Google Earth is a computer program that renders a 3D representation of Earth based on satellite imagery. The program maps the Earth by superimposing satellite images, aerial photography, GIS data onto a 3D globe, allowing users to see cities and landscapes from various angles. Users can explore the globe by using a keyboard or mouse; the program can be downloaded on a smartphone or tablet, using a touch screen or stylus to navigate. Users may use the program to add their own data using Keyhole Markup Language and upload them through various sources, such as forums or blogs. Google Earth is able to show various kinds of images overlaid on the surface of the earth and is a Web Map Service client. In addition to Earth navigation, Google Earth provides a series of other tools through the desktop application. Additional globes for the Moon and Mars are available, as well as a tool for viewing the night sky. A flight simulator game is included. Other features allow users to view photos from various places uploaded to Panoramio, information provided by Wikipedia on some locations, Street View imagery.
The web-based version of Google Earth includes Voyager, a feature that periodically adds in-program tours presented by scientists and documentarians. Google Earth has been viewed by some as a threat to privacy and national security, leading to the program being banned in multiple countries; some countries have requested that certain areas be obscured in Google's satellite images areas containing military facilities. The core technology behind Google Earth was developed at Intrinsic Graphics in the late 1990s. At the time, the company was developing 3D gaming software libraries; as a demo of their 3D software, they created a spinning globe that could be zoomed into, similar to the Powers of Ten film. The demo was popular, but the board of Intrinsic wanted to remain focused on gaming, so in 1999, they created Keyhole, Inc. headed by John Hanke. Keyhole developed a way to stream large databases of mapping data over the internet to client software, a key part of the technology, acquired patchworks of mapping data from governments and other sources.
The product, called "Keyhole EarthViewer", was sold on CDs for use in fields such as real estate, urban planning and intelligence. Despite making a number of capital deals with Nvidia and Sony, the small company was struggling to make payroll, employees were leaving. Fortunes for the company changed in early 2003 when CNN received a discount for the software in exchange for placing the Keyhole logo on-air whenever the map was used. Keyhole did not expect it would amount to more than brief 5 or 10 second prerecorded animation clips, but it was used extensively by Miles O'Brien live during the 2003 invasion of Iraq, allowing CNN and millions of viewers to follow the progress of the war in a way that had never been seen before. Public interest in the software exploded and Keyhole servers were not able to keep up with demand. Keyhole was soon contacted by the Central Intelligence Agency's venture capital firm, In-Q-Tel, the National Geospatial-Intelligence Agency, for use with defense mapping databases, which gave Keyhole a much-needed cash infusion.
Intrinsic Graphics was sold in 2003 to Vicarious Visions after its gaming libraries did not sell well, its core group of engineers and management transitioned to Keyhole with Hanke remaining at the head. At the time, Google was finding that over 25% of its searches were of a geospatial character, including searches for maps and directions. In October 2004, Google acquired Keyhole as part of a strategy to better serve its users. Google Earth's imagery is displayed on a digital globe, which displays the planet's surface using a single composited image from a far distance. After zooming in far enough, the imagery transitions into different imagery of the same area with finer detail, which varies in date and time from one area to the next; the imagery is retrieved from satellites or aircraft. Before the launch of NASA and the USGS's Landsat 8 satellite, Google relied on imagery from Landsat 7, which suffered from a hardware malfunction that left diagonal gaps in images. In 2013, Google used datamining to remedy the issue, providing what was described as a successor to the Blue Marble image of Earth, with a single large image of the entire planet.
This was achieved by combining multiple sets of imagery taken from Landsat 7 to eliminate clouds and diagonal gaps, creating a single "mosaic" image. Google now uses Landsat 8 to provide imagery with greater frequency. Imagery is hosted on Google's servers, which are contacted by the application when opened, requiring an Internet connection. Imagery resolution ranges from 15 meters of resolution to 15 centimeters. For much of the Earth, Google Earth uses digital elevation model data collected by NASA's Shuttle Radar Topography Mission; this creates the impression of three-dimensional terrain where the imagery is only two-dimensional. Every image created from Google Earth using satellite data provided by Google Earth is a copyrighted map. Any derivative from Google Earth is made from copyrighted data which, under United States Copyright Law, may not be used except under the licenses Google provides. Google allows non-commercial personal use of the images as long as copyrights and attributions are preserved.
