Part 4

Having been rebuffed in Pittsburgh, he approached the Standard Plate Glass Company of Butler, Pennsylvania. Plate glass making, at least profitable plate glass making, was new in America and the Standard was one of the newer companies. Moreover, it was reputed one of the best plate glass makers in the country. Peate wrote to H. C. Tilton, general manager of the plant, asking him for a disc of glass without bubble or flaw 62 inches in diameter and 7 inches thick. He further advised him that he would see him in a few days. Tilton’s experience and that of his top supervisors was limited to the business of making ordinary plate glass. Therefore, he sought advice as to the feasibility of this fantastic project. He consulted George Howard, maintenance engineer of the plant, who had graduated from Cornell only a year before. George Howard, later to become noted as an inventor of glassmaking machinery, was at this time simply an optimistic young engineer.

“Howard, here’s a man at Greenville who wants us to cast him a disc 62 inches in diameter and 7 inches thick. Is that possible?”

Howard calculated the cubical contents of the proposed disc and replied that it was just barely possible. He didn’t see any particular difficulty in it. He thought the first few attempts might fail but felt that they could cast it successfully. Howard was later to ascribe his success more to his optimism and ignorance, rather than to any particular innovation he made. After being reassured by Howard, Tilton continued “Well, this Dr. Peate is coming down here tomorrow and he wants a quotation. How much do you think we ought to ask?”

“We’ll have some special apparatus to make and some experimenting to do. Then we’ll probably lose two or three pots of glass. I think you’d better ask him $800.” Howard thought that this was plenty. Tilton, however, was more cautious and doubled the price. Peate arrived in Butler on schedule. When Tilton named his price, Peate, of course, agreed instantly. Tilton was somewhat shocked and probably would have been more so had he known what St. Goubain had asked. At any rate the contract was placed with Standard, apparently in October 1894.

Having obtained a maker for his disc Peate immediately began making arrangements to prepare the disc. He contracted with the machine shop of a John Hodge for the tools with which the mirror would be worked. This small firm, The Hodge Manufacturing Co., employed only four men besides the owner. Among these was Frank A’Hearn, then just a boy, who became the prime source for details of the tools used by Peate in this work. Starting in November 1894 notes such as, “worked for Dr. Peate 3½ hours” begin to appear in his workbook.

The Hodge company made several (probably three) grinding tools for Peate. One was about 12 inches in diameter, and was to be used by hand. Two of the larger tools were provided with the male member of a ball and socket joint and were to be power driven. They were 30 and 48 inches in diameter, respectively. The largest was grooved to a waffle-like surface on its convex face. These grooves were about ½ inch wide and 3/16 inch deep. This pattern was ground by placing the tool face up on a wheeled buggy, which rode on cambered oak rails. As it was pushed along the length of the rail the grinding wheel on the radius arm cut one groove. When the groove had been cut, the radius arm was moved 2 inches along a line shaft and another groove cut. When all the grooves had been cut in one direction the tool was turned 90 degrees on the buggy and the other set of grooves was ground. The grinding of this tool took many weeks, and making the tools and apparatus for Peate may have kept Hodge busy for nearly six months.

The history of Peate’s 62-inch mirror probably would have remained as obscure as that of his others except for the furor which arose over casting the disc. The Erie Conference made no attempt to publicize this project, and both Hodge Manufacturing and Standard Plate Glass accepted Dr. Peate’s contracts as somewhat unusual but hardly newsworthy jobs. But when the glass trade became aware of Standard’s intention to cast this disc, a mighty outcry arose. Instead of encouraging Standard to complete this novel task the National Glass Budget, one of the leading trade journals, reviled them as “bumpkins” for attempting something that even the great glassmakers of Europe would not do.

