the city of Naples herself, a rather odd phenomenon in a time when much of Europe experienced the Industrial Revolution. While underdeveloped compared to Northwest Italy and contemporary Western European countries at the time of unification in 1861, the average wage of the Two Sicilies was actually higher than Central Italy and on par with Northeast Italy. The island of Sicily, in particular, was richer than the mainland part of the kingdom and its wages were very close to the northwest's. The Divergence increased massively after unification however, due to the complete collapse of the South's economy. Agriculture As registered in the 1827 census, for the Neapolitan (continental) part of the kingdom, 1,475,314 of the male population were listed as husbandmen which traditionally consisted of three classes the Borgesi (or yeomanry), the Inquilani (or small-farmers) and the Contadini (or peasantry), along with 65,225 listed as shepherds. Wheat, wine, olive oil and cotton were the chief products with an annual production, as recorded in 1844, of 67 million liters of olive oil largely produced in Apulia and Calabria and loaded for export at Gallipoli along with 191 million liters of wine that were for the most part consumed domestically. On the island of Sicily, in 1839, due to less arable lands, the output was much smaller than on the mainland yet approximately 115,000 acres of vineyards and about 260,000 acres of orchards, mainly fig, orange and citrus, were cultivated. Industry Industry was the largest source of income if compared with the other preunitarian states. One of the most important industrial complexes in the kingdom was the shipyard of Castellammare di Stabia, which employed 1800 workers. The engineering factory of Pietrarsa was the largest industrial plant in the Italian peninsula, producing tools, cannons, rails, locomotives. The complex also included a school for train drivers, and naval engineers and, thanks to this school, the kingdom was able to replace the English personnel who had been necessary until then. The first steamboat with screw propulsion known in the Mediterranean Sea was the "Giglio delle Onde", with mail delivery and passenger transport purposes after 1847. In Calabria, the Fonderia Ferdinandea was a large foundry where cast iron was produced. The Reali ferriere ed Officine di Mongiana was an iron foundry and weapons factory. Founded in 1770, it employed 1600 workers in 1860 and closed in 1880. In Sicily (near Catania and Agrigento), sulfur was mined