HISTORY77 - Fifteen Accidental Inventions that Changed the World

Introduction

I’ve been blogging lately about inventions - some on purpose inventions, some accidental.  This blog concludes the series of four article with:  Fifteen Accidental Inventions that Changed the World.  These include:  penicillin, X-rays, the blood thinner warfarin, implantable cardiac pace makers, pap smear, quinine, anesthesia, Viagra, Botox, smoke detectors, laminated safety glass, dynamite, vulcanized rubber, stainless steel cutlery, and dry cleaning.

 

For each of these 15 inventions, I will summarize the invention’s history and relate my (and/or Pat’s) personal experiences with the invention.

My principal sources include “30 Life-Changing Inventions That Were Totally Accidental,” bestlifeonline.com; “7 Momentous Inventions Discovered by Accident,” history.com; “The Best Accidental Inventions,” inventionland.com; “9 Successful Inventions Made by Accident,” concordia.edu/blog; “15 Of the Coolest Accidental Inventions,” science.howstuffworks.com; “10 Accidental Discoveries That Changed the World,” rd.com; plus, numerous other online sources.

So here are my fifteen accidental inventions that changed the world, in no particular order.

Penicillin

Penicillin was the first antibiotic developed to treat bacterial infections.  Before penicillin was discovered and made into an antibiotic, having a simple scratch could lead to an infection that could kill.  Using penicillin and other antibiotics has saved many thousands of lives.

Note:  Antibiotics are not effective against viruses such as the common cold or influenza.  They are also not effective against fungi.

Bacterial infections can occur throughout the body, including skin, teeth, ear, nose, throat, and lungs.

Common infectious diseases caused by bacteria include strep throat; salmonella (in intestinal tract); tuberculosis; whooping cough; syphilis, chlamydia, gonorrhea and other sexually transmitted infections; urinary tract infections; E. coli (in intestines, can cause severe stomach cramps, bloody diarrhea and vomiting); and clostridioides difficile (in large intestine, causes diarrhea and colitis, and inflammation of the colon).

There is good historical evidence that ancient civilizations used a variety of naturally available treatments for infection, for example herbs, honey and even animal feces.  One of the more successful treatments was the topical application of moldy bread, with many references to its beneficial effects from ancient Egypt, China, Serbia, Greece and Rome.  This theme of the benefit of molds continued over the years, with references by English botanist John Parkinson in his book Theatrum Botanicum, published in 1640.

In 1928, Dr. Alexander Fleming, a Scottish physician and bacteriologist, discovered penicillin and opened the world to antibiotics.  Returning to St. Mary’s College in London from a two-week vacation, in 1928, Fleming realized that he had left cultures of Staphylococcus aureus in a petri dish in his lab, which he meant to throw away before he left.  To his surprise, some of the cultures had died.  Further investigation led Fleming to discover that a fungus, which had grown in the culture, had destroyed the bacteria.  The type of fungus he found was a mold called Penicillium notatum, a type of fungus that is similar to the mold that grows on bread. 

Fleming published his findings in the British Journal of Experimental Pathology in 1929, but the report didn’t garner much interest.

Then in 1938, Ernst Chain, a biochemist working with pathologist Howard Florey at Oxford University, came across Fleming’s paper while he was researching antibacterial compounds.  Scientists in Florey’s lab started working with penicillin, which they eventually injected into mice to test if it could treat bacterial infections.  Their experiments were successful and they went on to test it in humans, where they also saw positive results.

Penicillin was discovered as mold on a laboratory petri dish.

 

By 1941, there was an injectable form of penicillin that could be used to treat patients.  But there were difficulties in growing large quantities of the mold in England during World War II, so Florey turned to the United States; mass cultures of the mold were produced quickly.  In July 1943, the U.S. War Production Board drew up a plan for the mass distribution of penicillin to fight bacterial infections of Allied troops fighting in Europe.  The U.S. was able to produce 2.3 million doses in time for the invasion of Normandy in the spring of 1944.   

Penicillin and its variants are still widely used today for different bacterial infections, though many types of bacteria have developed resistance following extensive use.

I was born (1940) just as penicillin became available as a medication.  Ironically, this wonderful drug is the only medication that I am allergic to (hives).  Pat had penicillin a few times in her younger years.

X-rays

In 1895, German physicist Wilhelm Conrad Rontgen, was investigating electrical discharges from a vacuum tube in his laboratory in Wurzburg, Germany.  He had wrapped the vacuum tube in black cardboard so that the visible light from the tube would not interfere.  He noticed a mysterious faint green glow from a chemically-treated fluorescent screen about three feet away.  Rontgen realized that some invisible rays coming from the tube were passing through the cardboard to make the screen glow.  He found they could also pass through books and papers on his desk.  Confused and intrigued, he named the new rays causing this glow X-rays, due to their unknown origin.

Rontgen threw himself into investigating these unknown rays systematically.  He discovered their medical use when he made a picture of his wife's hand on a photographic plate formed due to X-rays. This was the first photograph of a human body part using X-rays. Two months after his initial discovery, he published his first paper.

The first “medical” X-ray, taken of the hand of Wilhelm Rontgen’s wife, on 22 December 1895.