It is hard to imagine why the trade journal so strenuously objected to Standard’s attempt. It has been suggested that it derived from the fact that Standard Plate Glass just previous to that time had refused to join in a combination of Pittsburgh companies which had set up a glass trust. Or it is possible that the young industry was afraid that an overly ambitious project doomed to failure might open American glassmaking to European ridicule and so harm the entire American industry. Whatever the reason, the Budget ridiculed Standard Plate Glass, and later Dr. Peate, for the attempt. They argued that it could not be done, but that if it were possible Pittsburgh would be the logical place to try it. Criticism and unfavorable comment came from other sources also, including “university professors from Meadville” (evidently Allegheny College). Nonetheless, Standard Plate Glass started the project.

George Howard was in charge of the casting operation. He planned to use the glass from a pot regularly used in the routine manufacture of plate glass. However, certain modifications were introduced in the procedure. The glass was to be poured on the traveling casting table, upon which was placed a circular mold made up of two semicircles of a special charcoal iron obtained from Philadelphia. This iron was not apt to generate bubbles of gas when in contact with the molten glass.

The iron mold was hinged at one joint of the semicircles, and the other joint was bolted. After the cast was poured it would be allowed to cool somewhat. When it was judged cool enough, it would be pushed into a kiln to be annealed. After it had remained in the kiln a certain length of time—again based simply on judgement—a quantity of pre-heated sand was to be poured over the mold as insulation. A further innovation was the use of a zinc sheet placed on the underside of the mold to avoid the possibility of trouble from grease on the casting table. This was the initial plan of operation.

Sometime early in 1895 the first attempt was made. It was an immediate failure. The zinc sheet, intended to protect the cast from grease, volatilized when the molten glass was poured on it, bubbled up through the glass, and, of course, ruined the cast.

The second attempt was evidently made sometime in March. The casting itself was successful. Sand had been substituted for the zinc sheet. The cast was placed in the kiln, and when it was thought to be set the insulating sand was poured over it. After a time variously estimated at from 4 to 11 days, the cast was considered sufficiently annealed, and was examined.

When the sand was removed, the disc was found in fragments. There was also a large concavity in what would have been the face of the disc. The sand had been poured over it before the glass was sufficiently set. However, the disc had been destroyed by its iron mold. The mold had contracted against the disc, bending the bolt and deforming the hinges, and this tremendous pressure had shattered the glass. The next issue of the trade paper jubilantly noted the failures. They also included Dr. Peate in their derision. They said in effect that at least this experience would save the old preacher the waste of many years of time and effort.

This slur on their most esteemed citizen brought the Greenville papers into the battle. The Budget had also made the mistake of implying that any number of Pittsburgh manufacturers were willing and able to make the disc. John Morrison, at that time editor of the Greenville Advance Argus, and source of much of our information regarding this controversy, immediately called the bluff of the trade paper, which was able to supply but one name, that of a George A. McBeth Company. This firm promptly declined without qualification. Later the name of the Phillips Semner Co. was given, and this firm guaranteed a perfect disc within 60 days for a “remunerative price,” but would not state what this price was. Therefore Dr. Peate could not deal with the firm.

Although the hue and cry continued for a few more weeks, the battle was really over, for Howard was soon to cast his disc. He had replaced the iron bolts in his mold with bolts of red oak dipped in nitric acid and then charred. The purpose of this was to relieve the strain on the glass by having the wooden pegs break as the mold contracted.

The third cast was in the kiln and in process of being annealed when Howard read in the Budget an article that set forth the difficulties of successfully casting optical glass. This article was anonymous and was obviously the work of an expert; it is thought to have been written by John Brashear. Although Howard was thoroughly discouraged by this article, the cast had already been made and no harm could be done now by allowing it to cool and be examined.

In May 1895 Howard, with the workmen, opened the kiln. The mold was loose, so the pegs had sheared as expected. When the sand was removed the disc was found to be whole. A close inspection revealed no obvious faults. The disc was gently carried to an inspection room and Dr. Peate was immediately sent for. He arrived, examined the disc for a moment, then said, “Give me a hammer.” Before anyone could move he seized a nearby hatchet and knocked off the sprue, or tail left as the pot was removed from the mold. The onlookers feared the lens would “explode,” as predicted by its detractors, but the only result was the removal of the tail, as Dr. Peate expected.

