Fumarole
A fumarole is an opening in a planet's crust which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrogen chloride, hydrogen sulfide. The steam forms when superheated water condenses as its pressure drops when it emerges from the ground; the name solfatara is given to fumaroles. Fumaroles may occur along long fissure, or in chaotic clusters or fields, they occur on the surface of lava or pyroclastic flows. A fumarole field is an area of thermal springs and gas vents where shallow magma or hot igneous rocks release gases or interact with groundwater; when they occur in freezing environments, fumaroles may cause fumarolic ice towers. Fumaroles may persist for centuries if located above a persistent heat source; the Valley of Ten Thousand Smokes, for example, was formed during the 1912 eruption of Novarupta in Alaska. Thousands of fumaroles occurred in the cooling ash from the eruption, but over time most of them have become extinct. An estimated four thousand fumaroles exist within the boundaries of Yellowstone National Park in the United States.
In April 2006 fumarole emissions killed three ski-patrol workers east of Chair 3 at Mammoth Mountain Ski Area in California. The workers were overpowered by toxic fumes. Another example is an array of fumaroles in the Valley of Desolation in Morne Trois Pitons National Park in Dominica. Fumaroles emitting sulfurous vapors form surface deposits of sulfur-rich minerals. Boiling Lake Cold seep Hydrothermal vent Mazuku Mofetta Mudpot Mud volcano Sulfur Mining on Gunung Welirang Volcano Chisholm, Hugh, ed.. "Fumarole". Encyclopædia Britannica. 11. Cambridge University Press. Pp. 300–301
Sulfuric acid
Sulfuric acid known as vitriol, is a mineral acid composed of the elements sulfur and hydrogen, with molecular formula H2SO4. It is a colorless and syrupy liquid, soluble in water, in a reaction, exothermic, its corrosiveness can be ascribed to its strong acidic nature, and, if at a high concentration, its dehydrating and oxidizing properties. It is hygroscopic absorbing water vapor from the air. Upon contact, sulfuric acid can cause severe chemical burns and secondary thermal burns. Sulfuric acid is a important commodity chemical, a nation's sulfuric acid production is a good indicator of its industrial strength, it is produced with different methods, such as contact process, wet sulfuric acid process, lead chamber process and some other methods. Sulfuric acid is a key substance in the chemical industry, it is most used in fertilizer manufacture, but is important in mineral processing, oil refining, wastewater processing, chemical synthesis. It has a wide range of end applications including in domestic acidic drain cleaners, as an electrolyte in lead-acid batteries, in various cleaning agents.
Although nearly 100% sulfuric acid can be made, the subsequent loss of SO3 at the boiling point brings the concentration to 98.3% acid. The 98.3% grade is more stable in storage, is the usual form of what is described as "concentrated sulfuric acid". Other concentrations are used for different purposes; some common concentrations are: "Chamber acid" and "tower acid" were the two concentrations of sulfuric acid produced by the lead chamber process, chamber acid being the acid produced in the lead chamber itself and tower acid being the acid recovered from the bottom of the Glover tower. They are now obsolete as commercial concentrations of sulfuric acid, although they may be prepared in the laboratory from concentrated sulfuric acid if needed. In particular, "10M" sulfuric acid is prepared by adding 98% sulfuric acid to an equal volume of water, with good stirring: the temperature of the mixture can rise to 80 °C or higher. Sulfuric acid reacts with its anhydride, SO3, to form H2S2O7, called pyrosulfuric acid, fuming sulfuric acid, Disulfuric acid or oleum or, less Nordhausen acid.
Concentrations of oleum are either expressed in terms of % SO3 or as % H2SO4. Pure H2S2O7 is a solid with melting point of 36 °C. Pure sulfuric acid has a vapor pressure of <0.001 mmHg at 25 °C and 1 mmHg at 145.8 °C, 98% sulfuric acid has a <1 mmHg vapor pressure at 40 °C. Pure sulfuric acid is a viscous clear liquid, like oil, this explains the old name of the acid. Commercial sulfuric acid is sold in several different purity grades. Technical grade H2SO4 is impure and colored, but is suitable for making fertilizer. Pure grades, such as United States Pharmacopeia grade, are used for making pharmaceuticals and dyestuffs. Analytical grades are available. Nine hydrates are known, but four of them were confirmed to be tetrahydrate and octahydrate. Anhydrous H2SO4 is a polar liquid, having a dielectric constant of around 100, it has a high electrical conductivity, caused by dissociation through protonating itself, a process known as autoprotolysis. 2 H2SO4 ⇌ H3SO+4 + HSO−4The equilibrium constant for the autoprotolysis is Kap = = 2.7×10−4The comparable equilibrium constant for water, Kw is 10−14, a factor of 1010 smaller.