 

The discovery of X-rays generated significant interest.  Rontgen’s biographer Otto Glasser estimated that, in 1896 alone, as many as 49 essays and 1044 articles about the new rays were published. This was probably a conservative estimate, if one considers that nearly every newspaper around the world extensively reported about the new discovery, with a magazine such as Science dedicating as many as 23 articles to it in that year alone.

The first use of X-rays under clinical conditions was by John Hall-Edwards in Birmingham, England on January 11, 1896, when he radiographed a needle stuck in the hand of an associate.  On February 14, 1896, Hall-Edwards was also the first to use X-rays in a surgical operation.

Technology improvements in X-ray generation and assessments for medical imaging have led to improvements in the diagnosis and treatment of numerous medical conditions in children and adults.

Today, there are three main types of medical imaging X-ray applications.

Radiography - a single image is recorded for later evaluation.  Mammography is a special type of radiography to image the internal structures of breasts.

Fluoroscopy - a continuous X-ray image is displayed on a monitor, allowing for real-time monitoring of a procedure or passage of a contrast agent ("dye") through the body. 

Computed tomography (CT) aka computed axial tomography (CAT) - many X-ray images are recorded as the detector moves around the patient's body.  A computer reconstructs all the individual images into cross-sectional images or "slices" of internal organs and tissues. 

As many of us have, over my lifetime, I have had several dental X-rays, diagnostic chest X-rays, and X-rays to set and monitor broken bones.  Pat also has had dental and chest X-rays, as well as numerous mammograms, bone-density scans, and lately diagnostic CT scans.  All in all, X-rays have been vital to our prolonged active lives.

Blood Thinner Warfarin

Warfarin, a common blood thinner, was discovered not in a lab but in a field, where livestock were dying from a mysterious disease.

In the 1920s, cattle and sheep that grazed on moldy sweet clover hay began to suffer from internal bleeding.  Many previously healthy animals also bled to death after simple veterinary procedures.  A Canadian veterinarian, Frank Schofield, determined that the moldy hay contained an anticoagulant that was preventing their blood from clotting.  In 1940, scientists at the University of Wisconsin, led by biochemist Karl Link, isolated the anticoagulant compound in the moldy hay.  A particularly powerful derivative of the compound was patented as warfarin, named after the Wisconsin Alumni Research Foundation that funded its development.

But before it was used medicinally in humans, warfarin was used as rat poison.  In 1948, it was approved for use as a rodenticide.  It wasn’t until the mid-1950s that warfarin entered clinical use.  It was formally approved as a medication to treat blood clots in humans by the U.S. Food and Drug Administration in 1954.  Among its early patients was President Dwight D. Eisenhower, whose 1955 heart attack was treated with warfarin.

Warfarin is usually taken by mouth.

 

While the drug is described as a "blood thinner,” it does not reduce viscosity but inhibits coagulation, and is commonly used to prevent blood clots in the circulatory system such as deep vein thrombosis and pulmonary embolism, and to protect against stroke in people who have atrial fibrillation, valvular heart disease, or artificial heart valves. 

It is usually taken by mouth, but may also be administered intravenously.

Excessive bleeding is the most common side effect of warfarin.

Today, about 2 million people in the United States take warfarin, available as Coumadin® or Jantoven®.

Neither Pat nor I have ever had warfarin.  We both take other anticoagulants today, so we probably owe a debt to the discovery and success of warfarin.

Implantable Cardiac Pace Maker

An implantable cardiac pacemaker is a battery-powered device that is placed under a person's skin that helps the heart perform normally.  The device sends electrical pulses to keep the heart beating at a regular rhythm, preventing potentially life-threatening complications for irregular heartbeats in many patients.

In 1956, adjunct professor of engineering at the University of Buffalo, Wilson Greatbatch, was working on a device to record the rhythm of a human heartbeat, but he used the wrong-sized resistor in the circuit.  The device created intermittent electrical impulses that closely mimicked the sound of a human heartbeat.  Greatbatch discovered that from his invention he could run electrodes directly to the muscle tissue of the heart, keeping a patient's heart on track. 

While hospitals already had pacemaker machines, they were large, painful, and immobile.  Greatbatch realized that a pacemaker implanted in the human body would allow patients who needed pacemakers not have to remain at the hospital, and they wouldn't have to use the painful machines. 

In 1958, Greatbatch collaborated with Dr. William Chardack of the Buffalo Veterans Administration Medical Center and Dr. Ander Gage to implant an electrode in a dog attached to a pulse generator. They worked for the next two years to refine their design of a unit that could be implanted in the human body and would maintain the same pulse rhythm for long periods of time.

In 1960, they implanted a pacemaker into a 77-year-old man, who lived for 10 months after the surgery. In that same year, they implanted pacemakers into nine other patients, several of whom lived for more than 20 years after the implant.  

Greatbatch and Chardack’s design was the first implanted pacemaker to be commercially produced.

Modern pacemakers are externally programmable and allow a cardiologist to select the optimal pacing modes for individual patients.  Most pacemakers are “on demand,” in which the stimulation of the heart is based on the dynamic demand of the circulatory system.  Others send out a fixed rate of impulses.

