Continuing on with my series of typographic symbols…Apostrophes and Primes.

Apostrophes and Quotations Marks vs. Primes and Double Primes
A common mistake that people make is the difference between these similar markings. Everyone is familiar with apostrophes and quotation marks, but what many people overlook is that some computer applications and internet browsers will turn the marks in what are called primes. A prime or double prime are often used to signify feet and inches or hours and minutes, a prime also has mathematical uses. As you can see in this illustration the visual different between the two is the curvature of the apostrophe and quotation marks.