In spite of the viscosity of the acid, the effective conductivities of the H3SO+4 and HSO−4 ions are high due to an intramolecular proton-switch mechanism, making sulfuric acid a good conductor of electricity. It is an excellent solvent for many reactions; because the hydration reaction of sulfuric acid is exothermic, dilution should always be performed by adding the acid to the water rather than the water to the acid. Because the reaction is in an equilibrium that favors the rapid protonation of water, addition of acid to the water ensures that the acid is the limiting reagent; this reaction is best thought of as the formation of hydronium ions: H2SO4 + H2O → H3O+ + HSO−4 Ka1 = 2.4×106 HSO−4 + H2O → H3O+ + SO2−4 Ka2 = 1.0×10−2 HSO−4 is the bisulfate anion and SO2−4 is the sulfate anion. Ka1 and Ka2 are the acid dissociation constants; because the hydration of sulfuric acid is thermodynamically favorable and the affinity of it for water is sufficiently strong, sulfuric acid is an excellent dehydrating agent.
Concentrated sulfuric acid has a powerful dehydrating property, removing water from other chemical compounds including sugar and other carbohydrates and producing carbon and steam. In the laboratory, this is demonstrated by mixing table sugar into sulfuric acid; the sugar changes from white to dark brown and to black as carbon is formed. A rigid column of black, porous carbon will emerge as well; the carbon will smell of caramel due to the heat generated. C 12 H 22 O 11 ⏞ sucrose → H 2 SO 4 12 C + 11 H 2
Archaea
Archaea constitute a domain of single-celled microorganisms. These microbes are prokaryotes. Archaea were classified as bacteria, receiving the name archaebacteria, but this classification is outdated. Archaeal cells have unique properties separating them from the other two domains of life and Eukarya. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in the laboratory and were only detected by analysis of their nucleic acids in samples from their environment. Archaea and bacteria are similar in size and shape, although a few archaea have shapes quite unlike that of bacteria, such as the flat and square-shaped cells of Haloquadratum walsbyi. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more related to those of eukaryotes, notably for the enzymes involved in transcription and translation. Other aspects of archaeal biochemistry are unique, such as their reliance on ether lipids in their cell membranes, including archaeols.
Archaea use more energy sources than eukaryotes: these range from organic compounds, such as sugars, to ammonia, metal ions or hydrogen gas. Salt-tolerant archaea use sunlight as an energy source, other species of archaea fix carbon, but unlike plants and cyanobacteria, no known species of archaea does both. Archaea reproduce asexually by budding; the first observed archaea were extremophiles, living in harsh environments, such as hot springs and salt lakes with no other organisms, but improved detection tools led to the discovery of archaea in every habitat, including soil and marshlands. They are part of the microbiota of all organisms, in the human microbiota they are important in the gut, on the skin. Archaea are numerous in the oceans, the archaea in plankton may be one of the most abundant groups of organisms on the planet. Archaea are a major part of Earth's life, may play roles in the carbon cycle and the nitrogen cycle. No clear examples of archaeal pathogens or parasites are known. Instead they are mutualists or commensals, such as the methanogens that inhabit the gastrointestinal tract in humans and ruminants, where their vast numbers aid digestion.
Methanogens are used in biogas production and sewage treatment, biotechnology exploits enzymes from extremophile archaea that can endure high temperatures and organic solvents. For much of the 20th century, prokaryotes were regarded as a single group of organisms and classified based on their biochemistry and metabolism. For example, microbiologists tried to classify microorganisms based on the structures of their cell walls, their shapes, the substances they consume. In 1965, Emile Zuckerkandl and Linus Pauling proposed instead using the sequences of the genes in different prokaryotes to work out how they are related to each other; this phylogenetic approach is the main method used today. Archaea – at that time only the methanogens were known – were first classified separately from bacteria in 1977 by Carl Woese and George E. Fox based on their ribosomal RNA genes, they called these groups the Urkingdoms of Archaebacteria and Eubacteria, though other researchers treated them as kingdoms or subkingdoms.
