer Brooke, both Americans. With only an attendant, who is not a skilled operator, the Owens machine gathers the glass and blows the bottle or jar. When a mechanical conveyor is used, the ware is both made and delivered to the lear without handling. More nearly automatic than any other glass-making machine, its output is much greater. The operating speed of the largest type of Owens machines is indicated by the fact that it produces more than 75,000 quart fruit jars in 24 hours. The machine and the revolving tank that supplies it are costly and are used only in factories which produce large quantities of bottles or jars of uniform shape and size. The machines were introduced in Europe and more recently in Japan. By the Brooke device the molten glass flows from the furnace to the mold, the quantity sufficient for each mold being automatically severed. The chief advantages of the Brooke device are that it dispenses with skilled labor; it can be operated during the hot months when hand gatherers are not readily obtainable, and by it the output is increased while the cost of production is decreased.

The making of coal-oil from coal led, about 1855, to a demand for lamps and lamp chimneys, the use of which greatly increased, about 1859, when refined petroleum was first marketed. One of the first plants to make a specialty of lighting goods was started in Brooklyn by Christopher Dorflinger, in 1852, but, in 1865, he moved the business to White Mills, Pa., where he established a large cutglass factory. Lamps and lamp chimneys are still manufactured in considerable quantities and exported to many countries. Chimneys were at first blown off-hand on blow-pipes. Chimneys, light tumblers and other seamless blown ware are now made in paste-mold machines, the seams being removed by turning the ware while hot in molds lined with carbon or similar material. The incandescent lamp was perfected by Edison in 1879 and its manufacture became an important branch of the industry. The bulbs are blown in paste-mold machines. All kinds of lighting goods are now extensively made in the United States.

The popularity of American made cut glass was established by a splendid display by the

Libby Company in a complete glass-melting and cutting establishment at the World's Fair, Chicago, in 1893. Both pressed ware and deepcut ware were exported to Europe before the war there began. Laboratory ware was little made in the United States before the war began in Europe, but since 1914 it has been produced here in quantities sufficient for domestic consumption and for export. Beakers and flasks equal to Jena ware have been made by one factory in New Jersey since 1900 and by plants in several States since 1914. Photographic glass was first made commercially in the United States in 1911 and the domestic production is now large. Optical glass was made experimentally in the United States in 1912. As a result of the war, the quantity manufactured here became large, the quality being equal to the best European product.

Even with the extensive use of machinery, labor constitutes the chief single item of expense in the manufacture of glass. Of 334 industries reported by the census of manufactures for 1914, glass ranked thirteenth in percentage of labor cost based on the value of the product. A government report, issued in 1917, shows that of the total sales value of the product, the cost of labor in the manufacture of various kinds of glass was 40.6 per cent. The same report shows that of employees in glass factories, 2.5 per cent were under 16 years of age and 8.2 per cent women, the latter being more numerous in tableware and lighting goods factories than in plants of other kinds. Hand window-glass blowers receive higher wages than skilled workers in other branches of the industry, and their working hours are relatively short, union hours being 44 a week. Unskilled workers average about 60 a week. Skilled labor is paid at piece rates, unskilled on a time-rate basis. In manufacturing window glass by hand and also blown and pressed ware, which includes tableware, bar goods, lighting goods and laboratory ware, the labor unions limit the output of workers, which restricts production and increases cost. Some branches of the industry operate only a part of the year, hand window glass only about seven months and machine window-glass plants about eight months, while other branches lose one or more months a year. The reasons are fear of overproduction, inability of men to work around furnaces during the hot months and necessity for repairs.

Accompanying tables show statistically the development of the industry in the United States from 1869 to 1914. While the estimated population increased 19.6 per cent from 1904 to 1914, the value of glass manufactures increased 54.6 per cent. Of the total value, $123,085,019 in 1914, window glass amounted to $17,495,956; polished plate glass, $4,554,326; pressed and blown ware, $30,279,290; bottles and jars, $51,958,728; other products, $4,022,932. In window glass, plate glass, pressed tableware, deep cut ware, lighting goods, laboratory ware and optical goods, the quality of the domestic product is equal or superior to the best that is imported.

The imports and exports of glass and glassware during the fiscal year 1879 were respectively $3,281,543 and $768,644; during the fiscal year 1914, respectively, $8,219,112 and $3,729,623.

greenish-gray or brownish; sides largely yellow, with narrow black streaks; but the coloration varies greatly, especially in western specimens. Several nearly related species inhabit Central America. These lizards are rapacious and devour great numbers of ground-keeping insects and crayfish. They breed by means of eggs hidden in loose soil or leaves; and are of slow growth. They are said to be easily tamed and to show intelligence.

