From: Herbert Prinz
Date: 2017 Aug 10, 11:40 -0700
The 1874 edition of Bowditch has been printed from the same stereotyped plates as the edition of 1867. (See Notice after titel page, without page number). And this provides only an upper limit to the last revision of the text! It is probably safe to assume that this edition of Bowditch reflects the actual practice at sea from around 1850. E.g. Sumner's work and the line of bearing is just briefly touched on in one chapter. I also notice the similarity of the wording in the two texts you reference. Many authors of text books just copied from each other, used little feedback from practitioners; or were somewhat behind integrating it.
What do the log books tell us on the usage of dates?