Woese and Fox gave the first evidence for Archaebacteria as a separate "line of descent": 1. Lack of peptidoglycan in their cell walls, 2. Two unusual coenzymes, 3. Results of 16S ribosomal RNA gene sequencing. To emphasize this difference, Otto Kandler and Mark Wheelis proposed reclassifying organisms into three natural domains known as the three-domain system: the Eukarya, the Bacteria and the Archaea, in what is now known as "The Woesian Revolution"; the word archaea comes from the Ancient Greek ἀρχαῖα, meaning "ancient things", as the first representatives of the domain Archaea were methanogens and it was assumed that their metabolism reflected Earth's primitive atmosphere and the organisms' antiquity, but as new habitats were studied, more organisms were discovered. Extreme halophilic and hyperthermophilic microbes were included in Archaea. For a long time, archaea were seen as extremophiles that only exist in extreme habitats such as hot springs and salt lakes, but by the end of the 20th century, archaea had been identified in non-extreme environments as well.
Today, they are known to be a large and diverse group of organisms abundantly distributed throughout nature. This new appreciation of the importance and ubiquity of archaea came from using polymerase chain reaction to detect prokaryotes from environmental samples by multiplying their ribosomal genes; this allows the detection and identification of organisms that have not been cultured in the laboratory. The classification of archaea, of prokaryotes in general, is a moving and contentious field. Current classification systems aim to organize archaea into groups of organisms that share structural features and common ancestors; these classifications rely on the use of the sequence of ribosomal RNA genes to reveal relationships between organisms. Most of the culturable and well-investigated species of archaea are members of two main phyla, the Euryarchaeota and Crenarchaeota. Other groups have been tentatively created. For example, the peculiar species Nanoarchaeum equitans, discovered in 2003, has been given its own phylum, the Nanoarchaeota.
A new phylum Korarchaeota has been proposed. It contains a sm
Polymerase chain reaction
Polymerase chain reaction is a method used in molecular biology to make many copies of a specific DNA segment. Using PCR, a single copy of a DNA sequence is exponentially amplified to generate thousands to millions of more copies of that particular DNA segment. PCR is now a common and indispensable technique used in medical laboratory and clinical laboratory research for a broad variety of applications including biomedical research and criminal forensics. PCR was developed by Kary Mullis in 1983, he was awarded the Nobel Prize in Chemistry in 1993 for his work in developing the method. The vast majority of PCR methods rely on thermal cycling. Thermal cycling exposes reactants to repeated cycles of heating and cooling to permit different temperature-dependent reactions—specifically, DNA melting and enzyme-driven DNA replication. PCR employs two main reagents - a DNA polymerase. In the first step of PCR, the two strands of the DNA double helix are physically separated at a high temperature in a process called DNA melting.
In the second step, the temperature is lowered and the primers bind to the complementary sequences of DNA. The two DNA strands become templates for DNA polymerase to enzymatically assemble a new DNA strand from free nucleotides, the building blocks of DNA; as PCR progresses, the DNA generated is itself used as a template for replication, setting in motion a chain reaction in which the original DNA template is exponentially amplified. All PCR applications employ a heat-stable DNA polymerase, such as Taq polymerase, an enzyme isolated from the thermophilic bacterium Thermus aquaticus. If the polymerase used was heat-susceptible, it would denature under the high temperatures of the denaturation step. Before the use of Taq polymerase, DNA polymerase had to be manually added every cycle, a tedious and costly process. Applications of the technique include DNA cloning for sequencing, gene cloning and manipulation, gene mutagenesis. PCR amplifies a specific region of a DNA strand. Most PCR methods amplify DNA fragments of between 0.1 and 10 kilo base pairs in length, although some techniques allow for amplification of fragments up to 40 kbp.
The amount of amplified product is determined by the available substrates in the reaction, which become limiting as the reaction progresses. A basic PCR set-up requires several components and reagents, including a DNA template that contains the DNA target region to amplify; the thermal cycler heats and cools the reaction tubes to achieve the temperatures required at each step of the reaction. Many modern thermal cyclers make use of the Peltier effect, which permits both heating and cooling of the block holding the PCR tubes by reversing the electric current. Thin-walled reaction tubes permit favorable thermal conductivity to allow for rapid thermal equilibration. Most thermal cyclers have heated lids to prevent condensation at the top of the reaction tube. Older thermal cyclers lacking a heated lid require a layer of oil on top of the reaction mixture or a ball of wax inside the tube. PCR consists of a series of 20–40 repeated temperature changes, called thermal cycles, with each cycle consisting of two or three discrete temperature steps.