Today, more than 3 million people worldwide have implanted cardiac pacemakers.

Wilson Greatbatch holding the first implantable pacemaker.

 

Thankfully, neither Pat or I have needed a cardiac pacemaker.  However, my brother had one “installed” last year, and is doing fine.

Pap Smear

The American Cancer Society's estimates for cervical cancer in the United States for 2023 are:

a.       About 13,960 new cases of invasive cervical cancer will be diagnosed.

b.       About 4,310 women will die from cervical cancer.

The Pap smear is a medical screening test designed to identify abnormal, potentially precancerous cells within the cervix (opening of the uterus or womb) as well as cells that have progressed to early stages of cervical cancer.  In the test procedure, a small brush is used to gently remove cells from the surface of the cervix and the area around it so they can be checked under a microscope for cervical cancer or cell changes that may lead to cervical cancer.  A Pap smear may also help find other conditions, such as infections or inflammation.

The test was invented by and named after the Greek doctor Georgios Papanikolaou.  In 1923, while observing a slide of cells taken from a woman's uterus, Papanicolaou came up with the idea for the Pap smear to test for cancer.  Originally, Papaniculaou's intention was simply to observe cellular changes during a woman's menstrual cycle, but during his study, he discovered that one of his patients had uterine cancer - and that her cancer cells could easily be viewed under a microscope.

The Pap test was finally recognized only after an article in the American Journal of Obstetrics and Gynecology in 1941 by Papanikolaou and Herbert F. Traut, an American gynecologist.  A monograph entitled Diagnosis of Uterine Cancer by the Vaginal Smear that they published contained drawings of the various cells seen in patients with no disease, inflammatory conditions, and preclinical and clinical carcinoma.  Both Papanikolaou and his wife, Andromachi Papanikolaou, dedicated the rest of their lives to teaching the technique to other physicians and laboratory personnel. 

Pap smear showing abnormal squamous cells.

 

Over the years, the Pap smear has saved many lives.  Medical guidance today is that women aged 21 to 29 should have a Pap test about every three years.  Those aged 30 to 65 should have a Pap test every three to five years.

Pat has had regular pap smears over her lifetime, thankfully all negative.

Quinine

Malaria is a mosquito-borne infectious disease that affects humans and other animals.  Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches.  In severe cases, it can cause jaundice, seizures, coma, or death.   Over millennia, its victims have included Neolithic dwellers, early Chinese and Greeks, and princes and paupers.  In the 20^th century alone, malaria claimed between 150 million and 300 million lives, accounting for 2 - 5% of all deaths.

The discovery of quinine is considered the most serendipitous medical discovery of the 17^th century and malaria treatment with quinine marked the first successful use of a chemical compound to treat an infectious disease.

Quinine, as a component of the bark of the cinchona tree, was used to treat malaria from as early as the 1600s, when it was referred to as the "Jesuits' bark," "cardinal's bark," or "sacred bark."  These names stem from its use in 1630 by Jesuit missionaries in South America, though a legend suggests earlier use by the native population.  According to this legend, an Indian with a high fever was lost in an Andean jungle.  Thirsty, he drank from a pool of stagnant water and found that it tasted bitter.  Realizing that the water had been contaminated by the surrounding cinchona trees, he thought he was poisoned.  Surprisingly, his fever soon abated, and he shared this accidental discovery with fellow villagers, who thereafter used extracts from the cinchona bark to treat fever.

Before 1820, the bark of the cinchona tree was first dried, ground to a fine powder, and then mixed into a liquid (commonly wine) before being ingested.  In 1820, quinine was extracted from the bark, isolated and named by Frenchmen pharmacists Pierre Joseph Pelletier and Joseph Caventou. Purified quinine then replaced the bark as the standard treatment for malaria.

 

Drawing showing the source of the anti-malaria drug quinine.

Quinine remained the mainstay of malaria treatment until the 1920s, when more effective synthetic anti-malaria drugs became available.

As of 2006, quinine is no longer recommended by the World Health Organization as a first-line treatment for malaria, because there are other substances that are equally effective with fewer side effects.  Quinine is still used to treat lupus.  While quinine is not approved by the FDA for the treatment of arthritis, some people use it as a natural remedy for pain relief.  Quinine is thought to have anti-inflammatory properties, which may help reduce swelling and pain in the joints.

Thankfully, neither Pat nor I have contracted malaria and therefore never required quinine.  Similarly, we have not needed to take antimalarial drugs on our travels.

Anesthesia

Early anesthesia (probably herbal remedies) can be traced back to ancient times (Babylonians, Greeks, Chinese, and Incas), but one of the first European accounts occurred in the 1200s when Theodoric of Lucca, an Italian physician and bishop, used sponges soaked with opium and mandragora (from the mandrake plant) for surgical pain relief.  Hashish and Indian hemp were also commonly used as painkillers.

Up until the mid-1800s, however, surgeons could not offer patients much more than opium, alcohol, or a bullet to bite on to deal with the agonizing pain of surgery. 

