This period witnessed a complete break with the trading past. Glasgow became a leading industrial city and though its industries demanded raw materials these were often now home produced. On the other hand foodstuffs were a major part of import trades, especially with the opening up of North and South American and Australasian grasslands producing wheat and flour; live, canned or frozen meat; and butter and cheese (with symbiotic requirements for infrastructural and settler support). However, while undeniably dependent on imports, Glasgow became most obviously an exporting port: the "second city of the empire" inextricably linked with imperial expansion.
The opening up of North America provided grain, wood and cotton. In the second half of the 19th century Glasgow exported "coal and goods", iron bars, tubes, boilers, castings, railway metals and engines, iron and steel steamers, iron ceilings for imperial bungalows and tin tabernacles for missionaries. Industrial goods went to North, Central and South America, the Middle East, India and Asia. European trade revived, with coal and manufactures to France, Holland and Germany, and also exchanged for Spanish iron ore and Mediterranean sulphur. "Lighter" trades involved books, paper, pen-nibs, paint and Tennents' "Export" from the 1870s.
This booming trade depended on the initiatives of merchants and the availability of steam shipping. So exports developed with the regular lines out of Glasgow to the Americas, Australasia and the Far East, but also the Glasgow-owned server lines – the Irrawaddy Flotilla, the Yangtse Squadron, lines on the Burmese and China coasts. Understandably, the Clyde Navigation Trust's list of goods exported from the Clyde covered fifteen closely printed pages in 1910/11.