Trace gas Trace gas The most abundant gases in the atmosphere are nitrogen (78.1%), oxygen (20.9%), and argon (0.934%). Combined, oxygen, argon, and nitrogen make up 99.934% of the gases in the atmosphere (not including water vapor). The other gases that are not part of the 99.934% of the atmosphere are called trace gases. The abundance of a trace gas can range from a few parts per trillion (ppt) by volume to several hundred parts per million by volume (ppmv). When a trace gas is added into the atmosphere, that process is called a "source". There are two possible types of sources
Copia: Foundations of the Abundant Style 11 separate methods of using abundant subject matter. Here Erasmus uses a more dialectical approach, and typically gives a few lines of theory followed by many illustrations from classical sources. Erasmus purpose was to contribute to the existing scholarship on style. To that end, he put forth in "De Copia" that style must be abundant in order to be effective, and that the abundance consists of two primary elements: variety of expression and variety of subject matter. Variety, he says, “is so powerful in every sphere that there is absolutely nothing, however brilliant, which is not dimmed if not commended