I currently work for a publisher of textbooks as a metricator, or person who converts United States customary units like ft, mi and gal to SI units like m, km and L. I promise I’ll save any comments on the two systems for later.
Making changes is done by marking up PDF files of manuscripts or previous editions using the “comment” feature in Acrobat. In cases of equations or complex typesetting, Acrobat or some application attempted to OCR the contents. In one particular case, this leads to a minor distinction, unimportant to all but the most sedulous observers or nitpickers: The difference between a shilling mark or solidus (∕) and a forward slash (/).
The shilling mark was (According to WikipediA anyway1) derived from the medial S used to indicate the number of shillings in a price that was denominated in the old pounds-shillings-pence (Lsd) system of currency used in the United Kingdom and its sometime colonies. For example, 19 guineas and six pence would be written 19l. 19ſ. 6d. and read “nineteen pounds, nineteen shillings, six pence”. Over time, the “ſ.” turned into a slash, so: 19l. 19∕. 6d. This ended up: 19l. 19∕6 or “nineteen pounds, nineteen and six”.
The solidus (I love that word) is still around in Unicode and could be used in place of the forward slash in fractions. I’ve only ever seen this in OCR’d files that had an overly zealous character palette to choose from. Unfortunately, sometimes the software would choose to use the solidus, and other times decide that the symbol on the paper was actually a slash. Minor matter since they look similar. Not so minor if you work for the publisher and keep seeing the division glyph change from one to the other in the same paragraph.
So, if you OCR documents with fractions set on a line, make sure you’ve got “1/6” (one sixth) and not “1∕6” (one shilling and sixpence of an obsolete currency system).