Petrography rock was affixed to a microscope slide and then ground so thin that light could be transmitted through mineral grains that otherwise appeared opaque. The position of adjoining grains was not disturbed, thus permitting analysis of rock texture. Thin section petrography became the standard method of rock study. Since textural details contribute greatly to knowledge of the sequence of crystallization of the various mineral constituents in a rock, petrography progressed into petrogenesis and ultimately into petrology. It was in Europe, principally in Germany, that petrography advanced in the last half of the nineteenth century. The macroscopic characters of rocks, those
What Is History? that historians deem unimportant, and "historical facts", information that the historians have decided is important. Carr contended that historians arbitrarily determine which of the "facts of the past" to turn into "historical facts" according to their own biases and agendas. For this reason, Carr argued that Leopold von Ranke's famous dictum "wie es eigentlich gewesen" (show what actually happened) was wrong because it presumed that the "facts" influenced what the historian wrote, rather than the historian choosing what "facts of the past" he or she intended to turn into "historical facts". At the same time, Carr argued that the study