The editing widgets for <pages> and <pagequality> tags are currently badly displayed and, so, unusable because of a JS error.
To reproduce for the <pagequality> tag go to https://en.wikisource.org/wiki/Page:Scientific_American_-_Series_1_-_Volume_001_-_Issue_01.pdf/3 click "edit" and then try to edit the <pagequality> tag (the one in green saying "This page has been validated.".
For the <pages> tag go to https://en.wikisource.org/wiki/Scientific_American/Series_1/Volume_1/Issue_1/New_Article_of_Export?veaction=edit and try to edit the text (starting with "New article for export").