Category Scientists & Inventions

What was invented by DF Arago in 1820?

On September 25, 1820, French physicist Francois Arago announced his discovery of an occurrence of electromagnetism. This was just one of Arago’s many contributions as he spent a lifetime for the progress of science.

It isn’t often that we come across a person who contributes significantly to a number of different fields. Such polymaths – individuals whose knowledge encompasses a wide range of subjects – have always been rare. Frenchman Dominique Francois Jean Arago was one such person in this world, as he donned the hat of a physicist. mathematician, astronomer, and politician in an eventful life.

Born in 1786 in Estagel, Roussillon, France, Arago was one of 11 children. Educated at the Municipal College of Perpignan, Arago was drawn towards mathematics from a young age. He was admitted to the Ecole Polytechnique in Paris, where he succeeded French mathematician Gaspard Monge as the chair of Analytic Geometry at the young age of 23.

Love for optics

He made his first major contributions to science in the decade that followed. Working with French engineer Augustin-Jean Fresnel, Arago was able to show that while two rays polarised in a plane can interfere with each other, two beams of light polarised perpendicular to each other cannot interfere with each other. This research led to the discovery of the laws of light polarisation.

In 1820, Arago briefly interrupted his optical work to significantly expand on electromagnetic theories. Having been invited to Geneva to witness the experiments of Danish physicist Hans Christian Oersted linking electricity to magnetism, Arago was instantly converted and developed a huge interest in the subject.

Apart from repeating the Geneva experiments at the Paris Academy, Arago also experimented on his own. He was able to demonstrate that by passing an electric current through a cylindrical spiral of wire, it could be made to behave like a magnet. The temporary magnetisation allowed it to attract iron filings, which then fell off when the current ceased. He announced this occurrence of electromagnetism on September 25, 1820.

Electromagnetic induction

Soon after, Arago discovered the principle of the production of magnetism by rotation of a nonmagnetic conductor. He was able to show that the rotation of a nonmagnetic metallic substance like copper created a magnetic effect as it produced rotation in a magnetic needle suspended over it. It was another decade before English scientist Michael Faraday explained these using his theory of electromagnetic induction in 1831.

Arago served as the director of the Paris Observatory from 1830. As an astronomer, he was among the first to explain the scintillation of stars using interference phenomena. He was also able to provide vital stimulus to young astronomers, including Frenchman Urbain Le Verrier.

“With the point of his pen”

In 1845, Arago suggested to his protege that he investigate the anomalies in the motion of Uranus. These investigations resulted in Le Verriers discovery of Neptune in 1846, and Arago best summed it up when he called Le Verrier the man who “discovered a planet with the point of his pen”. Arago backed Le Verrier in the dispute between Le Verrier and British astronomer John Couch Adams over priority in discovering Neptune and even suggested naming the planet for Le Verrier.

Amidst all his scientific endeavours, Arago also found time to back the ideas of others. Even though French photographer Louis Daguerre was struggling to sell his daguerreotype process, he was able to catch the attention of Arago, who served as the permanent secretary of the French Academy of Sciences.

Advocate for photography

Arago arranged for the first public display of daguerreotypes in January 1839 and used the buzz it created for his lobbying. He was able to get the French Parliament to grant pensions to Daguerre and Isidore Niepce, son of French inventor Nicephore Niepce, so that they could make all the steps of the photographic process public. Arago stated that “France should then nobly give to the whole world this discovery which could contribute so much to the progress of art and science” and the technical details were made public on August 19, 1839 (hence celebrated as World Photography Day).

Optics and the study of light remained close to Arago’s heart and he devised an experiment to prove the wave theory of light. In 1838, he described a test for comparing the velocity of light in air and in water or glass. The elaborate arrangements required for the experiment and his own failing eyesight, however, meant that it wasn’t performed. Shortly before Arago’s death, French physicists Hippolyte Fizeau and Leon Foucault demonstrated the retardation of light in denser media by improving on Arago’s suggested method.

For a man who spent so much of his time pursuing science, he was also able to devote to other causes as a politician. Following the July Revolution of 1830 and up until his death in 1853, Arago was active as a politician, delivering influential speeches regarding educational reform, freedom of press, and the application of scientific thought for progress. After the February Revolution of 1848, he served as the Minister of War and the Navy and used his power to abolish slavery in French colonies. Arago’s influential life highlights the fact that he always possessed the faculty to inspire and stimulate those around him and the public at large, both in the realm of science and in politics.