The most famous anesthetic, ether, may have been synthesized as early as the 8^th century, but it took many centuries for its anesthetic importance to be appreciated, even though the 16^th century physician and polymath Paracelsus noted that chickens made to breathe it not only fell asleep but also felt no pain.  By the early 19^th century, ether was being used by humans, but only as a recreational drug.

Meanwhile, in 1772, English scientist Joseph Priestley discovered the gas nitrous oxide.  Initially, people thought this gas to be lethal, even in small doses, like some other nitrogen oxides.  However, in 1799, British chemist and inventor Humphry Davy decided to find out by experimenting on himself. To his astonishment he found that nitrous oxide made him laugh, so he nicknamed it "laughing gas.” In 1800 Davy wrote about the potential anesthetic properties of nitrous oxide in relieving pain during surgery, but nobody at that time pursued the matter any further.

American surgeon and pharmacist Crawford Long is known as the inventor of modern anesthetics in the West.  Long noticed that his friends felt no pain when they injured themselves while staggering around under the influence of ether.  He immediately thought of its potential in surgery.  Conveniently, a participant in one of those "ether frolics,” a student named James Venable, had two small tumors he wanted excised.  But fearing the pain of surgery, Venable kept putting the operation off.  Hence, Long suggested that he have his operation while under the influence of ether.  Venable agreed, and on March 30, 1842 he underwent a painless operation.  However, Long did not announce his discovery until 1849.

American dentist Horace Wells conducted the first public demonstration of an inhalational anesthetic at the Massachusetts General Hospital in Boston in 1845.  However, the nitrous oxide was improperly administered and the patient cried out in pain.

On October 16, 1846, another Boston dentist, William Thomas Green Morton, was invited to Massachusetts to demonstrate his new technique for painless surgery using ether as the anesthetic.  After dentist Morton induced the anesthesia, surgeon John Collin Warren removed a tumor from the neck of Edward Gilbert Abbott.  This occurred in the surgical amphitheater now called the Ether Dome.  The previously skeptical surgeon Warren was impressed and stated, "Gentlemen, this is no humbug."  This groundbreaking event was the first public demonstration of the use of ether as an anesthetic.

In a letter to Morton shortly thereafter, physician and writer Oliver Wendell Holmes, Sr. proposed naming the state produced "anesthesia," and the procedure an "anesthetic.”  News of the successful anesthetic spread quickly by late 1846 - and the use of anesthesia soon spread around the world for both dental and medical purposes. 

Anesthetic being administered today prior to an operation.

 

Today, many types of anesthesia can be administered to keep a patent comfortable and pain-free during surgery, medical procedures, or tests. 

General anesthesia is used for major operation, such as a knee replacement or open-heart surgery, and causes the patient to lose consciousness.

IV/Monitored sedation is often used for minimally invasive procedures like colonoscopies.  The level of sedation ranges from minimal - drowsy but able to talk - to deep unconsciousness.

Regional anesthesia is often used during childbirth and surgeries of the arm, leg, or abdomen.  It numbs a large part of the body, but the patient remains aware.

Local anesthesia is for procedures such as getting stitches or having a mole removed.  It numbs a small area, and the patient is alert and awake.

Over our lifetimes, both Pat and I have had ample opportunity to experience anesthesia of all types.  Thank you so much to the inventors!

Viagra

One of the most prescribed drugs in the world, Sildenafil, sold under the brand name Viagra, was originally developed to help treat high blood pressure and angina, a heart condition that constricts the vessels that supply the heart with blood. 

In 1989, sildenafil was synthesized by a group of pharmaceutical chemists wording at Pfizer's Sandwich, Kent, research facility in England.  Phase I clinical trials showed that the drug had little effect on angina, but it could induce increased frequency and potency of erections in male participants.  While at the time this may have been a disappointment to those who developed it, their accidental invention resulted in a gold mine for Pfizer.

Pfizer decided to market it for erectile dysfunction, rather than for angina; this decision became an often-cited example of drug repositioning.  The drug was patented in 1996, and approved for use in erectile dysfunction by the FDA on March 27, 1998, becoming the first oral treatment approved to treat erectile dysfunction in the United States, and offered for sale later that year.  It soon became a great success; annual sales of Viagra peaked in 2008 at $1.934 billion.

 

Viagra, the familiar little blue pill for erectile disfunction.

Teva Pharmaceuticals was the first company to make generic Viagra.  And ever since it originally launched in December 2017, more manufacturers have come to the table.

In 2020, Viagra was the 183^rd most commonly prescribed medication in the United States, with more than 2 million prescriptions.  It is taken by mouth or by injection into a vein.  Onset is typically within twenty minutes and lasts for about two hours.

Let’s just say that I have some familiarity with this drug.

Botox

Botox is a drug made from a toxin produced by the bacterium Clostridium botulinum.  It's the same toxin that causes a life-threatening type of food poisoning called botulism.  Doctors use it in small doses to treat health problems, including: temporary smoothing of facial wrinkles and improving your appearance.

Botulism is a rare but very serious illness that transmits through food, contact with contaminated soil, or through an open wound.  Without early treatment, botulism can lead to paralysis, breathing difficulties, and death.  Certain food sources, such as home-canned foods, provide a potent breeding ground.  About 145 cases of botulism are reported every year in the United States; about 3 - 5% of those with botulism poisoning die.

