History
In the 19th century, the mass-to-charge ratios of some ions were measured by electrochemical methods. In 1897, the mass-to-charge ratio of the electron was first measured by J. J. Thomson. By doing this, he showed that the electron was in fact a particle with a mass and a charge, and that its mass-to-charge ratio was much smaller than that of the hydrogen ion H+. In 1898, Wilhelm Wien separated ions (canal rays) according to their mass-to-charge ratio with an ion optical device with superimposed electric and magnetic fields (Wien filter). In 1901 Walter Kaufman measured the increase of electromagnetic mass of fast electrons (Kaufmann–Bucherer–Neumann experiments), or relativistic mass increase in modern terms. In 1913, Thomson measured the mass-to-charge ratio of ions with an instrument he called a parabola spectrograph. Today, an instrument that measures the mass-to-charge ratio of charged particles is called a mass spectrometer.
Read more about this topic: Mass-to-charge Ratio
Famous quotes containing the word history:
“Three million of such stones would be needed before the work was done. Three million stones of an average weight of 5,000 pounds, every stone cut precisely to fit into its destined place in the great pyramid. From the quarries they pulled the stones across the desert to the banks of the Nile. Never in the history of the world had so great a task been performed. Their faith gave them strength, and their joy gave them song.”
—William Faulkner (1897–1962)
“If you look at history you’ll find that no state has been so plagued by its rulers as when power has fallen into the hands of some dabbler in philosophy or literary addict.”
—Desiderius Erasmus (c. 1466–1536)
“Don’t you realize that this is a new empire? Why, folks, there’s never been anything like this since creation. Creation, huh, that took six days, this was done in one. History made in an hour. Why it’s a miracle out of the Old Testament!”
—Howard Estabrook (1884–1978)