This section is from the "The New Student's Reference Work Volume 5: How And Why Stories" by Elinor Atkinson.
Clean, white sand, soda and lime are put into enormous pots of fireclay in very hot furnaces. Some broken glass is added. For seed? Perhaps. It may be that the bits of glass, having been through the process before, are able to show the way to the raw materials. In making the big clay pots pieces of old pots are mixed with the raw clay. And scrap iron is added to pig iron. Dear, dear, who would think it. "Come on, all of you, I know the way," the broken bottles seem to say to the sand, lime and soda. So they all melt and run together. Whisk! A lot of matter out of place goes away into gas and leaves a thick, taffy-like, crystal paste in the pot, with some worthless skimmings on top brought up by the lime. You know how you have to skim the dirt and foam that boils up on taffy and jelly? So you do on glass and iron.
This is the first part of making all glass. Next comes the blower. He is a big, sweaty man with a pair of lungs like a blacksmith's bellows. His only tool is a six foot long, hollow iron pipe to blow bubbles with. It is just the stem of a pipe, really, for it has no bowl. He heats the end of the pipe in the furnace, then dips it into the hot glassy paste, and turns it around until he has gathered a lump as big as a goose egg. He swings this in the air to cool it a little, then dips it in to take up some more glass. A third time he does this. He now has a lump as big as a small melon, and that weighs eight or ten pounds. You know glass is very dense and heavy, like iron.
He cools the glass a little more in a water bath. Then he rolls it on a polished iron table to the shape of a little Hubbard squash or big pear. It is still very hot and soft when he begins to blow his big glass bubble. He stands on the edge of a pit to blow, for the weight drags the bubble out long, and his breath stretches it wide. As the bubble becomes thinner it cools more rapidly. So he takes it to the furnace to heat and soften it several times, until it is blown as thin as a pane of window glass.
At this stage he cuts off the neck of the bubble and the end, making a big cylinder, or open glass drum that he catches on his pipe and warms in an oven. The warm, soft glass cylinder is rested on a table, split from end to end with a diamond glass cutter and carried to another oven. Then, when soft, it is ironed out into a flat sheet. The sheet is tempered, or heated and cooled slowly, ironed and polished and cut into window glass for shipping.
Bottles are made by blowing small lumps of glass into iron or brass two-part moulds. Plate glass for show windows, and thick mirrors, is rolled. Liquid glass of fine quality, with no flaws or bubbles or color, is poured from the melting pots onto perfectly smooth steel tables and rolled with steel rollers into sheets, as your mother rolls pie-crust. It is so heavy that the pots are lifted and tipped by cranes, and the tables are carried on wheels to tempering ovens.
Two plates are rubbed together to polish them, and the polishing is finished by hand.
Flint glass, from which microscopes, spectacles and cut glass is made, is the finest of all. It must be as clear as water. This is moulded into "blanks," just the shape that is wanted. Then the patterns are cut on them with iron wheels, or "grindstones," on which water drips. A second and a third wheel are used to deepen the cuts and to polish them. The last wheel is of wood, covered with a soft powder, to give the cuttings a diamond brilliancy. It is all this work, and the danger of breaking in cutting and shipping, that makes our beautiful cut glass so costly.
The most costly of all is colored art glass for church windows, lamp shades and vases. The glass is first made clear white. Then it is painted with metal oxides (rust). The metals are reduced to powder with acids, as iron is rusted by the oxygen of the air. After painting, the glass is heated, melting the metal oxides all through it. So you see, when glass must be clear, as in spectacles and microscopes, cut glass and mirrors, no metals must be left in. Sands with metals can be used for cheap bottles, and these are often green or brown. In the fine stained, or art glass, the metals are broken up and painted on very carefully.
It is a curious thing that, although window glass is among the commonest and cheapest kinds made today, it is more difficult in some ways to make. Long after art glass was made, windows had still to be fitted with plates of mica, such as we use for the little windows in base burners. It was mica, no doubt, of which the apostle wrote: "We now see as through a glass, darkly." It was not until the thirteenth century that plate glass was made. But ancient glass-makers made bottles, cups, beads, dice, chessmen, hairpins, pillars for theaters and palaces with lamps inside of them, and even glass coffins.
The Egyptians seem to have made glass first. The Phoenicians learned the art of them and passed it on to the Greeks. The Romans learned it next, but the city of Venice raised glass making from a useful to a fine art. Venetian glass today is one of the art wonders of the world. Next a ruby glass was made in Bohemia.
Some of the great museums are proud of their historical collections of glass, with examples centuries and centuries old. They furnish chapters in the history of the world more important than jointed and chain armor, battle axes and swords. Over against the wars that destroyed lives and property were these conquests of peace. In the darkest, blood-stained ages, men were conquering the stubborn secrets of nature and building things of use and beauty. Did you know that we have added a chapter to the story of glass? We excel the world in glass cutting, and now we are making Tiffany art glass. It is quite unlike any art glass ever made before. It is used in church windows, lamp shades, and in many useful and ornamental forms. Some of it has all the colors and the airy, fragile grace of soap bubbles, as if deep sea shells and pearls were made transparent and luminous. To see it makes an American proud, for people who can make such a lovely thing have a place in the age-old procession of art, with Greek sculptures and Italian paintings. See Glass, page 772, Vol. II.