A 2.5×2.5×10‐cm hydrogen bubble chamber has been developed for experiments on the scattering of particles from the 450 Mev synchrocyclotron. Seventy‐five thousand pictures have been taken at the rate of one every two seconds and are being scanned at the rate of two thousand per day. The average track length per picture is about one gram per square centimeter. The characteristics of the bubble chamber are described and examples of the pictures are shown.