the first five editions. The differences were published along with an edited sixth edition in 1904. They found minor but numerous differences (including the addition of many footnotes) between the first and the second editions; the differences between the second and third editions are major. In 1784, Smith annexed these first two editions with the publication of Additions and Corrections to the First and Second Editions of Dr. Adam Smith's Inquiry into the Nature and Causes of the Wealth of Nations, and he also had published the three-volume third edition of the Wealth of Nations, which incorporated Additions and Corrections and, for the first time, an index. Among other things, the Additions and Corrections included entirely new sections, particularly to book 4, chapters 4 and 5, and to book 5, chapter 1, as well as an additional chapter (8), "Conclusion of the Mercantile System", in book 4. The fourth edition, published in 1786, had only slight differences from the third edition, and Smith himself says in the Advertisement at the beginning of the book, "I have made no alterations of any kind." Finally, Cannan notes only trivial differences between the fourth and fifth editions—a set of misprints being removed from the fourth and a different set of misprints being introduced. Synopsis Book I: Of the Causes of Improvement in the productive Powers of Labour Of the Division of Labour: Division of labour has caused a greater increase in production than any other factor. This diversification is greatest for nations with more industry and improvement, and is responsible for "universal opulence" in those countries. This is in part due to increased quality of production, but more importantly because of increased efficiency of production, leading to a higher nominal output of units produced per time unit. Agriculture is less amenable than manufacturing to division of labour; hence, rich nations are not so far ahead of poor nations in agriculture as in manufacturing. Of the Principle which gives Occasion to the Division of Labour: Division of labour arises not from innate wisdom, but from humans' propensity to barter. That the Division of Labour is Limited by the Extent of the Market: Limited opportunity for exchange discourages division of labour. Because "water-carriage" (i.e. transportation) extends the market, division of labour, with its improvements, comes earliest to cities near waterways. Civilization began around the highly navigable Mediterranean Sea. Of the Origin and Use of Money: