Doctor Procter's Fart Powder

I am reading this book called Doctor Procter's Fart Powder. It is a funny book. There is a new kid, Nelly to the neighborhood and he becomes friends with the girl next door named Lisa. One day Nelly goes to the house across the street and meets Doctor Procter and sees the scientist's lastest invention, a fart powder that doesn't smell. Well Lisa gets to find out about the invention and they have to find a way to use it. Well they start selling it for 50 cents a bag at school and it becomes a hit. I am not going to spoil anymore.