You can see it by putting tape on your axis point and observing the tape as the ball travels down the lane.
After throwing the ball and retreiving it from the return, look for the oil ring. There may be several rings that intersect at two points depending upon how the ball was drilled for reaction.
Put the ball in an ashtray so that the ring is on the top half of the ball and level to the floor. If several rings, use the ring closest to the thumb hole.
The point at the top and bottom of the ball is your axis of rotation. Place a piece of white tape (white ball tape used to adjust hole size will do) at the very top of the ball.
When you throw the ball, you will should see the tape as a solid spinning dot. If it looks like a small ring, you may need to adjust the tape position until you find the axis point.
If the ball had several rings, the tape should look like a solid dot, then begin to 'wobble'. This is called axis migration and is evident on balls drilled for more reaction on the back end.
If the dot is spinning parallel to the lane and pointed to the side wall of the bowling center you have zero degrees of axis tilt (dot parallel to the lane) and zero degress axis of rotation (dot pointed toward the wall).
As the dot is directed more toward the lane, the more axis tilt. As the dot is pointed more toward you, the greater the axis of rotation.
Hope this helps,