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
Nature study students, who were influenced by this philosophy, went on to provide the nature study knowledge in public schools. It was Agassiz who coined the phrase, "Study nature, not books." Nature study can be described as "conceiving of the movement as a loose coalition of communities composed of individuals, societies, and institutions able to find some common ground in the study and appreciation of the natural world". In "Leaflet I: What Is Nature-Study?" from a 1904 collection nature study lessons, Liberty Hyde Bailey presented the following description of nature study: NATURE-STUDY, as a process, is seeing the things that one looks