A perfect sphere, almost transparent , very transluscent , soundlessly floating above me

I saw and watched an almost transparent perfect sphere floating about 50 /60 feet above me and disappear into the treeline. I estimate the object to be about 18 to 24 inch diameter and moving at a slow walking speed, 2-3 mph It was just a bit higher than the trees. I saw it very clearly and watched it as intensly as one can keeping in mind the fact that I was driving my road home. My best discription that might create an image is "a glass sphere filled with water slowly floating in the sky". It was like you had to see to look at it, It was almost invisible but caused aberation against the skyscape. It made no noticable sound, left no trail. I can see it in my minds eye now as if it had just happened, as well as the exact location of the event. I have told a few folks but never offically reported my sighting.
Date of event is approximate.  PD