When I taught basic chemistry, at the Industrial Technical Institute in Arezzo town (Italy), one of the first lessons of the course was dedicated to illustrating a laboratory experience that students would perform at home. It was the formation of sodium chloride crystals from a salt solution. After about a week each student brought to school his saucer where they had grown small but regular cubic crystals of salt.
A few miles from Ribe in Denmark has been rebuilt a Viking village where the living conditions of the Viking era have been recreated. Crafts, agricultural activities, animal breeding are reproduced that make the visitor take a leap into the past, in that civilization that dominated in the northern Europe between 700 and 1100.
In the Moesgard Museum in Aarhus, Denmark among the collection of prehistoric finds is the main attraction which is the bimillion-year-old Grauballe Man, whose extraordinarily preserved body was found in 1952 near the village of Graubelle, 35 km from the city of Aarhus, in a swamp in central Jutland by a peat-seeker. No jewelry or clothing were found near the body. The mummy is very well preserved. The fingers are in good condition, so much so that they can get fingerprints. Beard, hair and skin are excellently preserved, but the colors have been altered by time and prolonged immersion in the swamp. Nail and hair keratin has taken on a reddish colou for the biochemical conditions of the environment. The bones are almost dissolved due to the acidity of the environment that has soluble the mineral component of the bones. . The skin has taken on a very dark color, almost black, which like a parchment seems to cover the bones. The body had been preserved for a process similar to tanning, caused by the umic acid and the iron contents of the peat water that had made the skin very resistant and prevented rotting.
Archibald Scott Couper wrote in 1857 a note about his new chemical theory that was presented by Jean Baptiste Dumas at the French Academy and published in Comptes rendus. His presentation was followed by the publication of an essay entitled “Sur Une Nouvelle Theorie Chimique” in Annales de chimie et de physique. The article appeared soon after in the British magazine Philosophical Magazine entitled “On a New Chemical Theory” which contained some important changes from the version French. Almost simultaneously, Friedrich August Kekulé’s article “The Constitution and Metamorphoses of Chemical Compound and the Chemical Nature of Carbon” appeared in Annalen der Chemie und Pharmacie, in which he came to the same conclusions as Couper.
In another article on my blog I described the human and scientific events that made A.S.Couper so extraordinary and interesting. I reserved the precedence of Couper over Kekulè because he appears in this scientific story the most unlucky character, but also more brilliant. After writing his revolutionary essay Couper will soon disappear from the scientific life overwhelmed by his problems. We will no longer remember him. Only Kekulè, on the other hand, will take credit for the discoveries made, and even then famous, it will later become one of the greatest chemists of the nineteenth century.
In the history of Organic Chemistry, to the German chemist Friedrich August Kekulé von Stradonitz (1829 – 1896) is reserved for a pre-eminent place. In 1858 he wrote an article listing two fundamental properties of the carbon atom: valence four and the ability of carbon atoms to bind together. In 1865 he published another paper in which he defined the hexagonal structure of the benzene molecule. These discoveries gave an extraordinary boost to the chemistry of the nineteenth century. Today they constitute the axioms of organic chemistry.
But in the same year 1858, a few weeks after the publication of Kekulè and in a completely independent way, another Scottish chemist Archibald Scott Couper (1831-1892) at only twenty-seven years old published an article “On a new chemical theory ” with the same conclusions to which Kekulè had arrived. The life of this chemist is as interesting as it is tragic. He was born in a small village a few miles from Glasgow in 1831. He was the only surviving son of Archibald Couper, a large cotton weaving plant owner that employed more than 600 workers. Of unsteady health, he had a good and scrupulous upbringing at home. In 1851 he began his undergraduate studies at Glascow in Latin and Greek, traveled to Germany, then continued his studies at the University of Edinburgh in philosophy, logic, metaphysics and moral philosophy. So far there are no references in his notes to chemistry studies.
.
Our trip at Mendeleev Museum starts from Saint Petersburg University in via Mendeleevskaya Liniya, where at the beginning of the Boulevard, we are welcomed by the statue of Mikhail Lomonosov Vasilevic 1708-1765 writer, poet, Russian chemist and physicist. Passing the entrance of the University , on the ground floor, directly left, you enter the apartment of Mendeleev. Dott.ssa Natalia , chemist , there acts as a guide. We are the only visitors.
Yosemite Valley
Yosemite National Park is located in the Sierra Nevada in California. It has an area of 3,027 Km2, is as big as the region of Val d’Aosta (Italy) . One of the most beautiful parts of the Park is the Yosemite Valley along which flows the Merced River. The white granite cliffs that surround this canyon , 13 km long , are among the most beautiful on the planet.
At the center of the logo of the American Chemical Society, under the Eagle, there is a strange object made from five balls joined together. But what does it represent? And why is it so important to be included in the logo of one of the most prestigious and oldest chemical society? (Its Foundation is of 1876)
The Logo of American Chemical Society
in the years ‘ 60 of the last century China was shaken by a tragic political movement led by Mao Zedong , leader of the country. It was called “cultural revolution” and had protagonist students and lower Communist Party cadres , that were inspired by the contained in “Red Book”, drafted by the same Mao. The victims of the movement were intellectuals and teachers who were subjected to a process of re-education “and suffered abuse of all kinds. Universities and schools stopped their activity for a few years.
In China has spread the natural medicine that makes use of the world’s plant and animal products. Especially in Hangzhou City, capital of the Chinese province of Zhejiang, one of the seven ancient capitals of China, focuses this ancient medical practice. The Western Lake made town of Hangzhou famous all over the world, is also known for local products, like silk, and green tea.