The cycling is preceded by a single temperature step at a high temperature, followed by one hold at the end for final product extension or brief storage. The temperatures used and the length of time they are applied in each cycle depend on a variety of parameters, including the enzyme used for DNA synthesis, the concentration of bivalent ions and dNTPs in the reaction, the melting temperature of the primers; the individual steps common to most PCR methods are as follows: Initialization: This step is only required for DNA polymerases that require heat acti
Deep sea
The deep sea or deep layer is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms or more. Little or no light penetrates this part of the ocean, most of the organisms that live there rely for subsistence on falling organic matter produced in the photic zone. For this reason, scientists once assumed that life would be sparse in the deep ocean, but every probe has revealed that, on the contrary, life is abundant in the deep ocean. From the time of Pliny until the late nineteenth century...humans believed there was no life in the deep. It took a historic expedition in the ship Challenger between 1876 to prove Pliny wrong, yet in the twentieth century scientists continued to imagine that life at great depth was insubstantial, or somehow inconsequential. The eternal dark, the inconceivable pressure, the extreme cold that exist below one thousand meters were, they thought, so forbidding as to have all but extinguished life; the reverse is in fact true....
Lies the largest habitat on earth. In 1960, the Bathyscaphe Trieste descended to the bottom of the Mariana Trench near Guam, at 10,911 m, the deepest known spot in any ocean. If Mount Everest were submerged there, its peak would be more than a mile beneath the surface; the Trieste was retired, for a while the Japanese remote-operated vehicle Kaikō was the only vessel capable of reaching this depth. It was lost at sea in 2003. In May and June 2009, the hybrid-ROV Nereus returned to the Challenger Deep for a series of three dives to depths exceeding 10,900 meters, it has been suggested. Little was known about the extent of life on the deep ocean floor until the discovery of thriving colonies of shrimps and other organisms around hydrothermal vents in the late 1970s. Before the discovery of the undersea vents, it had been accepted that all life on earth obtained its energy from the sun; the new discoveries revealed groups of creatures that obtained nutrients and energy directly from thermal sources and chemical reactions associated with changes to mineral deposits.
These organisms thrive in lightless and anaerobic environments in saline water that may reach 300 °F, drawing their sustenance from hydrogen sulfide, toxic to all terrestrial life. The revolutionary discovery that life can exist under these extreme conditions changed opinions about the chances of there being life elsewhere in the universe. Scientists now speculate that Europa, one of Jupiter's moons, may be able to support life beneath its icy surface, where there is evidence of a global ocean of liquid water. Natural light does not penetrate the deep ocean, with the exception of the upper parts of the mesopelagic. Since photosynthesis is not possible, plants cannot live in this zone. Since plants are the primary producers of all of earth's ecosystems, life in this area of the ocean must depend on energy sources from elsewhere. Except for the areas close to the hydrothermal vents, this energy comes from organic material drifting down from the photic zone; the sinking organic material is composed of algal particulates and other forms of biological waste, collectively referred to as marine snow.
Because pressure in the ocean increases by about 1 atmosphere for every 10 meters of depth, the amount of pressure experienced by many marine organisms is extreme. Until recent years, the scientific community lacked detailed information about the effects of pressure on most deep sea organisms because the specimens encountered arrived at the surface dead or dying and weren't observable at the pressures at which they lived. With the advent of traps that incorporate a special pressure-maintaining chamber, undamaged larger metazoan animals have been retrieved from the deep sea in good condition. Salinity is remarkably constant throughout the deep sea, at about 35 parts per thousand. There are some minor differences in salinity, but none that are ecologically significant, except in the Mediterranean and Red Seas; the two areas of greatest and most rapid temperature change in the oceans are the transition zone between the surface waters and the deep waters, the thermocline, the transition between the deep-sea floor and the hot water flows at the hydrothermal vents.
