The History Behind the Invention of Gas Masks

The History Behind the Invention of Gas Masks Inventions that aid and protect the ability to breathe in the presence of gas, smoke or other poisonous fumes were being made before the first use of modern chemical weapons. Modern chemical warfare began on April 22, 1915, when German soldiers first used chlorine gas to attack the French in Ypres. But long before 1915, miners, firemen and underwater divers all had a need for helmets that could provide breathable air. Early prototypes for gas masks were developed to meet those needs. Early Fire Fighting and Diving Masks In 1823, brothers  John and Charles Deane patented a smoke protecting apparatus for firemen that was later modified for underwater divers. In 1819, Augustus Siebe marketed an early diving suit. Siebes suit included a helmet in which air was pumped via a tube to the helmet and spent air escaped from another tube. The inventor founded Siebe, Gorman, and Co to develop and manufacture respirators for a variety of purposes and was later instrumental in developing defense respirators. In 1849, Lewis P. Haslett patented an Inhaler or Lung Protector, the first U.S. patent (#6529) issued for an air purifying respirator. Hasletts device filtered dust from the air. In 1854, Scottish chemist John Stenhouse invented a simple mask that used charcoal to filter noxious gasses. In 1860, Frenchmen, Benoit Rouquayrol, and Auguste Denayrouze invented the Rà ©sevoir-Rà ©gulateur, which was intended for use in rescuing miners in flooded mines. The Rà ©sevoir-Rà ©gulateur could be used underwater. The device was made up of a nose clip and a mouthpiece attached to an air tank that the rescue worker carried on his back. In 1871, British physicist John Tyndall invented a firemans respirator that filtered air against smoke and gas. In 1874, British inventor  Samuel Barton patented a device that permitted respiration in places where the atmosphere is charged with noxious gasses, or vapors, smoke, or other impurities, according to U.S. patent #148868. Garrett Morgan American  Garrett Morgan patented the Morgan safety hood and smoke protector in 1914. Two years later, Morgan made national news when his gas mask was used to rescue 32 men trapped during an explosion in an underground tunnel 250 feet beneath Lake Erie. The publicity led to the sale of the safety hood to firehouses across the United States. Some historians cite the Morgan design as the basis for early U.S. army gas masks used during WWI. Early air filters include simple devices such as a soaked handkerchief held over the nose and mouth. Those devices evolved into various hoods worn over the head and soaked with protective chemicals. Goggles for the eyes and later filters drums were added. Carbon Monoxide Respirator The British built a carbon monoxide respirator for use during WWI  in 1915, before the first use of chemical gas weapons. It was then discovered that unexploded enemy shells gave off high enough levels of carbon monoxide to kill soldiers in the trenches, foxholes and other contained environments. This is similar to the dangers of the exhaust from a car with its engine turned on in an enclosed garage. Cluny Macpherson Canadian  Cluny Macpherson designed a fabric smoke helmet with a single exhaling tube that came with chemical sorbents to defeat the airborne chlorine used in the gas attacks. Macphersons designs were used and modified by allied forces and are considered the first to be used to protect against chemical weapons. British Small Box Respirator In 1916, the Germans added larger air filter drums containing gas neutralizing chemicals to their respirators. The allies soon added filter drums to their respirators as well. One of the most notable gas masks used during WWI was the British Small Box Respirator or SBR designed in 1916. The SBR was probably the most reliable and heavily used gas masks used during WWI.

