I have read a few papers that were written in the early 1900's where their concentration measurements are M/4, M/8, M/16, M/32, M/256. I am not sure what this means and I was wondering if anyone could relate these concentration measurements to normal concentration measurements we use now, such as Molar. An example of a paper that used this method of measuring concentration is linked below. http://ebm.rsmjournals.com/content/23/1/66.extract [Broken] I have searched google and had no luck finding what the M/number concentration measurement means. If anyone could find out what this means it would really help.