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Did you know the first antibiotic penicillin was discovered by accident?

Penicillin was discovered by chance by British scientist Alexander Fleming in 1929. Fleming was growing colonies of staphylococcus bacteria, the cause of a number of diseases from boils to pneumonia, in culture plates in his laboratory. One of the plates had not been covered and airborne spores settled in it and formed a mould. Fleming was about to throw away the contents when he noticed that the mould had destroyed the bacteria in the area around it.

He realised that the mould was producing a substance that was lethal to the bacteria. He also realised that the substance could be used to cure diseases caused by the bacteria. As the mould was called Penicillium notatum, he named the unknown substance ‘penicillin’. Ten years later in 1940, Howard Florey and E. B. Chaim managed to isolate penicillin in the laboratory and showed that it could be safely administered by mouth, by injection or applied directly to wounds.

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WHAT WAS INVENTED BY WALTER HUNT?

On July 25, 1854, American inventor Walter Hunt received his patent for a paper shirt collar-“Improvement in shirt collars”. This was one of Hunt’s many inventions, the more popular of which are the safety pin and the sewing machine.

When you use a safety pin or see the paper collar in a shirt do you ever stop to think about how it came to be in the first place? There are many such inventions that silently go about doing their roles effectively, without pomp and fanfare. When it concerns the safety pin or the paper collar, they are probably taking a leaf out of their inventors book. For American inventor Walter Hunt spent a lifetime inventing without becoming a household name despite his successes.

Born in 1796 in the rural part of New York, very little is known about Hunt’s early childhood. His obituary mentions that he was more interested in people and what he could do for them rather than his own welfare, right from childhood. It was a trait that he had throughout his life as he devoted himself to his dear ones, often giving away everything in his possession, even if that meant he didn’t have enough to provide for himself.

Hunt’s first patent

Hunt’s family worked in a textile mill in the town of Lowville. With his ability to provide mechanical solutions to even complex problems, Hunt was able to work with Willis Hoskins, the mill owner, inventing and patenting a machine for spinning flax and hemp. This patent, which they obtained in 1826, was Hunt’s first.

In 1833, Hunt invented a sewing machine that used a lockstitch – the first time an inventor had not tried to replicate a hand stitch with their machine. There’s reason to believe that Hunt never patented it at the time as his daughter talked him out of commercialising the device, warning that its success would leave a lot of seamstresses unemployed.

This meant that the first patent for a lockstitch sewing machine went to American inventor Elias Howe in 1846. In the aftermath, Hunt applied a patent for his sewing machine in 1853. While the Patent Office recognised Hunt’s precedence and he therefore received public credit for the invention. Howe raked in the money as his patent continued to be valid owing to certain technicalities.

Repaying a debt

Between the time he invented and patented his sewing machine, there was once a time when Hunt found himself owing a man a $15 debt. Eager to invent something that would allow him to erase the debt. Hunt is believed to have twisted an ordinary metal wire until he ended up with a device he called the “dress pin”.

Even though the idea wasn’t entirely novel and the concept can even be dated back to the Roman empire, Hunt was able to bring in innovations that made a lasting impact. With a clasp to keep the pin’s point inside a protective case and a spring at one end that forced the other end in place. Hunt’s dress pin had all the features now found today in every safety pin.

Hunt received a patent for his dress pins on April 10, 1849 and sold its rights for just $400 off his own volition. The money helped him repay his debt, even though it was only a minute fraction of the substantial fortune that his invention created.

Muslin and paper

A little over five years later, on July 24, 1854, Hunt received a patent for his paper shirt collar – “Improvement in shirt collars”. He used a base of thin white cotton muslin and pasted very thin white paper on both its sides. These collars could be pressed between heated forms to make the shape of the neck. These collars were then varnished, thereby guarding it against the effects of sweat and also allowing it to be wiped clean with a damp cloth.

Until his death in 1859, Hunt continued to invent and patent devices, which included a knife sharpener, heating stove, ice boat, fountain pen, and a reversible metallic heel for shoes, to name a few. Even though he sold the rights to most of his patents, allowing others to enjoy the financial rewards that his devices brought, he was respected and recognised as someone who had spent his entire lifetime inventing.

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