Guide to the Upper Paleolithic

Guide to the Upper Paleolithic The Upper Paleolithic (ca 40,000-10,000 years BP) was a period of great transition in the world. The Neanderthals in Europe became edged out and disappeared by 33,000 years ago, and modern humans began to have the world to themselves. While the notion of a creative explosion has given way to a recognition of a long history of the development of human behaviors long before we humans left Africa, there is no doubt that things really got cooking during the UP. Timeline of the Upper Paleolithic In Europe, it is traditional to split the Upper Paleolithic into five overlapping and somewhat regional variants, based on differences between stone and bone tool assemblages. Chatelperronian (~40,000-34,000 BP) Aurignacian (~45,000-29,000 BP) Gravettian/Upper Perigordian (29,000-22,000)Solutrean (22,000-18,000 BP)Magdalenian (17,000-11,000 BP) Azilian/Federmesser (13,000-11,000 BP) Tools of the Upper Paleolithic Stone tools of the Upper Paleolithic were primarily blade-based technology. Blades are stone pieces that are twice as long as they are wide  and, generally, have parallel sides. They were used to create an astonishing range of formal tools, tools created to specific, wide-spread patterns with specific purposes. In addition, bone, antler, shell and wood were used to a great degree for both artistic and working tool types, including the first eyed needles presumably for making clothing about 21,000 years ago. The UP is perhaps best known for the cave art, wall paintings and engravings of animals and abstractions at caves such as Altamira, Lascaux, and Coa. Another development during the UP is mobiliary art (basically, mobiliary art is that which can be carried), including the famous Venus figurines and sculpted batons of antler and bone carved with representations of animals. Upper Paleolithic Lifestyles People living during the Upper Paleolithic lived in houses, some built of mammoth bone, but most huts with semi-subterranean (dugout) floors, hearths, and windbreaks. Hunting became specialized, and sophisticated planning is shown by the culling of animals, selective choices by season, and selective butchery: the first hunter-gatherer economy. Occasional mass animal killings suggest that in some places and at some times, food storage was practiced. Some evidence (different site types and the so-called schlep effect) suggest that small groups of people went on hunting trips and returned with meat to the base camps. The first domesticated animal appears during the Upper Paleolithic: the dog, companion to us humans for over 15,000 years. Colonization during the UP Humans colonized Australia and the Americas by the end of the Upper Paleolithic  and moved into hitherto unexploited regions such as deserts and tundras. The End of the Upper Paleolithic The end of the UP came about because of climate change: global warming, which affected humanitys ability to fend for itself. Archaeologists have called that period of adjustment the Azilian. Upper Paleolithic Sites See Upper Paleolithic Sites in Europe Israel: Qafzeh Cave, Ohalo II Egypt: Nazlet Khater Morocco: Grotte des Pigeons Australia: Lake Mungo, Devils Lair, Willandra Lakes Japan: Sunagawa Georgia: Dzudzuana Cave China: Yuchanyan Cave Americas Daisy Cave, Monte Verde Sources See specific sites and issues for additional references. Cunliffe, Barry. 1998. Prehistoric Europe: An Illustrated History. Oxford University Press, Oxford. Fagan, Brian (editor). 1996 The Oxford Companion to Archaeology, Brian Fagan. Oxford University Press, Oxford.

Economics Paper Essay Example | Topics and Well Written Essays - 750 words

Economics Paper - Essay Example The product or service a firm offers is usually the only one present in the market, therefore, the distinction between a firm and an industry becomes blurred. The firm becomes synonymous to its product/service and to the industry. Monopolistic market deviates from a perfect competition market. A perfect competition market is characterized by infinite number of competing firms, many product/service offerings, and perfectly elastic demand, to name a few. Monopolistic market, on the other hand, has a single firm, limited number of product/service, and a relatively inelastic demand. The differences between the two are greatly felt from the point of view of the consumer in a monopolistic market who has a limited choice of product/service, supply, and unregulated price. Since the product/service offered by a firm in a monopolistic market is usually the only available choice, product/service substitutes are usually absent. It is difficult to find a product/service that closely resembles the one offered by a firm in a monopolistic market. Consumers are left with a choice of either buying the product the firm offers, buy a poor substitute (if a competition is present), or not buy at all (which is unlikely since the product/service offered in a monopolistic market is usually a basic need or commodity). A firm in a monopolistic market determines the price since it is the only supplier present. As opposed to a perfect competition environment where buyers/consumers dictate the price, a firm in a monopolistic market has the solitary control of price (i.e. price maker). Where there are more players in the market, more choices are offered to consumers; hence, the power to control the price is left at the hands of consumers. In a monopolistic market, the power lies in the hands of a single firm. Monopolistic competitive market is occupied by many competing firms while