Glass does not exist in a natural form in many places. The sight of native crystal, probably, led men to think originally of producing a similar substance by art. The fabrication of glass is of high antiquity. The historians of China, Japan, and Tartary speak of glass manufactories existing there more than two thousand years ago. An Egyptian mummy two or three thousand years old, which was exhibited in London, was ornamented with little fragments of coloured glass. The writings of Seneca, a Roman author who lived about the time of our Saviour, and of St. Jerome, who lived five hundred years afterwards, speak of glass being used in windows. It is recorded that the Prior of the convent of Weymouth, in Dorsetshire, in the year 674, sent for French workmen to glaze the windows of his chapel. In the twelfth century the art of making glass was known in this country. Yet it is very doubtful whether glass was employed in windows, excepting those of churches and the houses of the very rich, for several centuries afterwards; and it is quite certain that the period is comparatively recent, as we have shown,[21] when glass windows were used for excluding cold and admitting light in the houses of the great body of the people, or that glass vessels were to be found amongst their ordinary conveniences. The manufacture of glass in England now employs twelve thousand people, because the article, being cheap, is of universal use. The government has wisely taken off the duty on glass; and as the article becomes still cheaper, so will the people employed in its manufacture become more numerous.
Machinery, as we commonly understand the term, is not much employed in the manufacture of glass; but chemistry, which saves as much labour as machinery, and performs work which no machinery could accomplish, is very largely employed. The materials of which glass is made are sand, or earth, and vegetable matter, such as kelp or burnt seaweed, which yield alkali. For the finest glass, sand is brought from great distances, even from Australia. These materials are put in a state of fusion by the heat of an immense furnace. It requires a red heat of sixty hours to prepare the material of a common bottle. Nearly all glass, except glass for mirrors, is what is called blown. The machinery is very simple, consisting only of an iron pipe and the lungs of the workman; and the process is perfected in all its stages by great subdivision of labour, producing extreme neatness and quickness in all persons employed in it. For instance, a wine-glass is made thus:--One man (the blower) takes up the proper quantity of glass on his pipe, and blows it to the size wanted for the bowl; then he whirls it round on a reel, and draws out the stalk. Another man (the footer) blows a smaller and thicker ball, sticks it to the end of the stalk of the blower's glass, and breaks his pipe from it. The blower opens that ball, and whirls the whole round till the foot is formed. Then a boy dips a small rod in the glass-pot, and sticks it to the very centre of the foot. The blower, still turning the glass round, takes a bit of iron, wets it in his mouth, and touches the ball at the place where he wishes the mouth of the glass to be. The glass separates, and the boy takes it to the finisher, who turns the mouth of it; and, by a peculiar swing that he gives it round his head, makes it perfectly circular, at the same time that it is so hardened as to be easily snapped from the rod. Lastly, the boy takes it on a forked iron to the annealing furnace, where it is cooled gradually.