Norwegian fishermen were among the first to use glass floats in the 1840s. By the early 1900s fishermen around the world had followed the practice, replacing wood and cork floats with glass ones.
The glass was hand blown from recycled glass, the air sealed with a dab or button of additional glass when removed from the blowpipe. It was then rapidly cooled. The bubbles you see in the glass are a result of this cooling. Later, wooden moulds were used to speed up the manufacturing process. Some floats have a seam which indicate they were made this way in a mould, and not blown.
Fishing lines as long as 50 miles were set in the oceans with such glass floats. Today, glass floats have been replaced with aluminum, plastic and styrofoam. However, old glass floats still swirl in the ocean currents, especially the Pacific Ocean.Storms or certain tidal conditions sometimes break the glass floats loose from this eddy of ocean currents, and they wash ashore.
The glass floats here are those found on the beaches in Oregon. They are most likely Japanese in origin.
Japanese fishermen experimented with spherical floats of several sizes, ranging from 2” to 20”. Some of the floats they made were cylindrical rolling-pin shaped.
As recycled sake bottles were used to make the floats, most are varying shades of green.