GLASS-SPONGES,

certain silicious

sponges are so-called from the fact that the fibres or spicules composing their solid framework or skeleton is like finely spun glass. The glass-sponges, such as the Venus' flower-basket (Euplectella) and allied forms, live in fine sandy mud in deep water. The Euplectella inhabits the ocean around the Philippine Islands in from 10 to 20 fathoms. It forms a hollow cylinder or basket-work of spicules, enlarging at the top, which is broad and a little convex; it grows rooted in the sandy mud, anchored by its long glass spikes, which at the extremity end in anchor-like hooks. A number of similar but shorter, more dense sponges (Holtenia, etc.) live at great depths in the Atlantic, one kind occurring in shallower water (100 fathoms) in the Gulf of Maine. The glass-sponge of the Japanese seas is Hyalonema, in which the stem is twisted, composed of fibres, like spun glass, while the body of the sponge is long and slender; it grows nearly three feet in length. These glass-sponges, with the spicules having three crossed axes, or six threads radiating from a common point, are grouped in a family (Hexactinellida). The efferent canals are loosely meshed, while the digestive chambers (ampuliæ) are large and barrel-shaped.

GLASS STAINING AND GLASS PAINTING, the art of producing pictures on glass with vitrifiable colors; but a common extension of the meaning is to include all the make and design of ornamental glass windows. Originally there was but one method of making these, and that was to produce the pattern in outline with frames, into the grooves of which pieces of colored glass or of stained glass were fitted. In the Moslem East these frames were of plaster, or rarely of marble slabs pierced with openings. In Europe, since the 12th century, these frames have been of lead, rolled or drawn into what are called cames, that is, bars of an I section, the two grooves holding the glass firmly. Modern chemistry has so improved the art of glass staining that large pictures may now be produced on single sheets of glass, but nowhere have such pictures been successful in an artistic sense. In the original painted glass windows the pictures resembled tables of mosaic work, in which there was no attempt at shading or modification of the tone. What is perhaps the earliest known application of colored glass to window decoration, in Europe, is that in the monastery of Tegernsee, in Upper Bavaria, which was secularized in 1802, and is now a private residence. The windows of this structure, executed in the latter half of the 10th century, like all the first attempts, were only tasteful arrangements of colored glass in a translucent mosaic.

In the early part of the 13th century the mosaic patterns gave way to more elaborate designs, not only in beautiful arabesques, but

even in pictorial composition. In all these the figures were composed of pieces of colored glass combined with marvelous skill and taste. The work of shading and making so-called half-tints was not attempted; but an effect not dissimilar was got by painting in opaque pigment upon the glass and breaking up this painted surface into patchings and spots as when an artist draws in crayon or charcoal. The finest English examples of this early mosaic work are to be found in the cathedrals of Canterbury, Salisbury and Lincoln. In the 14th century the art of shading was advanced by removing certain portions of the colored surface.. The first period of the art reached the culminating point in the 15th century, but with the passing of Gothic architecture, glass painting lost its artistic spirit. Subjects in which were arranged a multitude of personages with all the elaborate artifices of pictorial composition; buildings showing complex linear perspective; foreshortened figures; the play of light and shade-all this was attempted to be exhibited in painted windows. It soon became apparent that the true art was lost, and though windows continued to be painted, only a few artists acquired celebrity. Perhaps the best examples of the 15th century period are the windows of the Cologne Cathedral.

About 1600, Bernhard von Linge, an artist from the Netherlands, residing in England, and who may be considered the father of the modern art of glass staining, established a school in London, whose influence is evident in the work of the present day. Francis Eginton (1737-1805), a native of England, accomplished much to restore the art during the 18th century. Among his numerous works, all of which are remarkable for brilliancy of coloring and delicacy of execution, are 'The Banquet of the Queen of Sheba (a copy from Hamilton); two Resurrections (from Sir Joshua Reynolds); Christ Bearing the Cross' (from Morales); and 'The Soul of a Child' (from Peters). Other famous artists of this period were Jouffrey and Baumgartner. The Renaissance in glass painting was contemporaneous with the revival of Gothic architecture in the beginning of the 19th century. Four German artists, Mohn, Scheinert, Ligm and Frank, were prominent as glass stainers during the century. In 1850, through the generous assistance of King Louis of Bavaria, a school was founded at Munich under the direction of Gärtner and Hess, the latter a well-known historical painter, which obtained a world-wide celebrity. Still, however, the purists in Gothic art, and those who were most concerned in the Gothic revival would have none of this glass of the early 19th century. It was seen that the smooth and clear modern glass would never do; and rough, partly opaque, flawed and bubbled glass was prepared on purpose. This material, known as "antique" and as "cathedral" glass, and by other names, allowed of a far more decorative effect.

The chief centres of the art in Europe are at Birmingham, England; Edinburgh, Scotland; Paris and Sèvres, France, and Munich, Metz and Nuremberg in Germany.

Not until comparatively late in the 19th century did the art of glass staining obtain a place in the United States. Only a few years ago Americans were seemingly content with imported windows, or with poor imitations made