By contrast, images created with NASA's globe software World Wind use The Blue Marble, Landsat, or USGS imagery, each of, in the public domain. In version 5.0, Google introduced Historical Imagery. Clicking the clock icon in the toolbar opens a time slider, which marks the tim
Maize known as corn, is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits. Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. However, little of this maize is consumed directly by humans: most is used for corn ethanol, animal feed and other maize products, such as corn starch and corn syrup; the six major types of maize are dent corn, flint corn, pod corn, flour corn, sweet corn. Maize is the most grown grain crop throughout the Americas, with 361 million metric tons grown in the United States in 2014. 40% of the crop—130 million tons—is used for corn ethanol. Genetically modified maize made up 85% of the maize planted in the United States in 2009. Sugar-rich varieties called sweet corn are grown for human consumption as kernels, while field corn varieties are used for animal feed, various corn-based human food uses, as chemical feedstocks.
Maize is used in making ethanol and other biofuels. Most historians believe. Recent research in the early 21st century has modified this view somewhat. An influential 2002 study by Matsuoka et al. has demonstrated that, rather than the multiple independent domestications model, all maize arose from a single domestication in southern Mexico about 9,000 years ago. The study demonstrated that the oldest surviving maize types are those of the Mexican highlands. Maize spread from this region over the Americas along two major paths; this is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands. Archaeologist Dolores Piperno has said: A large corpus of data indicates that it was dispersed into lower Central America by 7600 BP and had moved into the inter-Andean valleys of Colombia between 7000 and 6000 BP. Since even earlier dates have been published. According to a genetic study by Embrapa, corn cultivation was introduced in South America from Mexico, in two great waves: the first, more than 6000 years ago, spread through the Andes.
Evidence of cultivation in Peru has been found dating to about 6700 years ago. The second wave, about 2000 years ago, through the lowlands of South America. Before domestication, maize plants grew only small, 25 millimetres long corn cobs, only one per plant. In Spielvogel's view, many centuries of artificial selection by the indigenous people of the Americas resulted in the development of maize plants capable of growing several cobs per plant, which were several centimetres/inches long each; the Olmec and Maya cultivated maize in numerous varieties throughout Mesoamerica. It was believed. Research of the 21st century has established earlier dates; the region developed a trade network based on surplus and varieties of maize crops. Mapuches of south-central Chile cultivated maize along with quinoa and potatoes in Pre-Hispanic times, however potato was the staple food of most Mapuches, "specially in the southern and coastal territories where maize did not reach maturity". Before the expansion of the Inca Empire maize was traded and transported as far south as 40°19' S in Melinquina, Lácar Department.
In that location maize remains were found inside pottery dated to 730 ±80 BP and 920 ±60 BP. This maize was brought across the Andes from Chile; the presence of maize in Guaitecas Archipelago, which constitute southernmost outspost of Pre-Hispanic agriculture, is reported by early Spanish explorers. However the Spanish may have misidentified the plant. After the arrival of Europeans in 1492, Spanish settlers consumed maize and explorers and traders carried it back to Europe and introduced it to other countries. Spanish settlers far preferred wheat bread to cassava, or potatoes. Maize flour could not be substituted for wheat for communion bread, since in Christian belief only wheat could undergo transubstantiation and be transformed into the body of Christ; some Spaniards worried that by eating indigenous foods, which they did not consider nutritious, they would weaken and risk turning into Indians. "In the view of Europeans, it was the food they ate more than the environment in which they lived, that gave Amerindians and Spaniards both their distinctive physical characteristics and their characteristic personalities."