Thermoclines vary in thickness from a few hundred meters to nearly a thousand meters. Below the thermocline, the water mass of the deep ocean is far more homogeneous. Thermoclines are strongest in the tropics, where the temperature of the epipelagic zone is above 20 °C. From the base of the epipelagic, the temperature drops over several hundred meters to 5 or 6 °C at 1,000 meters, it continues to decrease to the bottom. Below 3,000 to 4,000 m, the water is isothermal between 0 and 3 °C; the cold water stems from sinking heavy surface water in the polar regions. At any given depth, the temperature is unvarying over long periods of time. There are there any annual changes. No other habitat on earth has such a constant temperature. Hydrothermal vents are the direct contrast with constant temperature. In these systems, the temperature of the water as it emerges from the "black smoker" chimneys may be as high as 400 °C while within a few meters it may be back down to 2 - 4 °C. Regions below the epipelagic are divided into further zones, beginning with the mesopelagic which spans from 200 to 1000 meters below sea level, where so little light pen
PH
In chemistry, pH is a scale used to specify how acidic or basic a water-based solution is. Acidic solutions have a lower pH, while basic solutions have a higher pH. At room temperature, pure water is neither acidic nor basic and has a pH of 7; the pH scale is logarithmic and approximates the negative of the base 10 logarithm of the molar concentration of hydrogen ions in a solution. More it is the negative of the base 10 logarithm of the activity of the hydrogen ion. At 25 °C, solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic; the neutral value of the pH depends on the temperature, being lower than 7 if the temperature increases. Contrary to popular belief, the pH value can be less than 0 or greater than 14 for strong acids and bases respectively; the pH scale is traceable to a set of standard solutions whose pH is established by international agreement. Primary pH standard values are determined using a concentration cell with transference, by measuring the potential difference between a hydrogen electrode and a standard electrode such as the silver chloride electrode.
The pH of aqueous solutions can be measured with a glass electrode and a pH meter, or a color-changing indicator. Measurements of pH are important in chemistry, medicine, water treatment, many other applications; the concept of pH was first introduced by the Danish chemist Søren Peder Lauritz Sørensen at the Carlsberg Laboratory in 1909 and revised to the modern pH in 1924 to accommodate definitions and measurements in terms of electrochemical cells. In the first papers, the notation had the "H" as a subscript to the lowercase "p", as so: pH; the exact meaning of the "p" in "pH" is disputed, but according to the Carlsberg Foundation, pH stands for "power of hydrogen". It has been suggested that the "p" stands for the German Potenz, others refer to French puissance. Another suggestion is that the "p" stands for the Latin terms pondus hydrogenii, potentia hydrogenii, or potential hydrogen, it is suggested that Sørensen used the letters "p" and "q" to label the test solution and the reference solution.
In chemistry, the p stands for "decimal cologarithm of", is used in the term pKa, used for acid dissociation constants. Bacteriologist Alice C. Evans, famed for her work's influence on dairying and food safety, credited William Mansfield Clark and colleagues with developing pH measuring methods in the 1910s, which had a wide influence on laboratory and industrial use thereafter. In her memoir, she does not mention how much, or how little and colleagues knew about Sørensen's work a few years prior, she said: In these studies Dr. Clark's attention was directed to the effect of acid on the growth of bacteria, he found that it is the intensity of the acid in terms of hydrogen-ion concentration that affects their growth. But existing methods of measuring acidity determined not the intensity, of the acid. Next, with his collaborators, Dr. Clark developed accurate methods for measuring hydrogen-ion concentration; these methods replaced the inaccurate titration method of determining acid content in use in biologic laboratories throughout the world.
They were found to be applicable in many industrial and other processes in which they came into wide usage. The first electronic method for measuring pH was invented by Arnold Orville Beckman, a professor at California Institute of Technology in 1934, it was in response to local citrus grower Sunkist that wanted a better method for testing the pH of lemons they were picking from their nearby orchards. PH is defined as the decimal logarithm of the reciprocal of the hydrogen ion activity, aH+, in a solution. PH = − log 10 = log 10 For example, for a solution with a hydrogen ion activity of 5×10−6 we get 1/ = 2×105, thus such a solution has a pH of log10 = 5.3. For a commonplace example based on the facts that the masses of a mole of water, a mole of hydrogen ions, a mole of hydroxide ions are 18 g, 1 g, 17 g, a quantity of 107 moles of pure water, or 180 tonnes, contains close to 1 g of dissociated hydrogen ions and 17 g of hydroxide ions. Note that pH depends on temperature. For instance at 0 °C the pH of pure water is 7.47.
