Igneous petrology most common application of stratigraphic dating on volcanic rocks. In petrology the mineral clinopyroxene is used for temperature and pressure calculations of the magma that produced igneous rock containing this mineral. Clinopyroxene thermobarometry is one of several geothermobarometers. Two things make this method especially useful: first, clinopyroxene is a common phenocryst in igneous rocks easy to identify; and secondly, the crystallization of the jadeite component of clinopyroxene implies a growth in molar volume being thus a good indicator of pressure. Most contemporary ground breaking in igneous petrology has been published in prestigious American and British scientific journals of worldwide circulation
What to the Slave Is the Fourth of July? What to the Slave Is the Fourth of July? "What to the Slave Is the Fourth of July?" is the title now given to a speech by Frederick Douglass delivered on July 5, 1852, in Corinthian Hall, Rochester, New York, addressing the Rochester Ladies' Anti-Slavery Society. The speech is perhaps the most widely known of all of Frederick Douglass' writings save his autobiographies. Many copies of one section of it, beginning in para. 32, have been circulated online. Due to this and the variant titles given to it in various places, and the fact that it is called a July