Despite these worries, Spaniards did consume maize. Archeological evidence from Florida sites indicate. Maize spread to the rest of the world because of its ability to grow in diverse climates, it was cultivated in Spain just a few decades after Columbus's voyages and spread to Italy, West Africa and elsewhere. The word maize derives from the Spanish form of the indigenous Taíno word for mahiz, it is known by other names around the world. The word "corn" outside North America and New Zealand refers to any cereal crop, its meaning understood to vary geographically to refer to the local staple. In the United Stat
James Hardin Younger was a notable American outlaw and member of the James–Younger Gang. He was the brother of Cole and Bob Younger Born in Missouri on January 15, 1848. Jim Younger was the ninth of fourteen children born to Henry Washington Younger and Bersheba Leighton Fristoe. With his brother Cole, he joined the Confederate Army during the American Civil War becoming a member of Quantrill's Raiders in 1864. Jim was captured by Union troops, in the same ambush that resulted in William Quantrill's death, was imprisoned until the war's end. After the war Jim tried his hand including starting a horse ranch. In 1873 he joined the James–Younger Gang, founded by Cole, along with Frank and Jesse James. It's uncertain how much time he spent with the gang, but he was present when his brother John was killed by Pinkertons in Roscoe, Missouri in 1874, he spent the next two years working a ranch in San Luis Obispo, California. Jim returned to the gang in time to join the ill-fated 1876 bank job in Minnesota.
Part of his jaw was shot off and he was captured and sentenced to life imprisonment. Along with Cole, he was paroled in 1901. After his release he became engaged to Alix Mueller, who had met him in prison 20 years after the Northfield robbery. Due to the terms of his parole, Jim couldn't marry, he committed suicide on October 19, 1902. His body was returned to Missouri for burial. In 1941, Younger was portrayed by actor Arthur Kennedy in the film Bad Men of Missouri. In 1950, Dewey Martin played Younger in the film Kansas Raiders, about his time spent with Quantrill's Raiders. In 1954, Sheb Wooley played Younger in an episode of Jim Davis's syndicated western television series, Stories of the Century. In the 1972 film The Great Northfield Minnesota Raid. In the 1980 film The Long Riders. In the TV show Dr. Quinn, Medicine Woman, he was portrayed in the episode "Baby Outlaws S3E21" by Donnie Jeffcoat In the 2001 film American Outlaws he was portrayed by Gregory Smith. James-Younger gang at civilwarstlouis.com Younger family genealogy on the official website for the family of Jesse James: Stray Leaves, A James Family in America Since 1650 Minnesota Historical Society History Topics: Northfield Raid and James-Younger Gang
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
Mankato is a city in Blue Earth, Le Sueur counties in the state of Minnesota. The population was 41,720 according to 2016 US census estimates, making it the fifth largest city in Minnesota outside the Minneapolis–Saint Paul metropolitan area; the county seat of Blue Earth County, it is located along a large bend of the Minnesota River at its confluence with the Blue Earth River. Mankato is across the Minnesota River from North Mankato. Mankato and North Mankato have a combined population of over 56,000 according to the 2017 census estimates, it encompasses the town of Skyline. North of Mankato Regional Airport, a tiny non-contiguous part of the city lies within Le Sueur County. Most of the city is in Blue Earth County. Mankato is the larger of the two principal cities of the Mankato-North Mankato metropolitan area, which covers Blue Earth and Nicollet counties and had a combined population of 94,149 at the 2010 census; the 2017 Census estimate is 100,939. Mankato was designated a Metropolitan Statistical Area by the US Census Bureau in November 2008.
Mankato was named the second best college town in the United States by Schools.com in 2017. The area was long settled by various cultures of indigenous peoples. After European colonization began on the East Coast, pressure from settlement and other Native American tribes caused various peoples to migrate into the area. By the mid-19th century, four Dakota language–speaking divisions of the Dakota Sioux were the primary indigenous group. Mankato Township was not settled by European Americans until Parsons King Johnson in February 1852, as part of the 19th-century migration of people from the east across the Midwest. New residents organized the city of Mankato on May 11, 1858; the city was organized by Henry Jackson, Parsons King Johnson, Col. D. A. Robertson, Justus C. Ramsey, others. A popular story says that the city was supposed to have been named Mahkato, but a typographical error by a clerk established the name as Mankato. According to Upham, quoting historian Thomas Hughes of Mankato, "The honor of christening the new city was accorded to Col. Robertson.
He had taken the name from Nicollet's book, in which the French explorer compared the'Mahkato" or Blue Earth River, with all its tributaries, to the water nymphs and their uncle in the German legend of Undine.'... No more appropriate name could be given the new city, than that of the noble river at whose mouth it is located." While it is uncertain that the city was intended to be called Mahkato, the Dakota called the river Makato Osa Watapa. The Anglo settlers adapted that as "Blue Earth River". According to Frederick Webb Hodge, in his "Handbook of American Indians North of Mexico," Volume 1, page 801, the town was named after the older of the two like-named chiefs of the Mdewakanton division of the Santee Dakota, whose village stood on or near the site of the present town. Ishtakhaba known as Chief Sleepy Eye, of the Sisseton band of Dakota Indians, was said to have directed settlers to this location, he said the site at the confluence of the Minnesota and Blue Earth Rivers was well suited to building and river traffic, yet safe from flooding.