At 25 °C it's 7.00, at 100 °C it's 6.14. This definition was adopted because ion-selective electrodes, which are used to measure pH, respond to activity. Ideally, electrode potential, E, follows the Nernst equation, for the hydrogen ion can be written as E = E 0 + R T F ln = E 0 − 2.303 R T F pH where E is a measured potential, E0 is the standard electrode potential, R is the gas const
Yellowstone National Park
Yellowstone National Park is an American national park located in Wyoming and Idaho. It was established by the U. S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872. Yellowstone was the first national park in the U. S. and is widely held to be the first national park in the world. The park is known for its wildlife and its many geothermal features Old Faithful geyser, one of its most popular features, it has many types of ecosystems. It is part of the South Central Rockies forests ecoregion. Native Americans have lived in the Yellowstone region for at least 11,000 years. Aside from visits by mountain men during the early-to-mid-19th century, organized exploration did not begin until the late 1860s. Management and control of the park fell under the jurisdiction of the Secretary of the Interior, the first being Columbus Delano. However, the U. S. Army was subsequently commissioned to oversee management of Yellowstone for a 30-year period between 1886 and 1916. In 1917, administration of the park was transferred to the National Park Service, created the previous year.
Hundreds of structures have been built and are protected for their architectural and historical significance, researchers have examined more than a thousand archaeological sites. Yellowstone National Park spans an area of 3,468.4 square miles, comprising lakes, canyons and mountain ranges. Yellowstone Lake is one of the largest high-elevation lakes in North America and is centered over the Yellowstone Caldera, the largest supervolcano on the continent; the caldera is considered an active volcano. It has erupted with tremendous force several times in the last two million years. Half of the world's geysers and hydrothermal features are in Yellowstone, fueled by this ongoing volcanism. Lava flows and rocks from volcanic eruptions cover most of the land area of Yellowstone; the park is the centerpiece of the Greater Yellowstone Ecosystem, the largest remaining nearly-intact ecosystem in the Earth's northern temperate zone. In 1978, Yellowstone was named a UNESCO World Heritage Site. Hundreds of species of mammals, birds and reptiles have been documented, including several that are either endangered or threatened.
The vast forests and grasslands include unique species of plants. Yellowstone Park is the largest and most famous megafauna location in the contiguous United States. Grizzly bears and free-ranging herds of bison and elk live in this park; the Yellowstone Park bison herd is the largest public bison herd in the United States. Forest fires occur in the park each year. Yellowstone has numerous recreational opportunities, including hiking, boating and sightseeing. Paved roads provide close access to the major geothermal areas as well as some of the lakes and waterfalls. During the winter, visitors access the park by way of guided tours that use either snow coaches or snowmobiles; the park contains the headwaters of the Yellowstone River. Near the end of the 18th century, French trappers named the river Roche Jaune, a translation of the Hidatsa name Mi tsi a-da-zi. American trappers rendered the French name in English as "Yellow Stone". Although it is believed that the river was named for the yellow rocks seen in the Grand Canyon of the Yellowstone, the Native American name source is unclear.
The human history of the park begins at least 11,000 years ago when Native Americans began to hunt and fish in the region. During the construction of the post office in Gardiner, Montana, in the 1950s, an obsidian projectile point of Clovis origin was found that dated from 11,000 years ago; these Paleo-Indians, of the Clovis culture, used the significant amounts of obsidian found in the park to make cutting tools and weapons. Arrowheads made of Yellowstone obsidian have been found as far away as the Mississippi Valley, indicating that a regular obsidian trade existed between local tribes and tribes farther east. By the time white explorers first entered the region during the Lewis and Clark Expedition in 1805, they encountered the Nez Perce and Shoshone tribes. While passing through present day Montana, the expedition members heard of the Yellowstone region to the south, but they did not investigate it. In 1806, John Colter, a member of the Lewis and Clark Expedition, left to join a group of fur trappers.
After splitting up with the other trappers in 1807, Colter passed through a portion of what became the park, during the winter of 1807–1808. He observed at least one geothermal area near Tower Fall. After surviving wounds he suffered in a battle with members of the Crow and Blackfoot tribes in 1809, Colter described a place of "fire and brimstone" that most people dismissed as delirium. Over the next 40 years, numerous reports from mountain men and trappers told of boiling mud, steaming rivers, petrified trees, yet most of these reports were believed at the time to be myth. After an 1856 exploration, mountain man Jim Bridger reported observing boiling springs, spouting water, a mountain of glass and yellow rock; these reports were ignored because Bridger was a known "spinner of yarns". In 1859, a U. S. Army Surveyor named Captain William F. Raynolds embarked on a two-year survey of the northern Rockies. After wintering in Wyoming, in May 1860, Raynolds and his party – which included naturalist Ferdinand Vandeveer Hayden and guide Jim B
