The British Library's Endangered Archives Blog has an article about a new online collection.
This Hume family arrived in Argentina in the late 19th century and founded the engineering firm ‘Hume Brothers’ in 1880; their main work building roads, quarries, bridges, railways, stations, factories not just in Argentina but in Brazil, Chile and Uruguay, too.
Disappointingly, the blog doesn't mention the founders names, dates of birth or birthplace.
Some Humes are mentioned in the folders, including Albert Stewart Hume, 1873- c1965, Mariana Hume, 1928-, Diana Hume, 1930-, Anne Elizabeth Hume, 1925-.
66 Squadron's sad account of Sidney Stewart Hume, born in Buenos Aires on 1 September 1885, mentions that his father was Alexander Hume, who was a partner in Hume Brothers.
See the Index to the Hume Family Collection.