From 1912:

Two cups of milk two eggs, three cups of sifted flour, two even teaspoonfuls of baking powder, a saltspoonful of salt, one tablespoonful of melted butter.
Sift baking powder and salt three times with the flour. Beat yolks and whites together and very light. Add the milk to these, then the melted butter, lastly the flour. Beat hard for one minute.
Rub the waffle irons with salt, then wash and wipe and set at the side of the range for an hour to heat them gradually. Thus ”seasoned” they will not adhere to the batter after they are greased well. At the end of the hour move to the front over a hole and grease with lard tied up in a bit of cloth. Try a little of the batter to test the heat before baking a waffle.