The Budget was still saying it couldn’t be done. Commenting on a May 1, 1895, announcement of the removal of the disc from the kiln, the paper seized on the fact that the disc was still warm to predict that it would be shattered before Peate could examine it, and reiterated its low opinion of Standard Plate. By the time this issue was in the hands of its readers however, the disc had been inspected and approved by Peate.

Newspapers in Pittsburgh and elsewhere carried the news of the great American disc. The embarrassed Budget replied that it was not talking about the mere casting of the disc but the completion of the mirror. It feigned surprise that this was all that was to be done in Butler. Even as late as May 24, 1895, the Butler Democratic Herald was still defending its town. It concluded an editorial on the issue thus:

… we have a feeling he [The Budget] has set his foot in it when he goes to poke fun at the Standard about casting the biggest mold on earth, and the end of it may be a repetition of the old saw “he who laughs last laughs best.”

A week before this, however, the success of this casting had been made more or less official by an announcement to that effect in the May 17, 1895, issue of Science, a publication of the American Association for the Advancement of Science and probably the most highly regarded scientific paper of the time.

On June 1, 1895, Standard Plate rendered Peate an invoice, not for $1600, but for $450. Evidently their work was done at cost. The disc was now removed to Greenville where Dr. Peate had erected a shop to grind, polish, and figure it. As the disc was slightly out of round the first operation was to make it perfectly circular. Peate did this roughly by spalling off pieces of the edge with his bricklayer’s hammer. The final rounding was done with the aid of the iron hoops that had made the mold. Dr. Peate fed steel shot between the edge of the disc and the iron semicircles. He rotated the disc on the turntable and thus rounded it off.

After this had been done he commenced the rough grinding. Using the large checkerboard tool, steel shot, and levigated emery Dr. Peate ground out a rough hollow. This took only a few days. George Howard stated that the depth of the concavity was about ⅝ inch and the shape correct to within about 1/10,000 inch. The calculated concavity of the mirror would be 6/10 inch. Peate evidently used the usual method in polishing the large mirror, that is, he covered the tool face with pitch and used rouge (iron oxide) as the abrasive. This method had been used for many years before this time and is still in use today.

The figuring, which consists of removing high spots to achieve a truly parabolic contour, probably took the longest time to complete. A mirror must be continually tested as this polishing is being done, and since the polishing warms the glass and distorts its shape, it is necessary to allow a long time for the glass to cool before it can be tested. Peate estimated that polishing and figuring the mirror took 750 hours.

We do not have a really accurate account of how he tested the mirror. Unfortunately none of the eyewitnesses to these tests had any knowledge of optics or of standard testing procedure. The information of those who had such knowledge is all at least secondhand and sometimes even more remote. J. W. Fecker, successor to Brashear, who was one of a group that examined the mirror in 1923, states that Peate did not use the knife edge test but that he did use a pin with a hole in its head in one of the tests used at that time.

A variety of different tests and diversions with the mirror have been reported. Dr. Peate would entertain visitors in various ways. One of these was to train the mirror on an apple orchard in a valley a few miles away. In another Peate would pull out one of his whiskers and hang it on a fence nearly a quarter of a mile away. Peate himself tells of the time spent in testing the mirror, but does not go into detail about the procedure. He does mention a testing table that stood about 75 feet away from the revolving table on which the mirror rested. He says further that the mirror was tested “in all ways known, in the shop and on a pin and a watch dial a thousand feet distant.” Of these only the pin test seems to have been a conventional one.

After the polishing, the mirror was silvered. Said Peate: “It was silvered and tried on the heavens in the starless region under Corvus, and under the very imperfect management of the mirror on telescopic stars, the report was as good as could be expected.” Dr. Peate must have spent some time testing it on the stars. The mirror was evidently completed sometime late in summer of 1897, and when Peate was satisfied that it was as perfect as possible, he made arrangements to send it to American University. He also designed the shipping case to protect it on the trip to Washington. It is described in the University paper as follows:

This consists of a box in which the glass is packed and a wheeled truck in which it is swung. It is swung on its edge by iron bands, which go around it over an iron belt which encircles it.