This section is from the book "Soyer's Standard Cookery", by Nicolas Soyer. Also available from Amazon: Soyer's Standard Cookery.
Mix cocoa, sugar and a pinch of salt, dilute with one-half cup boiling water to make smooth paste, add remaining water, and boil one minute; turn into scalded milk and beat three minutes, when froth will form, preventing scum, which is so unsightly; this is known as milling.
Take three tablespoon fuls of cocoa, one-quarter cup of sugar, a few grains of salt, four cups of milk, three-quarters cup of boiling water.
Mix cocoa, sugar, and salt, adding enough boiling water to make a smooth paste; add remaining water and boil two minutes; pour into scalded milk. Beat three minutes, using egg-beater.

How To Make Good Coffee. No. 2. (See Also P. 398.) Showing the Coffee Pot, complete, standing in shallow pan of hot water. When ready, the infuser is removed, the lid placed on pot, and carried to the table.
Take one and a half squares of chocolate, one-quarter cup of sugar, few grains of salt, one cup boiling water, three cups of milk.
Melt chocolate in small saucepan placed over hot water, add sugar, salt, and gradually boiling water; when smooth, place on range and boil one minute; add to scalded milk, mill, and serve in chocolate cups with whipped cream. One and one-half ounces vanilla chocolate may be substituted for chocolate; being sweetened, less sugar is required.
(Another Method.) Prepare same as previous recipe, substituting one can evaporated cream or condensed milk diluted with four cups boiling water in place of three cups of milk.
 
Continue to: