The Civil War, from 1861 to 1865, is the centerpiece of our nation's story. It looms large, not merely because of its brutality and scope but because of its place in the course of American history. The seeds of war were planted long before 1861 and the conflict remains part of our national memory. Geography has helped shape this narrative. The physical landscape influenced economic differences between the regions, the desire to expand into new territories, the execution of the conflict both in the field and on the home front, and the ways in which our recollections have been shaped. Maps enable us to present the complex strands that, when woven together, provide a detailed account of the causes and conduct of the war. These visual images remain a salient aspect of our memory. Photographs, prints, diaries, songs and letters enhance our ability to tell this story, when our nation, as a Currier & Ives cartoon depicts, was about to be "Torn in Two." This exhibition tells the story of the American Civil War both nationally and locally in Boston, Massachusetts, through maps, documents, letters, and other primary sources. This exhibition was developed by the Norman B. Leventhal Map Center, a nonprofit organization established as a partnership between the Boston Public Library and philanthropist Norman Leventhal.

Western Mining History presents a short history of how a warehouse fire ignited a dynamite explosion that destroyed several blocks in Butte, Montana in 1895. Western Mining History is an historical site that provides databases, information on mining, mining towns, gold and Photos and maps of the western United States. Consider becoming a member or making a donation to help further the work of the site.

Western Mining History presents a brief summary of Colorado Mining Towns with links to additional Colorado resources for a mining town database and mines by county. Western Mining History is an historical site that provides information on mining, mining towns, gold and Photos and maps of the western United States. Consider becoming a member or making a donation to help further the work of the site.

Welcome to the White House 360 Virtual Tour! This immersive experience will bring you inside the halls of the White House and provide access to all the public rooms on the Ground and State Floors. It will also allow you to examine the rooms and objects even closer than you would in person.

This feature was made possible in part by the National Endowment for the Humanities: Exploring the human endeavor.

On April 26, 1913, Confederate Memorial Day, thirteen-year-old Mary Phagan was murdered at the National Pencil Company in Atlanta, Georgia. Leo Frank, the Jewish, New York-raised superintendent of the National Pencil Company, was charged with the crime. At the same time, Atlanta’s economy was transforming from rural and agrarian to urban and industrial. Resources for investing in new industry came from Northern states, as did most industrial leaders, like Leo Frank. Many of the workers in these new industrial facilities were children, like Mary Phagan. Over the next two years, Leo Frank’s legal case became a national story with a highly publicized, controversial trial and lengthy appeal process that profoundly affected Jewish communities in Georgia and the South, and impacted the careers of lawyers, politicians, and publishers. By the early twentieth century, Jewish communities had become well-established in most major Southern cities, continuing a path of migration that began during colonial times. The Leo Frank case and its aftermath revealed lingering regional hostilities from the Civil War and Reconstruction, intensified existing racial and cultural inequalities (particularly anti-Semitism), embodied socioeconomic problems (such as child labor), and exposed the brutality of lynching in the South. The exhibition was created by the Digital Library of Georgia (http://dlg.galileo.usg.edu/). Exhibition Organizers: Charles Pou, Mandy Mastrovita, and Greer Martin.

This collection uses primary sources to explore the Transatlantic Slave Trade. Digital Public Library of America Primary Source Sets are designed to help students develop their critical thinking skills and draw diverse material from libraries, archives, and museums across the United States. Each set includes an overview, ten to fifteen primary sources, links to related resources, and a teaching guide. These sets were created and reviewed by the teachers on the DPLA's Education Advisory Committee.