The discovery of the botulism toxin dates all the way back to 1820s Germany, when a scientist named Dr. Justinus Kerner was investigating the death of several people who died as a result of food-borne botulism.  More specifically, Dr. Kerner was studying the neurological effects of the poison - muscle weakness, difficulty swallowing, drooping eyelids and in some cases, paralysis and respiratory failure.  His research not only helped understand prevention and treatment, but also planted the seed for using the toxin therapeutically, as we do today.

By the 1940s, botulinum toxin was considered to be the most dangerous substance in the world, and the U.S. was researching it for use as a biological weapon during World War II.

In the 1950s and 60s, scientists were able to purify botulinum toxin, and research began into using the purified toxin for therapeutic purposes.  It was used as early as the 1960s to treat strabismus, or crossed eyes.  By the late 1980s, it was FDA-approved and used regularly to treat crossed eyes and eyelid spasms.

Its cosmetic advantages were discovered accidentally in 1987 by ophthalmologist Dr. Jean Carruthers who noticed that when patients were treated for eyelid spasms using the toxin, there was a bonus side effect of reduced forehead lines.  She published a paper on the subject in 1992, and once word got out, Botox (as it was now called) became the hottest ticket in town.

Botox shots block certain chemical signals from nerves that cause muscles to contract.  The most common use of these injections is to relax the facial muscles that cause frown lines and other facial wrinkles.

Botox was FDA approved for cosmetic use in 2002, and since then, has consistently remained the number one nonsurgical procedure in the U.S., with over one million people utilizing it for its rejuvenating anti-aging effects each year.  Botox has also been FDA approved to treat several medical issues, including hyperhidrosis (excessive sweating), chronic migraines, and overactive bladder.

Patient about to receive a shot of Botox.

 

Neither Pat nor I have ever used Botox, having long ago accepted our “life experience” wrinkles.

Smoke Detector

Smoke detectors are so commonplace in homes and businesses that they’re easy to overlook.  But their invention has saved millions of lives, and having a working smoke detector in the home decreases the risk of dying in a fire by more than half.

In the 1930s, Swiss scientist Walter Jaeger accidentally invented the smoke detector when he was trying to invent a sensor to detect poison gas.  His sensor device was supposed to move a meter when the poison gas entered it and altered the electrical current inside.  But when he tried to get his device to work with the poison gas, nothing happened.  So, he lit a cigarette and pondered what to do next… and the detector went off (moving the meter) when it detected his cigarette smoke.  The first modern smoke detector was born.

Jaeger’s smoke detector employed a small, harmless amount of radioactive material to ionize the air in a sensing chamber; the presence of smoke affected the flow of the ions between a pair of electrodes, which produced a weak signal to trigger an alarm.

In 1939, another Swiss scientist, Ernst Meili, improved upon Jaeger’s invention.  He invented a device to amplify the weak signal made by the smoke detector’s mechanism sufficient to confidently trigger the alarm.  This, in turn, made the ionization chamber smoke detector more sensitive and more effective.

In 1963, the Atomic Energy Commission (AEC) granted the first license to distribute smoke detectors using radioactive material.  These detectors were mostly used in public buildings including warehouses and factories during the 1960s.  In 1969, the AEC first allowed homeowners to use smoke detectors - without the need for a license.  By the 1970s, ionization chamber smoke detectors in homes became commonplace.

Today, besides ionization chamber smoke detectors, there are photoelectric smoke detectors that use a beam of light inside the device to detect smoke.  When smoke enters the detector, it disrupts the beam of light and, thus, triggers the alarm.

Nine in 10 homes have smoke detectors today.  Between 80 and 90% of them are ionization chamber smoke detectors.

Smoke detectors are usually housed in plastic enclosures, typically shaped like a disk about six inches in diameter and one inch thick.  Smoke detectors operate on a 9-volt battery.

Household smoke detectors are typically mounted on the ceiling.

 

Household smoke detectors generally issue an audible or visual alarm from the detector itself or several detectors if there are multiple devices interlinked.  Household smoke detectors range from individual battery-powered units to several interlinked units with battery backup.  With interlinked units, if any unit detects smoke, alarms will trigger at all of the units. This happens even if household power has gone out.

Smoke detectors in large commercial and industrial buildings are usually connected to a central fire alarm system.

In our current home, built in 1995, there are four ceiling-mounted, interlinked ionization chamber smoke alarms, that operate on the home’s 120-volt power source with a 9-volt battery backup.  Thankfully, we have had no fire or smoke issues, but have suffered the inconvenience several times of having to replace a battery in a “chirping” detector in the middle of the night.

Laminated Safety Glass

Safety glass is glass with additional features that make it less likely to break, or less likely to pose a threat when broken.  Common designs include toughened glass (also known as tempered glass), wire mesh glass, and laminated glass. 

Toughened glass was invented in 1874 by Francois Barthelemy Alfred Royer de la Bastie.  Tempered glass is often used today in car windows, shower doors, glass tables, and other installations where increased safety standards are necessary.  While the manufacturing process does make tempered glass more resistant to force, it is not unbreakable.  If the glass is broken, it shatters into pebbles reducing the risk of serious injury.

