The Story of Glass Part 17

For a long time the two children stood there fascinated by the skill of the blowers.

"Suppose we go on now and see the rest of the process," suggested Giusippe, a little unwillingly. "I could watch these men all day, but we have much to do, and if we do not hurry we shall not get through."

The next step in the work was opening out the cylinders, and this was done in two ways. The end of those made of thinner gla.s.s was put into the furnace while at the same time air was forced inside through the blow-pipe. As a result the air expanded by the heat of the fire, and burst open the cylinder at its hottest or weakest end. By placing this opening downward it was widened to the diameter necessary. The cylinders of thicker gla.s.s were opened by fastening to one end a lump of hot metal, thereby weakening them at this point. When the air was forced in by the blower it burst open the ma.s.s and the break thus made was enlarged by cutting it round with the scissors.

"Now come on, Jean, and see them flatten it out," said Giusippe.

Upon a wooden rest or chevalet the cylinder was now laid and detached from the pipe by placing a bit of cold steel against the part of the gla.s.s that still clung to the blow-pipe. At once the neck of the gla.s.s, which was hot, contracted at the touch of the cold metal and broke away from the pipe. The small end was then taken off by winding round it a thread of hot gla.s.s, and afterward applying cold iron or steel at any point the thread had covered.

"The cylinder is now finished at top and bottom and is ready to be split up the side," said Giusippe. "This they do with a rule and a diamond point mounted in a long handle. The diamond point is drawn along the inside of the cylinder and opens it out flat. If there are any imperfections in the gla.s.s the cutter plans to have them come as near the edge of this opening as possible so there will be little waste."

Jean nodded.

"Now, as you will see, the gla.s.s is ready for the flattener. First he warms it in the flue of his furnace and then, using his croppie or iron, he puts it on the flattening-stone; if you look carefully you will see that the top of this stone is covered with a large sheet of gla.s.s. In the heat of the furnace the cylinder with the split uppermost soon opens out and falls back in a wavy ma.s.s. See?"

Jean watched intently as the great roll of gla.s.s unfolded and spread into billows. The moment it was fairly open the flattener took his polissoir, a rod of iron with a block of wood at one end, and began smoothing out the uneven sheet of gla.s.s into a flat surface. At times he had to rub it with all his strength to straighten it. This done the flattening-stone was moved on wheels to a cooler part of the furnace and the sheet of gla.s.s upon it was transferred to a cooling-stone. When stiff enough it was taken off and placed either flat or on edge in a rack with other sheets.

So the process went on.

Cylinder after cylinder was blown, opened up, flattened, and annealed.

So quickly did the single sheets of gla.s.s cool that it was not much more than half an hour from the time they entered the flattening kiln before they came out thoroughly annealed. They were then carried to the warehouse for inspection and the especially fine ones were selected to be polished into patent gla.s.s. The sheets were rated as bests, seconds, thirds, and fourths, and their average size was 48 x 34 or 36 inches, although the foreman said that sometimes sheets as large as 82 x 42 or 75 x 50 had been made. These, however, were exceedingly difficult to handle, as they were in constant danger of being broken. The ma.s.s of gla.s.s was also very heavy for the blower to wield.

"The great advantage of sheet gla.s.s over crown gla.s.s is that it can be made in large pieces. Of course it is not as brilliant as crown, but it is much more useful," added the workman.

"What is crown gla.s.s?" whispered Jean to Giusippe.

"It is a variety of gla.s.s manufactured by another process," was the reply. "We do not make it here. Do you remember the bull's eye gla.s.s windows we saw in England? Well, each of those bull's eyes came from the center of a sheet of crown gla.s.s just where a lump of hot gla.s.s was attached so the blower could whirl or spin it from the middle and make it into a flat disc. But, as you can readily understand, a sheet of gla.s.s with this mark or defect right in the center will never cut to advantage, and therefore only comparatively small pieces can be got out of it; there is much waste. Yet, as the man says, it has a wonderfully brilliant surface. Now I am not going to let you stay here any longer or we shall not have time to see the part of the factory where I am working. I'm in the plate gla.s.s department, and I intend to drag you off to the casting hall this very moment."

Jean laughed.

"Before you go, though, you must understand that plate gla.s.s is quite a different thing from these others. It is not blown at all. Instead the melt is poured out on an iron table just as mola.s.ses candy is turned out of a pan to cool. You'll see how it is done."

They crossed the yard and entered another part of the works; Giusippe gave the foreman a word of greeting as they went in.

On each side of the great room were the annealing ovens, and down the center of the hall on a track moved a casting table which rolled along on wheels. The pots of molten gla.s.s or metal were first taken from the furnaces and carried on trucks to this casting table. Here they were lifted by a crane, suspended above the table, and then tilted over, and the gla.s.s poured out.

[Ill.u.s.tration: "THE MELT IS POURED OUT ON AN IRON TABLE"]

"For all the world like a pan of fudge!" declared Jean.

Giusippe laughed.

"I guess you would find it the stickiest, heaviest fudge you ever tried to manage," said he.

The instant the ma.s.s of soft metal was on the table a roller of cast-iron was pa.s.sed very swiftly back and forth over it, spreading it to uniform thickness, and at the same time flattening it.

"The thickness of the gla.s.s is gauged by the strips of iron on which the roller moves," explained Giusippe to Jean. "These can be adjusted to any thickness. Notice how rapidly the men have to work. The gla.s.s must be finished while it is hot, or there will be flaws in it. It is a rushing job, I can tell you."

