the history of itinerant glassworkers

Tag: 1670s

This Dutch glassworker used a Cartesian diver as a magic trick

As early as the 1670s, itinerant glassworkers were touring Europe demonstrating lampworking techniques to curious onlookers. A Dutch glassworker used this handbill to advertise his show in Wrocław, Poland, where he demonstrated at the Golden Sword (likely an inn or tavern). There, in the afternoons, the glassworker made glass eyes, weather-measuring devices, pots, bottles, and figurines.

handbill with text and two images of glassworkers blowing glass and using a cartesian diver

Dieser Hollaendische porcellain-glass-blaser, 1670? Collection of the Rakow Research Library, The Corning Museum of Glass, CMGL 112252.

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He also displayed a relatively new scientific experiment: a Cartesian diver. The diver, seen in full on the right above, was created to demonstrate the relationship between density and buoyancy. But the Dutch glassworker didn’t explain the science behind the Cartesian diver to his audience. Instead, he treated it as a magic trick, in which the demonstrator commanded the figures in the bottle to move up and down by calling out orders. In reality, he used his hand to add or remove pressure from the air-tight membrane at the top of the vessel.

Woodcut images of a man pressing down on the top of a Cartesian diver to create pressure

The glassworker presses down on the membrane covering the top of the Cartesian diver to create pressure and cause the figures in the bottle to move. Detail of Dieser Hollaendische porcellain-glass-blaser, 1670? Collection of the Rakow Research Library, The Corning Museum of Glass, CMGL 112252.

The glassworker included several figurines in his bottle: a toasting man, a queen, and what looks like perhaps a bear or a devil. (Cartesian divers were also know as Cartesian devils, water devils, and bottle imps.)

Tools of the trade

The handbill shows that this glassworker used a lamp similar to the one described by Johannes Kunckel in his 1679 translation of L’Arte vetraria (The Art of Glass). The flame was likely fueled by oil or tallow pulled through a cotton wick and the glassworker could shape and direct the flame using forced air (either supplied by the use of bellows hidden under the table or by blowing into a pipe directed at the flame). This glassworker also used a small blowpipe to make his products.

The glassworker offered to demonstrate at private residences upon request, and sold his products to interested observers. There is no price listed to see the show, which matches with other known advertisements from the period.

The case of the glass eye smuggler

And now for something completely different! Context posts are related to itinerant glassworkers in some – often tangential – way. Like a story about glass eye smuggling, a profile of a circus performer, or a post about the 19th-century roller rink craze.

In October 1911, United States customs agents arrested Bruno Schulze, a rather ordinary-looking business man, for smuggling 15,000 glass prosthetic eyes into the country. Over the next 12 months, the bizarre case of Schulze’s smuggling empire unfolded before a fascinated public.

Why would Schulze illegally import glass eyes? Lampworkers have been using glass to create prosthetic eyes since the 16th century. The material is durable, relatively comfortable, and, when shaped by an expert (called an ocularist), the resulting prosthetic is very realistic.1 German ocularists developed a special formula for glass that produced high-quality products, and their skills in making eyes were unmatched. So while ocularists created prosthetics in the United States, German-made eyes were more desirable. Schulze wanted to sell the best products, but wasn’t interested in paying the 60% duty charged by the U.S. government.2 So he hatched a plan to secretly bring the eyes into the country and spent more than a decade profiting from his scheme. Until customs agents caught on . . .

The “king” of glass eye smugglers

Black and white photo of Bruno “von Schoenewitz" and his signature

Bruno “von Schoenewitz,” 1909 and 1915 US passport applications. Source:

Name: Bruno C. L. Schulze
Alias: Baron von Schoenewitz (or the longer “Bruno Von Schoenowitz Freiherr Von Ungarswerth und Adlersloewen“)
Age: 43
Height: 5’7”
Eyes: Blue
Hair: Blond
Crime: Smuggling German-made glass eyes into the United States

Before the arrest

Customs officials had tracked Schulze for months, trying to pin him down. He’d been importing glass eyes for more than a decade, supplying ocularists around the United States. Some said he had a monopoly on the trade. Schulze was suspected of evading the 60% duty charged on foreign-made glass eyes. By doing so, he undersold other dealers and put many small firms out of business. Officials had finally gathered enough evidence to arrest him, thanks to a report from special Treasury agents who tailed Schulze in Europe while he bought 15,000 new glass eyes to sell on the American market. All that was left to do was find him . . .

Shallow box filled with glass prosthetic eyes

107 Glass Eyes with Box, Leopold Blaschka, possibly 1850-1887. Collection of The Corning Museum of Glass, 93.3.73.

October 30, 1911

Bruno Schulze was arrested as “Baron von Schoenewitz” upon his arrival in New York City on the steamship New Amsterdam of the Holland-American line. He was charged with smuggling 15,000 glass eyes into the United States.

