Of the three main materials seen in modern offices, glass is the one with the most fascinating history and the most development to turn it from a useful but fragile material into one of the most vital components in construction.
Before glass was used in partitions, it needed to be made durable enough to withstand everyday use and strong enough to act as a structural component in an open-plan office.
The typical method of doing so with office glass is through a process known as tempering, where glass is heated or exposed to a particular chemical treatment that makes it both significantly stronger and much safer if it shatters.
Whilst the tempering process today is very complex, it was initially discovered by accident, and became the subject of one of history’s most notorious party pieces.
Is Prince Rupert’s Drop The First Toughened Glass?
The secret to the toughened glass seen today with balustrades, staircases and glass floors begins with a unique phenomenon known as Prince Rupert’s drops.
Contrary to the name, Prince Rupert of the Rhine did not invent them; they were initially forged in nature as Pele’s tears, and the secret to their creation was allegedly known to glassmakers as early as the Roman Empire.
Dripping molten glass quickly into cold water creates a rapidly-cooled tadpole-shaped droplet of glass that has phenomenally contradicting qualities.
On its bulbous side, it is amongst the strongest man-made materials on earth, capable of shattering bullets fired at it, being hit with hammers and experiencing enormous forces without breaking.
On its thin tail-end, however, the slightest disturbance to the tail can cause it to explode into a shower of tiny glass pieces, making it amongst the most fragile and delicate materials ever.
These contradictory actions are ironically caused by the same process used to make toughened glass.
What Was Toughened Glass First Used For?
Much like Pele’s tears, Prince Rupert’s drops were initially created by accident, often as the result of molten glass droplets falling during the blowing or shaping process.
Believed to have been known about since the Roman Empire, the earliest confirmed creation of the drops was in 1625, when they were known as Prussian tears (lacrymae Borussicae) or Dutch tears (lacrymae Batavicae).
Nobody was quite sure as to how they were so strong, despite the early efforts of great minds such as Margaret Cavendish, so there were two main initial uses of the drops, and toughened glass by extension.
Research Curiosity
The first was as a scientific curiosity; Prince Rupert of the Rhine, King Charles II’s cousin, was fascinated by the drops and gave them to the King of England, who then ensured their delivery to the Royal Society in 1661.
The Royal Society was fascinated by them, and managed to develop as comprehensive an account of their bizarre properties as was possible at the time.
The most authoritative of these up until 1920 was 1665’s Micrographia by Robert Hooke, which figured out everything about them other than the properties of elasticity and crack propagation, both of which would take centuries to fully discover.
Toys, Curiosities and Party Pieces
Given the unique properties of a Prince Rupert’s drop, it is perhaps unsurprising that they would quickly find a place in high society as a party piece, particularly amongst aristocrats who saw themselves amongst the intelligentsia of the time.
A common approach was to buy a drop or several, take it home and then attempt to break the bulbous end. After trying and indeed failing to break the glass despite using any heavy object or act of strength you can think of, you then snip the glass and see it explode into dust.
They became so common amongst high society that many works of literature of the era discussed them, usually as a metaphor for ostensibly strong people and parts of society which would shatter when exposed to a single weakness.
How Did Prince Rupert’s Drops Lead To Toughened Glass?
Before their properties were completely understood, the curiosity of Prince Rupert’s drops was applied to one of the most important construction materials in recent history, thanks in part to the pioneering work of Francois Bastie and Friedrich Siemens.
Both methods involved the same quenching process used to create Prince Rupert’s drops, but used a more controlled pressing method that ensured that the glass could be shaped into usable materials without the same obvious weakness that the teardrops had.
Around the same time as this, a similar method for laminating glass was created by accident, which led to the creation of two different methods for making glass stronger and more robust.
