In Foreign Colors -- We are used to seeing the R.A.F. colors on American-built planes, but here is something unusual-a British designed bomber built for the American Air Force. It is, of course, the famous Canberra jet bomber, built under licence in U.S.A. by the martin Aircraft Company, and named the Martin B-57B It is seen pith a full complement explosives-four napalm tanks, and eight 5-inch high velocity rockets, four on either side. The D57B also mounts eight 50-calibre machine guns firing