November 3, 1911

newspaper clipping

The Brooklyn Daily Eagle, November 5, 1911.

Customs agents raided Schulze’s Hoboken, N.J., “factory” (a front for his smuggling business) and found 14,000 glass eyes, foreign bills of sale, and other paperwork they could use to prove his guilt.3 Philip Stroh, a local printer, was arrested on a charge of conspiracy. He was suspected of being Schulze’s fence (or middleman). Agents arrived at his office too late to seize the documents they were looking for, instead finding the “office stove burning brightly with papers.”

November 4, 1911

Schulze and Stroh were both released on $5,000 cash bails.4

newspaper clipping

The New York Sun, November 5, 1911.

November 5, 1911

New York and Washington, D.C., newspapers picked up the story, calling Schulze the “king” of glass eye smugglers. They described him as a “Handsome and Distinguished Looking” gentleman with a high forehead; blond, curly hair; mustache, and “superconfident eyes of blue.”5 He was not what came to mind when they thought of a smuggler. Customs agents had a different opinion. They told the New York Sun that Schulze had been in trouble with them before, and described him as having a “defiant air and bulldozing and unusually egotistical manner.”

November 18, 1911

The National Glass Budget wrote that Schulze was awaiting trial before United States Commissioner Edward Russ at Hoboken. Agents reported that Schulze used employees of German steamers to secretly transport the eyes on and off the ships.6

Detail of Preis-Liste über Emaille-Augen mit schwarzer Pupille, L. W. Schaufuss, 1866. Collection of the Rakow Research Library, The Corning Museum of Glass, CMGL 54006.

November 30, 1911

The story of Schulze’s arrest and the raid was reported around the nation. A reporter for the St. Paul Journal joked: “with all his eyes [Schulze] couldn’t elude the vigilance of the customs sleuths.”

December 3, 1911

newspaper clipping

Trenton (NJ) Evening Times, December 5, 1911.

Newspapers reported that customs special agent George P. Locke seized 600 glass eyes from the offices of St. Paul, M.N., optician W. H. Kindy.7 Kindy was not arrested, having purchased the eyes from Schulze without knowing of his criminal actions. Agents now estimated that Schulze smuggled 100,000 eyes into the country over the past 11 years, a $700,000 value. That meant Schulze owed the U.S. government about $420,000 in duties (roughly $10.5 million in today’s dollars).

January 5, 1912

newspaper clipping

The New York Sun, January 5, 1912.

Schulze’s problems were compounded when a customs inspector arrested him again, this time for importing glass animal eyes for less than half of their true value. Schulze’s bail was set at $10,000, which he was unable to pay. He was transported to the Tombs.8

February 17, 1912

Schulze was convicted on two counts for smuggling the shipment of 15,000 eyes into the United States. Prosecutor Mark P. Anderson believed Schulze would “get about all that the law allows.” The maximum sentence was four years with a fine of $10,000. Schulze’s associate, printer Philip Stroh, was reported to have supplied Schulze with “letterheads of a fictitious German manufacturer,” which he then used to get “false consular invoices” that undervalued the imported eyes.9

newspaper clipping

The New York Sun, February 19, 1912.

May 8, 1912

newspaper clipping

The New York Sun, May 9, 1912.

13,961 of the glass eyes seized in the raids were sold at a public auction in the Jersey City post office. According to the official announcement, only one eye in the lot was damaged. The Sun reported that the eyes “were packed in crates like strictly fresh eggs.”10 Two bidders split the lot, paying about 24 cents apiece. Buried at the end of the article was the news that Schulze was somehow able to escape and was at large.

June 4, 1912

The United States District Attorney’s office in Chicago filed United States vs. 2,659 glass eyes against the Geneva Optical Company for knowingly purchasing smuggled eyes from Schulze. The value of the glass eyes was set at $569. If the company could not successfully defend themselves, the eyes would be sold at public auction by the United States Marshal.

box with components showing how glass prosthetic eyes are made

Case of Glass Eyes, Tamworth Associates and F. and S. Danz, 1929-1940. Collection of The Corning Museum of Glass, 52.4.58.

October 4, 1912

newspaper clipping

The Montgomery (AL) Times, October 4, 1912.

Newspapers reported that the judge in the United States vs. 2,659 glass eyes case ordered the United States Marshals to auction off the eyes at a public sale.11

October 16, 1912

Bidder J. W. Sturtevant picked up all 2,659 glass eyes unopposed at the public auction. He paid the bargain price of $455. The Inter Ocean added some color, describing the eyes as “perfect blues, browns, grays, and blacks, and others with a blend of colors that never fail to attract.” From United States Marshal chief deputy John P. Wolf: “Are they not beautiful?”12

newspaper clipping

The Chicago Inter Ocean, October 17, 1912.

