Summary Results have been given to show that hy- drogen is highly efficient as a carrier gas for the dehydrogenation of borneol vapor over reduced copper, particularly in respect to catalyst life and purity of product. Optimum conditions with respect to tem- perature and time have been established for the reaction thus conducted. ... 3. Results have been given to show that car- bon dioxide is in most respects inferior to hydro- gen as a carrier. 4. Preliminary experiments ...