Wire mesh glass was invented in 1892 by Frank Shuman.  The wire mesh acts as a reinforcement.  If the glass breaks due to impact, the pieces of glass are held by wire reinforcement in position.  Wired Glass is used today in partitions and windows of public buildings, schools, hotels, and institutions.  Usually, wired glass is used in windows of routes to the fire escape, this helps in increasing the time required for evacuating people in a situation of fire or other emergencies.

Laminated glass was invented in 1903 by the French chemist Edward Benedictus, inspired by a laboratory accident:  a glass flask coated with the plastic cellulose nitrate was accidentally dropped.  When Benedictus looked down, he noticed that rather than breaking into a million little pieces, the glassware had actually just cracked slightly while maintaining its shape.  After looking into it a bit further, the scientist learned that what had kept the glass together was the cellulose nitrate coating the inside of the glass - and thus, the idea of laminated safety glass was created.

In 1909 Benedictus filed a patent, after hearing about a car accident where two women were severely injured by glass debris.  In 1911, he formed the Triplex Glass Company, which fabricated a glass-plastic composite windshield to reduce injuries in car accidents.  Production of Triplex glass was slow and painstaking, so it was expensive; it was not immediately widely adopted by automobile manufacturers.  But laminated glass was widely used in the eyepieces of gas masks during World War I.  

In 1912, the laminated safety glass process was licensed to the English Triplex Safety Glass Company. Subsequently, in the United States, both Libbey-Owens-Ford and Du Pont, with Pittsburg Plate Glass, produced Triplex glass.

In 1927, Canadian chemists Howard W. Matheson and Frederick W. Skirrow invented the plastic polyvinyl butyral (PVB).  By 1936, United States companies had discovered that laminated safety glass consisting of a layer of PVB between two layers of glass would not discolor and was not easily penetrated during accidents.  The interlayer kept the layers of glass bonded even when broken, and its toughening prevented the glass from breaking up into large sharp pieces.  This produced a characteristic "spider web" cracking pattern (radial and concentric cracks) when the impact was not enough to completely pierce the glass.

Within five years, the new laminated safety glass had substantially replaced its predecessor.

Laminated safety glass consists of two pieces of glass bonded with a vinyl interlayer, usually PVB.

 

Today, besides automobile windshields, laminated glass is normally used when there is a possibility of human impact or where the glass could fall if shattered.  Store windows, doors, and skylights for example, are typically made of laminated glass.  Buildings that have glass floors also use laminated glass to prevent breakage from all the foot traffic.  The material is even be made bullet proof, so it may be found in police cars and stations.  In geographical areas requiring hurricane-resistant construction, laminated glass is often used in exterior storefronts, weather protection facades, and windows. 

The PVB interlayer also gives laminated glass a much higher sound insulation rating, and also blocks most of the incoming UV radiation (88% in window glass and 97.4% in windscreen glass).

Pat and I have both experienced car windshield damage from flying objects (rocks?).  Sometimes the damaged area was small enough to be repaired; other times the entire windshield had to be replaced.  But in all cases, the laminated safety glass did its job!

Dynamite

Though the explosive substance nitroglycerin was invented by Ascanio Sobrero, it was Alfred Nobel who used it to make dynamite.

Nitroglycerin was invented in 1847 by Italian chemist Ascanio Sobrero, who combined glycerol with nitric and sulfuric acids to produce an explosive compound.  It was far more powerful than gunpowder, and more volatile.  Sobrero was opposed to its use, but his lab mate, Swedish chemist and engineer Alfred Nobel, saw potential for creating profitable explosives and weapons. 

Nitroglycerin became a commonly used explosive, but it was quite unstable and prone to spontaneous explosions, making it difficult for scientists to experiment with. 

In the early 1860s, Alfred Nobel, along with his father and brother Emil, experimented with various combinations of nitroglycerin and black powder.  Nobel came up with a solution of how to safely detonate nitroglycerin by inventing the detonator, or blasting cap, that allowed a controlled explosion set off from a distance using a fuse.  In 1863, Nobel performed his first successful detonation of pure nitroglycerin, using a blasting cap. 

On September 3, 1864, while experimenting with nitroglycerin, Emil and several others were killed in an explosion.  After this, Alfred continued work in a more isolated area.

Despite the invention of the blasting cap, the instability of nitroglycerin rendered it useless as a commercial explosive.  One day he was working with nitroglycerin when a vial accidentally fell to the floor and smashed.  But it didn’t explode, due to the contact it had made with a pile of sawdust, which helped to stabilize it.  Nobel later perfected the mixture by using kieselguhr, a form of silica, as a stabilizing substance.

Nobel patented his new explosive in 1867.  One thousand times more powerful than black powder, dynamite rapidly gained wide-scale use as a more robust alternative to the traditional black powder explosives.  It allowed the use of nitroglycerine's favorable explosive properties while greatly reducing its risk of accidental detonation.

Nobel tightly controlled the patents, and unlicensed duplicating companies were quickly shut down.  He originally sold dynamite as "Nobel's Blasting Powder" but decided to change the name to dynamite, from the Ancient Greek word dýnamis, meaning "power.”

