In the early 19th century most of the working class lived on plain food bread, butter, potatoes and bacon. Butcher's meat was a luxury. However food greatly improved in the late 19th century. Railways and steamships made it possible to import cheap grain from North America so bread became cheaper. Refrigeration made it possible to import cheap meat from Argentina and Australia. Consumption of sugar also increased. By the end of the 19th century most people were eating better food. Furthermore in the late 19th century canned food first became widely available. The rotary can opener was invented in 1870 by William Lyman. Furthermore in the 1870s margarine, a cheap substitute for butter, was invented. Several new biscuits were invented in the 19th century including the Garibaldi (1861), the cream cracker (1885) and the Digestive (1892). The first chocolate bar was made in 1847. Milk chocolate was invented in 1875.