In 1862, Congress passed and President Lincoln signed the Pacific Railroad Bill, which granted public land and funds to build a transcontinental railroad. The Central Pacific Railroad would lay tracks from California heading east, and the Union Pacific Railroad would lay tracks from the Missouri River west. The photograph taken in Placer County, "Grading the Central Pacific Railroad," shows some of the construction. Work on the railroad was physically difficult and at times dangerous, and attracting workers was a challenge. The majority of the Central Pacific's laborers were Chinese. A Chinese worker is shown in the image "Heading (top cut) of East Portal, Tunnel No. 8." Both railroad companies actively recruited Chinese laborers because they were regarded as hard workers and were willing to accept a lower wage than white workers, mostly Irish immigrants. As construction progressed, the Central Pacific and the Union Pacific competed to see which could lay the most track each day. A photograph of a sign near Promontory Park, Utah, commemorates the day that Central Pacific crews laid an unprecedented 10 miles of track. The meeting of the two sets of tracks ? the "gold spike" ceremony ? took place on May 10, 1869. Several photographs and drawings depict this historic moment. Now the country was connected as never before: a journey between San Francisco and New York that previously took up to six months now took only days. The photograph "High Bridge in Loop," from Views from a Trip to California, shows a train passing quickly through a mountain pass. The transcontinental railroad allowed people to travel more, farther, and in pleasant conditions, as reflected in the photograph "Commissary Car, 'Elkhorn Club.'" The photograph "Knights of Pythias at the Santa Fe Railway Station, Anaheim" shows an example of the popularity of trains. Even as the transcontinental railroad brought the new country together, it brought change to the world of Native Americans. The tracks ran through a number of tribal territories, bringing into conflict cultures that held very different views of the land and how it might be used and lived on. The painting The First Train, by Herbert Schuyler, depicts three Indians pointing past their encampment at a train in the far distance. The railroad also brought an increasing number of European Americans west. One consequence of this influx was the depletion of the buffalo herds, a major food source for Plains Indians. European Americans would often shoot buffalo for sport from the train; by 1880, the buffalo were mostly gone and Plains Indians had been gathered onto reservations. Millions of acres of open grassland were being settled by the people moving west. Eventually, much of this land became the farmland that fed a growing nation. The transcontinental railroad opened up the West to the rest of the country, even if they never made the trip themselves. A Currier & Ives hand-colored lithograph depicts a train running along the Truckee River in Northern California. The San Francisco publishing firm of Lawrence & Houseworth hired photographers and published photographic tourist catalogs containing views of the West, which they sold commercially. The railroad took hold in popular culture, as shown by sheet music for the song "New Express Galop [sic]." There was even a railroad board game illustrating "Railroads Between New York and San Francisco, California, with Scenes on the Way."

Contents :
1 History
2 Overview
2.1 Extending the definitions
2.2 Mnemonics
2.3 Calculating trigonometric functions
3 Applications
4 Pythagorean identities
5 Angle transformation formulae
6 Common formulae
6.1 Law of sines
6.2 Law of cosines
6.3 Law of tangents
6.4 Euler's formula
7 See also
8 References
9 Bibliography

Trinidad, CO Mining Town. Western Mining History presents a brief summary of Colorado's Historical Mining Towns with links to additional Colorado resources for a mining town database and mines by county. Western Mining History is an historical site that provides information on mining, mining towns, the gold and silver rush, and Photos and maps of the western United States. This is a strong primary source resource that can be used for a variety of class research projects. Consider becoming a member or making a donation to help further the work of the site.

Tsetse flies are important vectors of human and animal diseases that adversely impact life in sub-Sahara Africa. A community of tsetse researchers (International Glossina Genome Initiative) have been working to obtain the full genome sequence of the tsetse species Glossina morsitans morsitans. The group have also mined the genome data to advance knowledge on functional aspects of tsetse and African trypanosome biology. This collection describes findings on tsetse's salivary gland biology, olfactory chemistry, lactation process, acquaporin proteins that play a role in lactation, oxidative stress responses during pregnancy, gut peritrophic matrix analysis and horizontal transfer events discovered in tsetse's genome from the symbiont Wolbachia. Further manuscripts reflect on the historical aspects of sleeping sickness epidemics that have plagued sub-Sahara in the 20th century.

Tungsten, CO Mining Town. Western Mining History presents a brief summary of Colorado's Historical Mining Towns with links to additional Colorado resources for a mining town database and mines by county. Western Mining History is an historical site that provides information on mining, mining towns, the gold and silver rush, and Photos and maps of the western United States. This is a strong primary source resource that can be used for a variety of class research projects. Consider becoming a member or making a donation to help further the work of the site.

Turret, CO Mining Town. Western Mining History presents a brief summary of Colorado's Historical Mining Towns with links to additional Colorado resources for a mining town database and mines by county. Western Mining History is an historical site that provides information on mining, mining towns, the gold and silver rush, and Photos and maps of the western United States. This is a strong primary source resource that can be used for a variety of class research projects. Consider becoming a member or making a donation to help further the work of the site.