Laminated safety glass consists of two pieces of glass bonded with a vinyl interlayer, usually PVB.

 

In addition to its limited use as a weapon, dynamite was used initially - and still is today - in the construction, mining, quarrying, and demolition industries.  Dynamite has expedited the building of roads, tunnels, canals, and other construction projects worldwide.

Today Alfred Nobel’s name is well known, but more for prizes of achievements and peace than for explosives. The Nobel Prizes are five separate annual prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind" in five categories:  physics, chemistry, physiology or medicine, literature, and peace.

Neither Pat nor I have ever had direct connection to dynamite, but we certainly have benefited from all its applications to construction projects.

Vulcanized Rubber

Vulcanization is a range of processes for hardening rubber.

The Aztec, Olmec, and Maya of Mesoamerica are known to have made rubber using natural latex - a milky, sap-like fluid found in some plants.  These ancient rubber makers mixed latex with juice from morning glory vines, which contains a chemical that makes the solidified latex less brittle.  Mixing up rubber using different proportions of the two ingredients, led to rubber products with different properties.  They used rubber to make balls (for ceremonial games in stonewalled courts), sandal soles, rubber bands, and waterproof containers.

Skip to the 19^th century:  The problem with natural rubber is that it is not useful in its unaltered state.  In hot temperatures, rubber melts and becomes sticky.  In cold temperatures, it gets rigid and brittle. 

Early rubber tube tires would grow sticky on a hot road.  Debris would get stuck in them and eventually the tires would burst. 

In the 1830s, American inventor Charles Goodyear, was working to improve those tube tires.  He tried heating up rubber in order to mix other chemicals with it.  This seemed to harden and improve the rubber, though this was due to the heating itself and not the chemicals used.  Not realizing this, he repeatedly ran into setbacks when his announced hardening formulas did not work consistently.  One day in 1839, when trying to mix rubber with sulfur, Goodyear accidentally dropped the mixture into a hot frying pan.  To his astonishment, instead of melting further or vaporizing, the rubber remained firm and, as he increased the heat, the rubber became harder.  Over the next five years, Goodyear worked out a consistent system for this hardening and discovered vulcanization:  the treatment of rubber with heat, and originally sulfur, to bring it to a molecular state which gives the rubber better strength, elasticity, and durability.  He patented the process in 1844.

His discovery started decades of successful rubber manufacturing, as rubber was adopted to multiple applications, including automobile tires and footwear.

Twenty-four years after Goodyear’s death, in 1898, the Goodyear Tire and Rubber Company was named after him.

1951 advertisement for Goodyear vulcanized automobile tires.

 

In 1912, George Oenslager, an American chemist, invented an advanced method of vulcanizing rubber that is still used today.  He discovered a derivative of aniline (a colorless oily liquid present in coal tar) that accelerated the vulcanization of rubber with sulfur, which greatly increased the cost effectiveness of rubber. 

These days natural rubber is obtained from rubber trees that require a hot, damp climate.  More than 90% of the world's natural rubber supply comes from mainland Southeast Asia. 

Today, more than one billion automobile tires are manufactured worldwide on an annual basis.  Vulcanized rubber is also used to produce rubber hoses, shoe soles, insulation, vibration dampers, erasers, hockey pucks, shock absorbers, children’s toys, conveyor belts, rubber-lined tanks, bowling balls, and more.  Most rubber products are vulcanized as this massively improves their lifespan, function, and strength.

Together with almost everyone else in the world today, Pat and I are, and have been, regular users of vulcanized rubber products.

Stainless Steel Cutlery

Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as nickel, carbon, and other nonmetals to obtain specific desired properties. 

Over the course of the 19^th century many experiments were made with iron and steel to develop new alloys and investigate their properties.  By the early 1900s, metallurgists in Germany, France and the United States were getting close to developing what we now know as stainless steel.

In 1908, English metallurgist Harry Brearley, at Sheffield’s Steelworks, was given a task by a rifle manufacturer who wanted to prolong the life his gun barrels which were eroding away too quickly from excessive wear on the internal surface of the barrel.

Brearley set out to create erosion - resistant steel by developing steel alloys containing chromium, which was known to raise the material's melting point, as compared to the standard carbon steels.  He made several variations of alloys, ranging from 6% to 15% chromium, with different measures of carbon.  On August 13, 1913, Brearley created steel with 12.8% chromium and 0.24% carbon, which is thought to be the first ever stainless steel - and proved to be the solution to the gun barrel problem.  The discovery was announced two years later in a January 1915 newspaper article in The New York Times.

In his experiments, Brearley etched his steel samples with nitric acid for identification to examine them under a microscope.  He found that his new steel resisted these chemical attacks, and so he tested the sample with other agents, including lemon juice and vinegar.  Brearley was astounded to find that his alloys were still highly resistant, and immediately recognized the potential of his new steels for food-grade cutlery, saucepans, and other kitchen equipment.

Up to that time, carbon-steel knives were prone to unhygienic rusting if they were not frequently polished, and only expensive sterling silver or electroplated nickel silver cutlery was generally available to avoid such problems.  He foresaw the elimination of nightly washing, polishing and putting away of the silverware that was then required.

