Search

Search results

Displaying 211 - 220

Ross, Alexander

(Encyclopedia) Ross, Alexander, 1783–1856, Canadian fur trader and pioneer, b. Scotland. He went to Canada in 1805, taught school in Upper Canada, and in 1810 left for Oregon as a clerk in John Jacob…

nitrogen mustard

(Encyclopedia) nitrogen mustard, any of various poisonous compounds originally developed for military use (see poison gas). Like mustard gas and lewisite, it is a vesicant (blistering agent). In the…

Uslar Pietri, Arturo

(Encyclopedia) Uslar Pietri, ArturoUslar Pietri, Arturoärt&oomacr;ˈrō &oomacr;sˈlär pyāˈtrē [key], 1906–2001, Venezuelan novelist and essayist. Uslar Pietri is considered one of the most…

Permian period

(Encyclopedia) Permian periodPermian periodpûrˈmēən [key] [from Perm, Russia], sixth and last period of the Paleozoic era (see Geologic Timescale, tablegeologic timescale, table) from 250 to 290…

Value: Tints and Shades

The lightness or darkness of a color is called its value. You can find the values of a color by making its tints and shades. Tints are light values that are made by mixing a color with white. For…

DK Science: Algae

FOREST OF KELPTYPES OF SEAWEEDALGAL OVERKILLPHYTOPLANKTONFIND OUT MOREAlgae are simple organisms that make food from sunlight by photosynthesis, but lack the roots, stems, and leaves of proper…

Rivers of the United States

(350 or more miles long)Alabama-Coosa (600 mi.; 966 km): From junction of Oostanula and Etowah R. in Georgia to Mobile R.Altamaha-Ocmulgee (392 mi.; 631 km): From junction of Yellow R. and South R…

Erythraean Sea

(Encyclopedia) Erythraean SeaErythraean Seaĕrĭthrēˈən [key], name of unclear origin anciently applied to the Indian Ocean, later to the Arabian Gulf, and finally to the Red Sea.

jasper, type of quartz

(Encyclopedia) jasper, opaque, impure cryptocrystalline quartz, usually red, but also yellow, green, and grayish blue. It is used as a gem. Ribbon jasper has the colors in stripes.

Sherman

(Encyclopedia) Sherman, city (1990 pop. 31,601), seat of Grayson co., N Tex., near the Red River; inc. 1858. Originally on a stagecoach route, it is a highway and railroad junction. Manufactures…