In 1742, Anders Celsius made a "reversed" version of the modern Celsius temperature scale. In this scale, zero was the boiling point of water and 100 was the melting point of ice. In his paper "Observations of two persistent degrees on a thermometer," he wrote about his experiments. He showed that the melting point of ice was basically unaffected by air pressure. Ice would turn into water at the same temperature, whether it was at sea level or on a mountain. This was not the case for the boiling point of water. It would boil easier with less pressure (on a mountain). He decided that zero on his temperature scale (water's boiling point) would be set at the standard barometric pressure at sea level. This pressure is known as one atmosphere. In 1954, Resolution 4 of the 10th CGPM (the General Conference on Weights and Measures) set what exactly is one standard atmosphere ().
In 1744, the year Anders Celsius died, the famous Swedish botanist Carolus Linnaeus (1707–1778) used a reversed version of Celsius's scale when he bought his first thermometer. This had a scale where zero represented the melting point of ice and 100 represented water's boiling point, similar to what we use it today. His custom-made "Linnaeus thermometer", to use in his greenhouses, was made by Daniel Ekström, then Sweden's leading maker of scientific instruments. Ekstöm's workshop was in the basement of the Stockholm observatory. As often happened in this age before modern communications, many physicists, scientists, and instrument makers are given credit with independently making the same measurement scale; among them were Pehr Elvius, the secretary of the Royal Swedish Academy of Sciences (which had an instrument workshop), who Linnaeus had also talked to; Christin of Lyons; Daniel Ekström, the instrument maker; and Mårten Strömer (1707–1770) who had studied astronomy under Anders Celsius.
The first known document reporting temperatures in this modern "forward" Celsius scale is the paper "Hortus Upsaliensis", dated 16 December 1745, that Linnaeus wrote to a student of his, Samuel Nauclér. In it, Linnaeus reported the temperatures inside the orangery at the Botanical Garden of Uppsala University:
...since the caldarium (the hot part of the greenhouse) by the angle of the windows, merely from the rays of the sun, obtains such heat that the thermometer often reaches 30 degrees, although the keen gardener usually takes care not to let it rise to more than 20 to 25 degrees, and in winter not under 15 degrees...
For the next 204 years, the scientific and thermometry communities worldwide called this scale the "centigrade scale". Temperatures on the centigrade scale were often reported as "degrees" or "degrees centigrade". The symbol for temperature values on this scale was °C (in several formats over the years). Because the name "centigrade" was also the Spanish and French language name for a unit of angular measurement (one-hundredth of a right angle) and had a similar meaning in other languages, the term "centesimal degree" was used when very precise, clear language was required for international communication, such as by the International Bureau of Weights and Measures (BIPM). The 9th CGPM (General Conference on Weights and Measures) and the CIPM (International Committee for Weights and Measures) officially decided to use "degree Celsius" (symbol: °C) in 1948.
There were three reasons for the decision in 1948 to use the word "Celsius":
It would take nearly two decades however, for school textbooks to change from "centigrade" to "Celsius", and many people today still use the old name.
Fahrenheit
Fahrenheit (more precisely, a degree Fahrenheit) is a unit of measurement used to measure temperature. The conversion rate to Celsius is C= 5/9 x (F − 32). The degree Fahrenheit is abbreviated °F.
This temperature scale was made in 1724 by a German scientist named Daniel Gabriel Fahrenheit. In the twentieth century, the unit became less used, and the degree Celsius more used. Fahrenheit is still often used in the United States. In the United Kingdom, Fahrenheit is used on some websites, and on weather forecasts. The main reason for this is that the older population is more familiar with Fahrenheit.
The degree Fahrenheit is considered by many to be old fashioned and outdated way of measuring temperature. The degree Celsius has largely replaced Fahrenheit's use. However, Fahrenheit is understood by many ordinary people, whereas the Celsius scale is more abstract. The needs of ordinary people are often quite different to the needs of professional scientists and technicians.
Overall, the use of the degree Fahrenheit is in decline throughout most of the world, with the USA being the main exception.
On the Fahrenheit scale, water freezes at 32° and boils at 212°.
Agent
An agent is a person who acts on behalf of another person, or a representative of an agency.
Agent can also mean:
In science:
In fiction:
Anthrax
Anthrax, or splenic fever, is a disease. Both humans and other animals can get it. It is caused by the bacterium bacillus anthracis. It is common with even-toed ungulates (some hoofed creatures, like camels and giraffes). The spores of the bacteria can live for hundreds of years. Humans usually catch the disease from animals. It is usually not passed from one human to another. Anthrax can be treated with antibiotics. There is also a vaccine against it. If not treated, anthrax often leads to death.
There are 89 different strains (kinds) of anthrax. One of them, the Ames strain, was used against the United States in 2001 as a biological weapon.
On April 2, 1979, there was a leak at one of the plants just outside of Sverdlovsk that made anthrax during the Cold War. 94 people were infected and 64 of those people died. The USSR blamed the deaths on another strain of anthrax that the people caught by digesting infected meat. However, later it was revealed that the outbreak was caused by an accidental release of the bacteria from a nearby plant which developed biological weapons for the USSR.
In September 2001, several letters containing anthrax were mailed to several USA media companies and senators. The attacks were linked to the September 11 attacks which occurred a few days before the start of the attack.
There were many cases of fake powder being found in envelopes.
Napoleon
Napoleon Bonaparte () was a French politician and army leader who ruled France from 1799 to 1814 and for a short period (the "Hundred Days") in 1815. He became Emperor of the French and King of Italy as Napoleon I. He had power over most of Europe at the height of his power, and his actions shaped European politics in the early 19th century.
Bonaparte was born in Corsica into a noble family. He learned the Corsican language first before learning French. He moved to mainland France and trained to become an army officer. He became an important army leader during the First French Republic, helping to stop the countries that wanted to end the French Revolution. In 1799, he overthrew the government and took control of France for himself (a "coup d'état"). At first his title was Consul. Five years, he was made Emperor of France. In the first ten years of the nineteenth century, the French Empire under Napoleon waged the Napoleonic Wars. Every European great power joined in these wars. After a number of victories, France became very important in continental Europe. Napoleon increased his power by making many alliances. He also made other European countries into French client states by letting his friends and family members rule them.