On December 26, 1862, the US Army carried out the largest mass execution in U. S. history at Mankato following the Dakota War of 1862. Thirty-eight Dakota Native Americans were hanged for their parts in the uprising. A military tribunal had sentenced 303 to death, but President Lincoln reviewed the record and pardoned 265, believing they had been involved in legitimate defense against military forces. Episcopal Bishop Henry Benjamin Whipple had urged leniency in the case, but his position was not politically popular in Minnesota, nor was Lincoln's intervention. Two commemorative statues stand on the site of the hangings. In 1880, Mankato ranked fourth in size in the state; the population was 5,500. Former Vice President Schuyler Colfax died while traveling in Mankato on January 13, 1885. Mankato was the basis for Deep Valley in Maud Hart Lovelace's Betsy-Tacy series of children's books and novels; the children/young adult wing of the Blue Earth County Library is named in her honor. In Sinclair Lewis's 1920 novel Main Street, heroine Carol Milford is a former Mankato resident.
Lewis describes Mankato as follows: "In its garden-sheltered streets and aisles of elms is white and green New England reborn", alluding to its many migrants from New England, who brought their culture with them. Lewis wrote a substantial portion of the novel while staying at the J. W. Schmidt House at 315 South Broad Street, as now marked by a small plaque in front of the building. In the Little House on the Prairie television series, Mankato is a trading town that the citizens of Walnut Grove visit, it does not appear in the Laura Ingalls Wilder books. The 1972 film The New Land, a sequel to The Emigrants, both by Swedish director Jan Troell, depicts the mass execution of the 38 Dakota Indians at the end of the 1862 Dakota War. According to the United States Census Bureau, the city has a total area of 18.26 square miles, of which 17.91 square miles is land and 0.35 square miles is water. The Minnesota, Blue Earth, Le Sueur Rivers all flow through or near the city. Mankato has type Dfa. Winters are cold, with snow cover beginning between mid-November and mid-December, ending in March most years.
However, Mankato receives less snow than areas to its north and east. For example, Minneapolis, 75 miles northeast of Mankato, averages over 54 inches or 1.37 metres of snow per winter season, compared to Mankato's seasonal average of 35 inches or 0.89 metres. The coldest m
Garden City Township, Blue Earth County, Minnesota
Garden City Township is a township in Blue Earth County, United States. The population was 700 as of the 2000 census; the unincorporated community of Garden City is located within Garden City Township. The township is home to the Blue Earth County Fair. According to the United States Census Bureau, the township has a total area of 34.9 square miles, of which 33.1 square miles is land and 1.8 square miles is water. The southeast three-quarters of the city of Lake Crystal is within Garden City Township geographically but is a separate entity. Garden City U. S. Highway 169 Minnesota State Highway 60 Lake Crystal Loon Lake Mills Lake Judson Township South Bend Township Rapidan Township Lyra Township Vernon Center Township Ceresco Township Lincoln Township Butternut Valley Township The township includes Garden City Cemetery; as of the census of 2000, there were 700 people, 268 households, 209 families residing in the township. The population density was 21.2 people per square mile. There were 278 housing units at an average density of 8.4/sq mi.
The racial makeup of the township was 98.14% White, 0.29% Asian, 1.29% from other races, 0.29% from two or more races. Hispanic or Latino of any race were 1.71% of the population. There were 268 households out of which 33.2% had children under the age of 18 living with them, 69.4% are married couples living together, 3.4% had a female householder with no husband present, 22.0% were non-families. 16.8% of all households were made up of individuals and 9.3% had someone living alone, 65 years of age or older. The average household size is 2.61 and the average family size was 2.92. In the township the population was spread out with 24.3% under the age of 18, 6.6% from 18 to 24, 28.3% from 25 to 44, 27.1% from 45 to 64, 13.7% who are 65 years of age or older. The median age is 40 years. For every 100 females, there were 105.3 males. For every 100 females age 18 and over, there were 103.1 males. The median income for a household in the township was $51,750, the median income for a family was $54,896.
