Engineering, Then and Now: Peter Schwamb and the Construction of the Mount Wilson Telescope

In December of this year, NASA will try to launch the James Webb Space Telescope (JWST). This project has suffered from delays, technical problems, and budget woes. In that respect, it is typical of Big Science endeavors. A century ago, the world’s largest telescope was under construction in greater Boston and going through the same pains. A Schwamb was right in the thick of it.

Mount Wilson 100 Inch Telescope, circa 1940 (Huntington Library, San Marino CA, #COPC 387)


Mount Wilson is located in Southern California, near Pasadena. Since 1905 the Mt. Wilson Observatory has operated research telescopes on the summit. In 1910 they began work on a one hundred inch diameter telescope, starting with the big mirror. While the glass was being “figured” into a precise shape to focus light, the observatory turned its attention to the mechanical system: a tube to hold the mirror, a mounting to aim the tube and track the sky, and a domed building to house it all.

The tube and mounting were a major project in metal fabrication, and in 1913 the observatory (hereafter “Mt. Wilson”) contracted with the Fore River Shipyard in Quincy, Massachusetts, to do the work. Mt. Wilson’s own staff, being on the other side of the continent, were in no position to supervise the project, so the observatory engaged Peter Schwamb to be their local engineering representative.

Professor Peter Schwamb (MIT Archives)

Peter Schwamb was the son of Peter Schwamb Sr., who was among the wave of brothers who emigrated from Germany to America. The father died before his son was born, and Peter was adopted by his uncle (and mill owner) Theodore Schwamb. Peter grew up in Arlington and studied mechanical engineering at MIT. He later joined the institute’s faculty and rose to a full professorship in the mechanical engineering department. He retired in 1911, and so was free for special projects when Mt. Wilson needed a machinery expert.

Peter’s official title was Consulting Engineer and Inspector, but his tasks included finding subcontractors, watching the budget, arranging logistics, and pressuring the often-uncooperative shipyard. In modern terms, he would be known as a program manager. The correspondence between Peter and Mt. Wilson is preserved in the observatory archives, and it is from those records that this story unfolds.

Schwamb As Engineer

When Peter joined the project, design of the telescope was far from complete. As plans for various components firmed up, Mt. Wilson would send preliminary blueprints to Schwamb. He would examine them for errors and suggest improvements, marking them up and sending them back. There was no Internet or fax, of course, but neither was there air mail. The drawings would travel in the mail cars of passenger trains, spending about five days in transit each way. Most communications between Peter and the observatory were by postal mail, but urgent messages would go by “night letter”: a discount telegram that was transmitted at night and delivered the next day. I could find no evidence that Schwamb and Mt. Wilson, building the biggest telescope in the world, ever discussed the project by telephone.

Peter would eventually redesign significant parts of the telescope, using the shipyard draftsmen to make the drawings. He also had to troubleshoot unexpected problems, and one of the worst was leaky tanks. The telescope mounting was to be equipped with two enclosed vessels that would “float” some of the weight and thereby lessen stress on the bearing mechanisms. Such floatation tanks had been successfully used in an earlier project and were not expected to cause problems. But when Schwamb pressure-tested them, they leaked. Water, in fact, came right through the metal walls.

The tanks were castings, made by pouring molten metal into a mold. As the metal cooled, little cracks and crevices opened up. Under high pressure, the water was able to find pathways from inside the tanks to outside. The situation was worse than it looked: in actual practice the tanks would be filled with mercury instead of water, and mercury is supremely good at finding its way through openings. Peter and Mt. Wilson fretted over how to plug the leaks, until Peter ran a second pressure test. He found that the leaks were less severe than before and guessed that rust was forming in the interior channels and partially blocking them. His proposed solution was to let even more rust form and thereby seal the metal. It worked.

Schwamb As Taskmaster

One of every program manager’s nightmares is an upheaval at the prime contractor, and this is what Peter faced. The telescope project suffered from unexpected competition from within the shipyard and a management change that oriented Fore River away from Mt. Wilson’s needs. As telescope work was starting, Fore River was building the first of two battleships for Argentina, the Rividavia. The Rividavia was plagued by cost overruns; Bethlehem Steel, which provided the raw material for the ship, became so worried that it bought the shipyard to assert control. The warship became Fore River’s priority project and the situation worsened when one of the ship’s engines was damaged during construction, necessitating rush work by some of the most skilled employees, men whom Peter needed for the exacting work on the telescope.

Mt. Wilson’s contract was what we would call “cost-plus.” The observatory would pay the shipyard for its actual costs plus a fixed profit of ten percent on those costs. Unfortunately, the contract did not specify a firm completion date. This left Peter with very little leverage over Fore River. For a year he cajoled management and bult working relationships with the employees to keep his project moving. But then the axe fell. Bethlehem sacked a number of managers, from the shop floor to the executive suite. Men with whom Schwamb had working relationships were gone, and the survivors would hardly be enthusiastic about a project that Bethlehem cared for not in the least.

