When I was a child, in a large family, we made cakes every day. There was never baking powder in our house - it was years before I learnt of its existence. We used a teaspoonful of cream of tartar and half a teaspoonful of bicarb. If we had any sour milk (our milk wasn't pasteurised when I was a child), we made scones using just bicarb in the flour before rubbing in the butter, with the sour milk acting as the acid to react with it and make the mixture rise.