Stainless steel cutlery is widely used today.

 

Brearley struggled to win the support of his employers for this accidental new product application, so he teamed up with local cutler R. F. Mosley.  Brearley was going to call his steel “Rustless Steel” but Ernest Stuart, Cutlery Manager at Mosley's Portland Works, called it “Stainless Steel” after testing the material with vinegar, and the name stuck. 

Virtually all research projects into the further development of stainless steels were interrupted by World War I (1914-1918), but efforts were renewed in the 1920s.  Brearley’s successor, Dr. W. H. Hatfield, is credited with the development, in 1924, of an alloy of stainless steel, which in addition to chromium, included nickel - and is still used widely today.

Harry Brearley’s invention brought affordable cutlery to the masses.

Major technological advances in the 1950s and 1960s allowed the production of large tonnages of stainless steel at an affordable cost.  In addition to cutlery, cookware, kitchen sinks, and other culinary uses, stainless steel is used today in surgical tools and medical equipment, surgical implants, temporary dental crowns, buildings, bridges, and transportation applications.

Kitchen-wise, Pat and I have lived for a long time in the stainless-steel generation with all the products mentioned. 

Dry Cleaning

Dry cleaning is any cleaning process for clothing and textiles using a solvent other than water.

The earliest records of professional dry cleaning go all the way back to the Ancient Romans.  For instance, dry cleaning shops were discovered in the ruins of Pompeii, a Roman city buried by the eruption of Mount Vesuvius in 79 AD.  Those cleaners, known as fullers, used a type of clay known as fuller’s earth along with lye and ammonia (derived from urine) in order to remove stains such as dirt and sweat from clothing.  That process proved pretty effective for any fabric too delicate for normal washing or stains that refused to budge.  

As for more modern methods, the biggest revolution in dry cleaning came in the early 19^th century.  Traditionally, textile maker Jean Baptiste Jolly of France is generally named the father of modern dry cleaning.  The story goes that in 1825, a careless maid accidentally knocked over a lamp and spilled turpentine on a dirty tablecloth.  Jolly noticed that once the turpentine dried, the stains that had marred the fabric were gone.  He conducted an experiment where he bathed the entire tablecloth in a bathtub filled with turpentine and found that it came clean once it dried.  Jolly used this method when he opened the often claimed first modern dry-cleaning shop, “Teinturerier Jolly Belin,” in Paris in 1845.

However, a patent for a process called “dry scouring” had been filed with the U.S. Patent Office in 1821, four years before Jolly’s discovery. A man by the name of Thomas Jennings was a clothier and a tailor in New York City, and the first African American to be granted a patent in the United States.

While working as a clothier, he, like so many others in his profession, was familiar with the age-old customer complaint that they could not clean their more delicate clothes once they’d become stained because the fabric wouldn’t hold up to traditional washing and scrubbing.  Jennings, thus, began experimenting with different cleaning solutions and processes before discovering the process he named “dry scouring.”  His method was a hit and not only made him extremely wealthy, but allowed him to buy his wife and children out of slavery, as well as fund numerous abolitionist efforts.

The exact method Jennings used has been lost to history, as his patent was destroyed in an 1836 fire.  After Jennings, other dry cleaners during the 19^th century used things like turpentine, benzene, kerosene, gasoline, and petrol as solvents in the process of dry-cleaning clothes.  These solvents made dry cleaning a dangerous business.  Turpentine caused clothes to smell even after being cleaned, and benzene could be toxic to dry cleaners or customers if left on the clothes.  But all of these solvents posed the bigger problem of being highly flammable.  The danger of clothes and even the building catching fire was so great that most cities refused to allow dry cleaning to occur in the business districts.  

This led to dry cleaners searching for a safer alternative. Chlorinated solvents gained popularity in the early 20^th century, after World War I. They removed stains just as well as petroleum-based cleaners without the risk of causing the clothes or factories to catch fire.  That also meant dry cleaners could move their cleaning facilities back into cities and eliminated the need to transport clothes back and forth between two locations.

By the mid-1930s, the dry-cleaning industry had started to use tetrachloroethylene as the solvent.  It has excellent cleaning power and is nonflammable and compatible with most garments. 

Typical dry cleaning store rack of garments.

 

Since the 1990s, there has been concern that tetrachloroethylene may be a toxic chemical that causes cancer.   Studies are ongoing, but the use of the chemical in dry cleaning is still common.

Years ago, when I worked for a living and wore suits every day, I was a regular user of dry-cleaning services.  But in retirement, I have not had to use dry cleaning.   Pat has long been concerned about the chemicals used in dry cleaning, and therefore has avoided the service

Conclusions

This concludes my blog on fifteen accidental inventions that changed the World.  This also concludes my four-part series on inventions.  Just reminding the reader that the previous three covered: the top 10 inventions that changed the world (04/18/2023), accidental inventions that are common household items (06/05/2023), and ten more accidental inventions that are common household items (06/14/2023).  I realize that I omitted a few inventions in each category, and may have to revisit them at another time.

Pat and I really enjoyed talking about how all these inventions affected us!