I like to bake lemon cakes on a regular basis. I looked at the recipe for lemon cake and the book uses carbonate of ammonia instead of baking powder. What's interesting is that it releases a strong smell a ammonia as the cake bakes. I can't even imagine having to deal with that smell in one of my cakes today. It's funny, we think that we have an idea of what it was like to live in previous times but I suspect that we would be completely lost if we somehow went back. Just baking a cake would have been such a different experience now imagine everything else.