Blashfield, Jean F

Defines trace elements and discusses how they affect life on the planet.

Explains what the chemical element chlorine is, and discusses its importance to humans.

Describes the chemical make-up of sulfur, where it is found, and its uses; also includes a periodic table, a glossary, and a bibliography.

Notes the importance of potassium to life and industry.

Notes the importance of phosphorus to plants and animals.

An introduction to the geography, history, natural resources, economy, culture, and people of Wisconsin.

Text and photographs discuss the history and natural environment of the Galapagos Islands, and what can be done to keep them safe from the effects of human civilization.

Explores the history of slavery in the United States, from the first slaves brought to Jamestown in 1619 to the ending of slavery in the Civil War and beyond to the Civil Rights Movement of the 1960s.

A biography of Abraham Lincoln, the sixteenth president of the United States and the man responsible for seeing the Union through the Civil War.

Describes the geography, plants, animals, history, economy, religions, culture, sports, arts, and people of Delaware.