Select Quotes ⇒ Primes in the Quotes submenu of the Convert menu to convert all quotes in the selected text into primes. If there is no selection, the quotes on the line that the cursor is on are converted.
The prime (′) is the correct symbol to use to indicate units such as feet or arcminutes. The double prime (″) represents inches and arcseconds. Triple primes (‴) represent a ligne (1/12 of an inch) or a third (1/60 of a second). Quadruple primes represent a fourth (1/60 of a third). In mathematics, primes are used to indicate derivatives. In music, primes represent octaves. The middle C is c′, while c″ is one octave above c′ and c‴ is two octaves higher.
5′8″ (using primes) is the correct way to write 5 feet 8 inches. 5'8" is how you would enter 5 feet 8 inches on a keyboard. You’d have to leave it as that in a plain ASCII text file. 5’8” (using high commas) is nonsense produced by (automatic) straight to smart quote conversion.
Depending on the font you’re using, the difference between a prime (′) and a high comma (’) can be subtle. The prime is straight while the high comma is curved like a little 9. Even if your font doesn’t give high commas much curvature, you should take care to use the correct symbol. If you switch fonts later, the difference can be more glaring. Arial is a font that makes primes and quotes look rather different. If somebody uses Convert|Quotes|Replace Smart Quotes to change the quotation style later, high commas may be replaced but primes will stay as primes.
The Quotes ⇒ Primes command converts straight quotes, high commas (’ and ”), turned commas (‘ and “), and all the characters you selected in the five “straight to smart quotes” drop-down lists in Convert|Quotes|Quotation Style into primes. This ensures that the straight quotes you enter on the keyboard are converted into primes, even if those straight quotes were already converted into smart quotes by Convert|Quotes|Auto Adjust Quotes.
Individual single quotes are converted into single primes. Two consecutive single quotes and double quotes are converted into double primes. Three consecutive single quotes, a single and double quote pair, and a double and single quote pair are converted into triple primes.
Quotes ⇒ Primes does not produce quadruple primes. Most fonts included with Windows do not support them. Two consecutive double quotes become two double primes. Four consecutive single quotes become a triple prime followed by a single prime.
Quotes ⇒ Primes converts backticks (`) into reverse primes. This only works if you did not allow Convert|Quotes|Auto Adjust Quotes to convert backticks into smart quotes first. Since Auto Adjust Quotes waits until you move away from the line you were editing, you can use Quotes ⇒ Primes immediately after entering the backticks to convert them into primes. Many fonts included with Windows do not support reverse primes, however.
Convert|Quotes|Primes ⇒ Quotes