"But--but you don't call this stuff plate gla.s.s, do you?" inquired the girl in dismay. "It does not look like it--at least not like any I ever saw used as shop windows or for mirrors."

"Oh, it is not done yet. But it is what we call rough plate. That's the kind that is used where light and not transparency is needed. You often see it in office doors or in skylights of buildings. To get the beautiful polished plate gla.s.s that you are talking about this rough plate must be polished over and over again. But before it can be polished it must first be annealed as rough plate. It goes into the annealing ovens right from this table and comes out all irregular--full of pits and imperfections. No matter how flat the casting table is, or how much care is taken, the surface of the gla.s.s after annealing is always bad. If it is to be made into polished plate it must be ground down first with sand and water; then ground smoother still with a coa.r.s.e kind of emery stone and water; next ground again with water and powdered emery stone. After that comes the smoothing process done with a finer sort of emery and water. Last of all the sheet is bedded, as we call it, and each side is polished with rouge, or red oxide, between moving pads of felt."

"Goodness!" e.j.a.c.u.l.a.t.ed Jean. "Do you mean to say they have to go through all that with every sheet of plate gla.s.s?"

"Every sheet of _polished_ plate," corrected Giusippe. "Rough plate does not need to be polished or ground down much. It is made merely for use and not for beauty. Sometimes to add strength, and help support the weight of large sheets, wire netting is embedded in them. Wired gla.s.s like this was the invention of an American named Schuman and it is used a great deal; the wire not only relieves the weight of the gla.s.s but serves the double purpose of holding the pieces should any break off and start to fall. Often, too, insurance companies specify that it shall be used as a matter of fire protection."

"But I should think if plate gla.s.s--I mean polished plate," Jean hurriedly corrected her error, "has to be ground down so much there wouldn't be anything left of it. It must come out dreadfully thin."

"The casters have to consider that and allow for it," answered the Italian. "They expect part of the gla.s.s will have to be ground away, so they cast it thicker in the first place. A large, perfect sheet of polished plate is quite an achievement. From beginning to end it requires the greatest care, and if spoiled it is a big loss not only in actual labor but because of the amount of material required to make it.

Even at the very last it may be injured in the warehouse either by scratching or breaking. It is there that it is cut in the size pieces desired."

"How?"

"With a rule and diamond point just such as is used for cutting sheet gla.s.s. The surface is scratched to give the line of fracture and then it is split evenly."

"I should hate to have the responsibility of cutting or handling it when it is all done," Jean observed with a little shiver.

"Well you might. Only men of the greatest skill and experience are allowed to touch the big, heavy sheets. The risk is too great. They turn only the best workmen into the plate gla.s.s department."

"But you work here, don't you, Giusippe?"

"I? Oh, I--I'm just learning," was the boy's modest reply.

"You seem to have learned pretty well," said a voice at his elbow.

Turning the lad was astonished to find Mr. Curtis standing just behind him.

"I must own up to being an eavesdropper," laughed the older man. "I couldn't resist knowing whether you were instructing Jean as she should be instructed, Giusippe. Don't worry. I have no fault to find. I couldn't have explained it better myself. You shall have your diploma on plate gla.s.s making any time you want it."

Then as the superintendent advanced to speak to him, Mr. Curtis added:

"You had given your pupil a good bringing up, Mr. Hines. He does you credit."

CHAPTER XI

JEAN'S TELEGRAM AND WHAT IT SAID

The winter in Pittsburgh pa.s.sed rapidly. For Jean it was a happy year despite much hard work at school, German lessons with Fraulein, and long hours of piano practising. It seemed as if the scales and finger exercises were endless and sometimes the girl wondered which had the more miserable fate--she who was forced to drum the same old things over and over, or poor Uncle Tom who had to listen when she was doing it. And yet as she looked back over her busy days she realized that she neither studied nor practised all the time. No, there was many a good time interspersed in her routine. For example, there was the Shakespeare play at the school, a performance of "As You Like It," in which Jean herself took the part of "Rosalind." This was an excitement indeed! Uncle Tom became so interested that he got out his book and spent several evenings coaching the leading lady, as he called the girl; one night he even went so far as to impersonate "Orlando," and he and Jean gave a dress rehearsal in the library, greatly to Giusippe's delight and amus.e.m.e.nt. This set them all to reading Shakespeare aloud, and going to a number of presentations of the dramas then being given in the city. To the young people all this was new and wonderful, for up to the present they had been little to the theater.

In the meantime Giusippe was also having his struggles. It was a rushing season at the factory, there being many large orders to fill; the mill hummed night and day and in consequence the scores of gla.s.s-makers looked happy and prosperous. No one was out of employment or on half pay, and none of the workmen dreaded Christmas because there was nothing to put in the kiddies' stockings.

With Christmas came Uncle Bob and oh, what a holiday there was then!

Was ever a Christmas tree so beautiful, or a Christmas dinner so delicious? Giusippe brought his aunt and uncle to the great house, and in the evening there was a dance for Jean and some of her school friends. Uncle Bob, who was in the gayest of spirits, danced with all the girls; introduced everybody to everybody; and brought heaping plates of salad to the dancers. There seemed to be nothing he could not do from putting up Christmas greens to playing the piano until the belated musicians arrived. The party could never had been given without him, that was certain. It was a Christmas long to be remembered!