The National Park Service presents a short description of the history of 20 Mule Team Borax freight wagon teams. This resource also includes an imagined conversation with one of the muleskinners who drove the Twenty Mule Team Borax wagons. These wagons hauled up to 40 tons of Borax in Death Valley, California.

This collection uses primary sources to explore Harriet Beecher Stowe's Uncle Tom's Cabin. Digital Public Library of America Primary Source Sets are designed to help students develop their critical thinking skills and draw diverse material from libraries, archives, and museums across the United States. Each set includes an overview, ten to fifteen primary sources, links to related resources, and a teaching guide. These sets were created and reviewed by the teachers on the DPLA's Education Advisory Committee.

Western Mining History presents a short tour of underground hoist construction at the US Mine in Bingham, Utah. Western Mining History is an historical site that provides databases, information on mining, mining towns, gold and Photos and maps of the western United States. Consider becoming a member or making a donation to help further the work of the site.

This collection uses primary sources to explore the Underground Railroad and the Fugitive Slave Act of 1850. Digital Public Library of America Primary Source Sets are designed to help students develop their critical thinking skills and draw diverse material from libraries, archives, and museums across the United States. Each set includes an overview, ten to fifteen primary sources, links to related resources, and a teaching guide. These sets were created and reviewed by the teachers on the DPLA's Education Advisory Committee.

The unit has two parts. In each, students dive into inquiry to answer the compelling questions:

1. Who are some of our closest tribal neighbors, and what have they been their lifeways since time immemorial?
2. Why do people explore, and how does this lead to expansion?

Part 1 is focused on the examination of the northwest and some of the original inhabitants. Through these questions students will learn about the culture of some of their closest tribal neighbors, the Spokane Indians. The final project for Part 1 is a cultural investigation display, in which students will show what they know about the culture of the Spokane Tribe.

In Part 2, Students will also learn about forces that brought change to the northwest: fur trade era and exploration. Students will ultimately learn about the Corps of Discovery and the Oregon Trail and know the impact each had on the west. Students will finish Part 2 with a timeline activity that will reflect choice and build upon student strengths according to their skill set.

Finally, a lesson on a Tribe of the Columbia Plateau is offered as an extension, but it is strongly recommended that students get to experience this lesson.

Note that the emphasis here is on the Spokane Tribe as one of our closest tribal neighbors. In no way is this an exhaustive study nor should the tribal cultures be generalized to other tribes of the region. We understand that each tribe in our region and North America was and continues to be unique in its culture, practices, lifeways, and traditions.

This collection uses primary sources to explore the United Farm Workers and the Delano Grape Strike. Digital Public Library of America Primary Source Sets are designed to help students develop their critical thinking skills and draw diverse material from libraries, archives, and museums across the United States. Each set includes an overview, ten to fifteen primary sources, links to related resources, and a teaching guide. These sets were created and reviewed by the teachers on the DPLA's Education Advisory Committee.

The Uranium Boom: Stop 9 Museum of the West Virtual Tour. Watch this short video to learn about a Museum of the West exhibit or collection to preview your field trip or for a virtual field trip if you are unable to attend in person. The Museum of the West is part of the Museums of Westen Colorado. The Uranium boom made Grand Junction famous. Its nickname became “The City That Glows.” David Bailey explains the effect the Uranium boom had on Grand Junction.

In 1853, the City of New York set aside hundreds of acres of swampland in the middle of Manhattan, with the idea that this uninhabitable space could serve a practical, public purpose. Today, we know that area as Central Park, one of the most widely visited and celebrated public spaces in the country. The then-unknown park designer who won the bid to design Central Park, Frederick Law Olmsted, would go on to inspire and revolutionize urban park design in the United States. The work of Olmsted and other early parks pioneers, building on older concepts like town squares, would spur the growth of urban parks large and small nationwide. Benefiting from new innovations in design, these parks serve as community centers and defining features of cities and towns across the country. Urban parks have continually adapted to meet the needs of the publics they serve, evolving, for example, from places to simply enjoy nature into recreation sites that offer activities and equipment. More than just sites for leisure, they also play a broader role in supporting community engagement by providing places for civic participation, enhancing quality of life and property values, and offering safe, healthy, and convenient recreation options. This exhibition was created as part of the DPLA’s Public Library Partnerships Project by collaborators from the Minnesota Digital Library. Exhibition Coordinator: Carla Urban.