Which they retain; and hollow articles, such as playing balls or injection bottles, are vulcanized in iron or brass moulds, tinned inside and very slightly greased.
Machinery, provisions, largely in the form of tinned and otherwise preserved food, and liquors, clothing, textiles and hardware, chemicals and dynamite, iron and steel work and timber, and jewelry are the chief items in the imports.
The most important form of the operation is making tinned from ordinary sheet iron (making what is called "sheet tin").
To tin cast-iron articles they must be decarburetted superficially by ignition within a bath of ferric oxide (powdered haematite or similar material), then cleaned with acid, and tinned by immersion, as explained above.
In the "Lusitania," the steam traverses vertical copper coils tinned inside and outside; the coils are crescent-shaped, a form which gives a greater condensing surface and makes the coils self-scaling.