Mass-to-charge ratio refers to the molecular or atomic mass number and "z" to the charge number of the ion; however, the quantity of "m"/"z" is dimensionless by definition. An ion of 100 atomic mass units ("m" = 100) carrying two charges ("z" = 2) will be observed at "m"/"z" = 50. 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
John (given name) masculine name in the United Kingdom, but by 2004 it had fallen out of the top 50 names for newborn boys in England and Wales. By contrast Jack, which was a nickname for John but is now established as a name in its own right, was the most popular name given to newborn boys in England and Wales every year from 1995 to 2005. However, "John" has not been a popular one for members of the royal family. The memory of King John is tainted by negative depictions of his turbulent reign and troublesome personality and by his role as