Then in August, 1914, war came. Fore River received a contract to build twenty submarines for England. The work was to be rushed, of course, drawing men away from the telescope project and tying up shop machinery needed for telescope work. Progress on the mounting slowed to a crawl. All Schwamb could do was write angry letters to management, who regarded his project as an irritation of which they wanted to rid themselves. Well, said Peter, the way to get rid of it is to finish it. On this point, the shipyard agreed and promised to give the telescope priority. It was a promise upon which they would renege repeatedly.

Schwamb As Accountant

In the course of the project, Peter would track $100,000 of expenses, equivalent to roughly $2.5 million today. It was done with pencil, paper, and (probably) an adding machine. The money for his work came from the Carnegie Foundation, authorized in yearly installments. Schwamb had to be careful not to incur too many expenses at Fore River in any given calendar year. This would prove challenging, for unwelcome news in 1914 blew a hole in his budget.

The dome was the culprit. The round observatory building was to be capped with a rotating dome having an openable “shutter” through which the telescope could see the sky. The D. H. Burnham compamy of Chicago designed the dome, but it was so complex that Peter had trouble finding a fabricator to make the pieces to be assembled on the mountain. When the contract was finally let, the builder reported that Burnham had seriously underestimated the amount of steel required. This drove the dome’s cost much higher and the money had to be squeezed out of the work at Fore River.

Schwamb economized at every turn, but Mt. Wilson still had to ask for an emergency appropriation to keep the telescope going, a request that was fulfilled but brought severe criticism upon the observatory. As the project neared completion, Mt. Wilson made the drastic decision to perform some of the construction in its local shop so as not to spend too much money at Fore River. Peter was ordered to finish his own work as quickly as possible but not to go one dime over budget, a command that program managers have heard ever since.

Schwamb As Expediter

As 1915 was coming to a close, Mt. Wilson became frantic to get the telescope sent, in whatever state of completion, to California. The July date to which the shipyard had committed for finishing up had come and gone. The United States might be dragged into the European war at any moment, and who knew what obstacles the project might face if the instrument got stuck in Quincy. Another point of worry was the road up the mountain, which was unpaved. Late fall and early winter rains would make it impossible to truck the heaviest pieces up to the now-completed building, where they needed to be in place to start assembly promptly in the spring of 1916.

Today, if you have really big packages to ship, you can call a company like FedEx who will come pick it up and put it on trucks, trains, ships, and airplanes for delivery almost anywhere in the world. But in 1915, such “integrated” shippers did not exist. Peter would need to make all the transportation arrangements himself. There was no interstate highway system at the time; everything would go by freight train or cargo ship. Schwamb had to query different railroad lines to see which could provide the fastest coast-to-coast service. And he had to come up with the railcars himself–that was the responsibility of the customer, not the carrier.

At the time, rail freight was heavily regulated.  The Transcontinental Freght Bureau set rates for different types of cargo. Structural steel was tarrifed at low cost, while machinery was more expensive to ship. For a large piece of the mounting the classification was potentially ambiguous. It consisted of much ordinary iron and steel bolted and riveted together, but had some components that were more complicated and were, arguably, machinery. The first railroads with whom Peter inquired declined to take this cargo as structual steel, and when he found a carrier that would, he didn’t tell them that the other lines had refused. in fact, when this shipment got to California the Freight Bureau tried to assess the rate for machinery. But at that point it was a problem for Mt. Wilson, not Schwamb.

Meanwhile, the tube, though made in sections, was too big for rail transport–it had to go by sea. Peter was making arrangements with the Hawaiian-American line to take the tube from Boston to Los Angeles. But then a landslide closed the Panama canal. Hawaiian-American suspended all service from Boston and kept only limited sailings from New York. Schwamb was finally able to get the tube on a ship headed eastbound past the Cape of Good Hope and across the Indian and Pacific oceans, a long trip that consumed more precious time. But for once, luck was with the project. All the pieces got to California while the mountain road was still passable.


In the end, the hundred-inch telescope was a big success, coming online in 1917. It enabled major discoveries about the size and expansion of the universe and remained the world’s largest astronomical instrument until 1949. The complexities and hazards of its construction were a foretaste of what NASA program managers would experience with the Hubble and Webb projects. As JWST sits upon its Ariane rocket, awaiting the fateful countdown, Peter Schwamb could have sympathized with the tribulations that accompanied its development. He had seen them all.

Tom Calderwood, Schwamb Mill Preservation Trust, Inc.

Stories like this account of Peter Schwamb bring our industrial forebears to life! Researchers donate their time and effort because they value the Old Schwamb Mill and the history it represents. As the year ends, your contribution in support of the Mill’s Annual Appeal, however modest, is much appreciated! Visit the Mill’s Donation page to contribute securely online via PayPal or credit card.

2 thoughts on “Engineering, Then and Now: Peter Schwamb and the Construction of the Mount Wilson Telescope

  1. Peter J. Schwamb says:

    It is always an honor to read and hear more about my Great grandfather. Thank you Mr Calderwood for your interest and research.
    Petr J. Schwamb


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