The end?

It is unclear what happened to Schulze, or whether he continued his criminal activities. In 1915, he used his alias to apply for a passport. His residence was listed as Philadelphia, P.A., and his occupation as merchant. After that, the trail dries up. Schulze/Schoenowitz fades from view.

glass prosthetic eye

Glass Eye, Leopold Blaschka, possibly 1850-1887. Collection of The Corning Museum of Glass, 93.3.73-24

So what do prosthetic eyes have to do with itinerant glassworkers? Several early glassworkers included glass eyes in their list of products. One such artisan not only made eyes of such quality “that they cannot be discerned from the Natural Eyes,” but also “he teacheth how [customers] may fix them in their Heads themselves, to the great Satisfaction of all persons that make use of them.”13 Spectacular!

How it works: Cartesian diver experiment

What is a Cartesian diver?

cartesian diver illustrated

Source: Elementary Treatise on Natural Philosophy Part I, A. Privat Deschanel, 1872, p. 108

A Cartesian diver is an experiment used to demonstrate the relationship between density and buoyancy.

Density describes how much matter is in a certain volume. Imagine filling two measuring cups, one with vegetable oil and the other with water. Now imagine placing those cups on a kitchen scale. You would find that one cup of vegetable oil has a mass of 223 grams and one cup of water has a mass of 240 grams. Vegetable oil has less matter in one cup than water, so vegetable oil is less dense than water.

Buoyancy is the ability of an object to float in water. If you poured the vegetable oil and water into the same container, the vegetable oil would be buoyant and float on the water.

You can change the density and buoyancy of a Cartesian diver at will, making it float or sink (hence Cartesian “diver”).

Cartesian divers are thought to be named for René Descartes. You may know them by another name, such as Cartesian devils, water devils, water dancers, or bottle imps. A Cartesian diver is made up of several parts: a bottle or vessel filled with water, a lid or an air-tight membrane, and a “diver” (often a piece of a straw or a flameworked glass object).

How does it work?

gif of glass cartesian diver in use

On the table in front of you sits a Cartesian diver. The diver is floating because it is less dense than the water. If you apply pressure to the vessel, the gas within the diver is compressed, and the diver’s density increases to the point that is no longer able to float in the water. Thus, the diver lives up to its name and sinks to the bottom. However, if you release the pressure, the gas expands to its original volume and the Cartesian diver becomes a Cartesian floater!

How did itinerant glassworkers use Cartesian divers?

Today, you might make a Cartesian diver in science class, but for hundreds of years they were made and used by itinerant glassworkers. These artisans made all sorts of models and contraptions to entertain their audiences, including Cartesian divers.

handbill with text and two images of glassworkers blowing glass and using a cartesian diver

Dieser Hollaendische porcellain-glass-blaser, 1670? Collection of the Rakow Research Library, The Corning Museum of Glass, CMGL 112252.

One of the earliest known records of these glassworkers is an advertisement for a demonstration in Poland circa 1670. On the right-hand side of the handbill, a Dutch glassworker is using a Cartesian diver with three figures, or “divers,” inside. Based on the description below the image, the glassworker promoted the experiment as a magic trick rather than a science experiment. He claimed he could command each figure to move up or down in four different languages and the figure would obey.

Cartesian divers remained a popular part of itinerant glassworkers’ shows, whether billed as magic or science. During the 1800s, many middle-class Americans wanted to be educated while they were entertained, and went to scientific demonstrations, lectures, and museum exhibitions in droves. Glassworkers accordingly included a growing number of experiments and lectures in their shows, and Cartesian divers were often shown alongside pulse glass circulators, philosopher’s hammers, cryophorus deception glasses, and hydro-pneumatic fountains.

a black and white photo with a man in a white coat and beret seated and flameworking at a table. on the table are a cartesian diver, a glass steam engine, and several other small models

John T. Backman Flameworking Glass Ship, McCroskey Studio, 1930s. Collection of the Rakow Research Library, The Corning Museum of Glass, CMGL 152150.

Itinerant glassworkers continued to perform into the 1900s, but the advent of mass entertainment drew audiences away from itinerant performers of all types. Glassworkers looked for alternative options, like starting their own stationary tourist attractions or joining a circus as a side show. Cartesian divers remained popular elements of their demonstrations.

How do you make a Cartesian diver?

gif demonstrating how a diy cartesian diver worksYou can make your own Cartesian diver with things you probably already have around the house and these step-by-step instructions.

This post was co-written by Kathryn Wieczorek; both Cartesian diver gifs are provided by her. A version of this post was originally published on the Corning Museum of Glass blog on April 4, 2017.

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