 For other examples, the 4th edition has a 96-page article "Conchology", which listing does not appear in the 3rd or its supplement, and "Erpetology", 60 pages long in the 4th edition, with a 3-page index, is a new listing as well.After "Science" is a new 24-page article "Amusements In Science", which is a virtual Mr. Wizard for the opening of the 19th century.The majority of copy in the 4th edition, however, is unchanged from the 3rd.