Stationary, metallic sphere with dark central spot seen high in northern sky

My age at the time:13. Location where sighting occured: S.W. corner of East Avenue and Ellis Street, Stevens Point, WI. Date and time: late May, 1968, 7:50 AM to 8:00 AM. Shortly before my first class of the day began at Emerson junior high school, I and 2-to-3 friends saw a bright metallic sphere (reflecting the morning sun) with a dark central spot, high in the northern sky. The object remained stationary as clouds passed both in front of and behind it. We observed the object for about ten minutes, then went into the school building, where we called the police. The officer on duty dismissed our report as a weather balloon.
Date is approximate.  PD