Males had a median income of $36,250 versus $26,094 for females. The per capita income for the township was $20,191. About 0.9% of families and 2.2% of the population were below the poverty line, including 2.1% of those under the age of 18 and 2.2% of those 65 and older. United States National Atlas United States Census Bureau 2007 TIGER/Line Shapefiles United States Board on Geographic Names
River engineering is the process of planned human intervention in the course, characteristics, or flow of a river with the intention of producing some defined benefit. People have intervened in the natural course and behaviour of rivers since before recorded history—to manage the water resources, to protect against flooding, or to make passage along or across rivers easier. From Roman times, rivers have been used as a source of hydropower. From the late 20th century, river engineering has had environmental concerns broader than immediate human benefit and some river engineering projects have been concerned with the restoration or protection of natural characteristics and habitats. Hydromodification encompasses the systematic response to alterations to riverine and non-riverine water bodies such as coastal waters and lakes; the U. S. Environmental Protection Agency has defined hydromodification as the "alteration of the hydrologic characteristics of coastal and non-coastal waters, which in turn could cause degradation of water resources."
River engineering has resulted in unintended systematic responses. The river engineering discipline now strives to repair hydromodified degradations and account for potential systematic response to planned alterations by considering fluvial geomorphology. Fluvial geomorphology is the study of. Fluvial geomorphology is the cumulation of a number of sciences including open channel hydraulics, sediment transport, physical geology, riparian ecology. River engineering attempts to understand fluvial geomorphology, implement a physical alteration, maintain public safety; the size of rivers above any tidal limit and their average freshwater discharge are proportionate to the extent of their basins and the amount of rain which, after falling over these basins, reaches the river channels in the bottom of the valleys, by which it is conveyed to the sea. The basin of a river is the expanse of country bounded by a watershed over which rainfall flows down towards the river traversing the lowest part of the valley, whereas the rain falling on the far slope of the watershed flows away to another river draining an adjacent basin.
River basins vary in extent according to the configuration of the country, ranging from the insignificant drainage areas of streams rising on high ground near the coast and flowing straight down into the sea, up to immense tracts of great continents, where rivers rising on the slopes of mountain ranges far inland have to traverse vast stretches of valleys and plains before reaching the ocean. The size of the largest river basin of any country depends on the extent of the continent in which it is situated, its position in relation to the hilly regions in which rivers arise and the sea into which they flow, the distance between the source and the outlet into the sea of the river draining it; the rate of flow of rivers depends upon their fall known as the gradient or slope. When two rivers of different sizes have the same fall, the larger river has the quicker flow, as its retardation by friction against its bed and banks is less in proportion to its volume than is the case with the smaller river.
The fall available in a section of a river corresponds to the slope of the country it traverses. Accordingly, in large basins, rivers in most cases begin as torrents with a variable flow, end as flowing rivers with a comparatively regular discharge; the irregular flow of rivers throughout their course forms one of the main difficulties in devising works for mitigating inundations or for increasing the navigable capabilities of rivers. In tropical countries subject to periodical rains, the rivers are in flood during the rainy season and have hardly any flow during the rest of the year, while in temperate regions, where the rainfall is more evenly distributed throughout the year, evaporation causes the available rainfall to be much less in hot summer weather than in the winter months, so that the rivers fall to their low stage in the summer and are liable to be in flood in the winter. In fact, with a temperate climate, the year may be divided into a warm and a cold season, extending from May to October and from November to April in the Northern hemisphere respectively.
The only exceptions are rivers which have their sources amongst mountains clad with perpetual snow and are fed by glaciers. But these rivers are liable to have their flow modified by the influx of tributaries subject to different conditions, so that the Rhone below Lyon has a more uniform discharge than most rivers, as the summer floods of the Arve are counteracted to a great extent by the low stage of the Saône flowing into the Rhone at Lyon, which has its floods in the winter when the Arve, on the contrary, is low. Another serious obstacle encountered in river engineering consists in the large quantity of detritus they bring down in flood-time, derived from the disintegration of the surface layers of the hills and slopes in the upper parts of the valleys by glaciers and rain; the power of a current to transport materia