The operations of the company, as it now exists, extend to six manufactories of mirrors, six manufactories of chemicals, a mine of iron pyrites, a salt mine, many thousand hectares of forests in this department of the Aisne and in the province of Lorraine, and to a local railway connecting St.-Gobain with Chauny, where the plate glass cast at St.-Gobain is polished and the mirrors are silvered. At St.-Gobain, besides the plate glass mirrors, glass is made for roofs, for floors, for pavements, for optical instruments, including the finest lenses used in the lighthouses of France. Here, as I have said, the lens was made now used at the top of the Eiffel Tower in Paris, from which, night after night, a gigantic auroral ray of electric light leaps into space and shoots for miles athwart the sky, to the inexpressible delight of the gaping crowds below, and I hope to the edification of the world of science.
Since 1870 the output of the company from its various manufactories has more than doubled. It now amounts, in round numbers, to 800,000 square mètres a year of polished plate glass; to 500,000 square mètres a year of rough glass; to a million kilogrammes a year of blocks and castings for floors and roofings, and to eighty thousand kilogrammes a year of optical glasses of all sorts.
In the time of Louis XIV. and before Lucas de Nehou had made his invention of plate glass, there was absolutely no public demand for what in those days were called 'large mirrors' made in the Venetian fashion, mirrors which to-day would not find a market in the most remote frontier towns of America or Australia. Colbert then wrote to the Comte d'Avaux apropos of the works of Lucas de Nehou in Normandy, that 'there was absolutely no market for large mirrors in the kingdom, the king being the only person who could possibly need them!'
This was in 1673.
In 1702, ten years after the invention of the process by which plate glass is made, a mirror with a surface area of one mètre cost 165 francs. In 1889 such a mirror costs 30 f. 25 c. A mirror with four mètres of surface area cost, in 1702, 2,750 francs. In 1889 it costs 136 francs.
When we come down to modern times and to the much larger mirrors produced of late years, the fall in prices is extraordinary. In 1873 a mirror with ten square mètres of surface cost 1,200 francs. To-day such a mirror can be bought at St.-Gobain for 467 francs, showing a fall of nearly two-thirds in price within sixteen years!
To-day the total production of polished plate glass in the world is estimated as follows:—
| square mètres | |
| England (4 companies) | 900,000 |
| Belgium (6 companies) | 600,000 |
| Germany (4 companies) | 150,000 |
| United States (7 companies) | 500,000 |
| France (not including St.-Gobain) | 130,000 |
| St.-Gobain | 800,000 |
| ———— | |
| Total | 3,080,000 |
From this it will be seen that nearly one quarter of the plate glass of a world in which plate glass, like champagne, is rapidly ceasing to be a luxury and becoming a necessity, is produced at this ancient establishment. With a keen perception of the tendencies of this age St.-Gobain, of late years, has been fitting its machinery to produce the very largest plates of glass possible to be made. Go where you like, from the Eden Theatre in Paris to the Casino of Monte Carlo, from the new monster hotel at the Gare St.-Lazare to the enormous edifice which an enterprising firm of tradesmen has planted in the centre of the Corso at Rome, and the vast glittering sheets of silvered glass turned out from the great forges everywhere confront you. At the French Exposition of 1878 St.-Gobain enabled the 'fly gobblers' of two hemispheres to admire themselves in the most gigantic mirror ever made down to that date. It measured six mètres and a half in height, by four mètres and eleven centimètres in width, which gave it a surface area of 26 mètres 12 centimètres. Naturally M. Henrivaux determined to surpass this prodigy in 1889, and to match the Eiffel Tower with a mirror. The Belgian rivals of St.-Gobain suspected this, it seems, and sent forth subtle persons to spy out the plans of the great French manufactory. These colossal plates of glass are cast upon immense 'tables' of metal, and by ascertaining the dimensions of the tables ordered for St.-Gobain the ingenious Belgians hoped to get the measure of the effort it would be necessary for them to outdo. In anticipation of this subtlety the director of St.-Gobain ordered two immense tables, and when these were sent to the manufactory, had them skilfully thrown into one. Upon the gigantic table thus prepared the grand mirror of the Exposition of 1889 was cast at the eleventh hour. This mirror was the special delight of the Shah of Persia during his visit of this year to Paris; and as I suppose the seven plate-glass manufactories which have grown up in my own beloved country under the benediction of the Protective Tariff, since a prohibitive duty was originally clapped on plate glass to encourage the one solitary establishment of the sort then existing in America, will give themselves up to producing something more stupendous still for the New York Exposition of 1892, I here set down its dimensions. It measures in height 7 mètres 63 centimètres, and in width 4 mètres 10 centimètres, giving it a superficial area of 34 mètres 24 centimètres. It is 12 millimètres thick, and weighs 940 kilogrammes. This enormous glass was cast from a single crucible, containing 1,600 kilogrammes of vitreous matter. To have seen this operation would have been worth a very much longer journey than that from New York to St.-Gobain, for the colour and glow of such a mass of vitreous matter in fusion can only be matched by the evanescent hues of a crimson aurora on a fine night in the North, or by the intense lights which play over the surface of a stream of molten lava.
At every stage in the operation the utmost skill and delicacy of handling are required to convert what might easily pass for a heap of rubbish swept together from a macadamised roadway into the smooth, glittering, lustrous plate which the French so picturesquely call a glace, and which indeed most nearly resembles the evenly frozen surface of a crystal lakelet. These sands, silicates, chalks, and carbonates—rough contributions from Oken's 'silent realm of the minerals'—are first crushed and mingled together by machines—one of the best of them, I was glad to hear, of American invention—then passed on into the great rectangular hall, in which they are shot into the crucibles of the melting furnaces and fused, mainly by gas, on a system invented and perfected by the late Dr. Siemens, I believe, who made such a stir a decade ago at Glasgow by his discourse on the storage of force before the British Association. The furnaces which, according to their varying capacity, now require from eight to ten tons of coal a day, consumed, before the development of the Siemens system, from sixteen to twenty tons. Twenty-four hours now suffice for the fusion and the casting of the glass, and if the casting were now to be conducted as ceremoniously as in the time of that fine old martinet M. Deslandes, M. Henrivaux would pass his life in a cocked hat, knee-breeches, peruke, embroidered coat, and sword, for the casting now takes place every day and at a fixed hour. None the less, rather the more, it is a work still of extreme nicety, one to be done by experts, who must be as cool as soldiers under fire. In a certain way and measure it is like ladling out the molten lava of Vesuvius and pressing it into slabs for a lady's toilette-table. The plates, once cast, must be smoothed and made even. This is a very pretty process, and used to be performed by machines which bore the very pretty names of valseuses. That paviour's rammers should be called demoiselles has always seemed to me an outrage and an impertinence, though I may suppose it finds its excuse in the short-waisted costumes of our grandmothers. But the movement of the glass-smoothing valseuses was really a sort of waltz movement. The plates of glass were fixed with plaster on a solid rectangular table. Granite-dust was scattered upon the plates, and then a wooden plateau, armed on the under side with bands of cast iron or steel, was set to waltzing over it backwards and forwards with a semi-rotatory motion, the granite-dust supplied becoming finer and finer as the waltzing went on.