−The image shows printed page 8, PDF page 20, of a public-domain scan of the 1882 edition. Its preface records that lithographed copies were distributed in 1870. The passage mentions higher powers before taking the square as the default, so the 1870 distribution and the 1882 edition quoted here are identified separately. Edition record, preface.
+The image shows printed page 8 (PDF page 20) of the 1882 edition, whose preface records that lithographed copies were first distributed in 1870. Edition record, preface.
