 Although the advertisement claimed that these articles would be included in this manner, they were not, and the author of the preface to the 7th edition states that none of this material entered the main body until that edition, and even gives a list of the articles which were.Almost no changes were made to the text, it was basically a remake of the 5th with very minor updates.All in all, the fourth, fifth, and sixth editions are virtually the same as each other.