The two glass you see are beyond rare, more rare than the famous Scottish “Amen” glasses. Made before 1779 for the peace treaty of the Dutch & United States. These have been prove to be made by the hands of the Dutch Royal glass engraver Jacob Sang.
These would have been used to seal the treaty with the United States for the loans granted by the Dutch. Believed to be by the merchants and banks and not the Dutch Crown at this time.
Glass engravers where the most skilled of all engravers and were paid the most for doing this delicate work. The engraver used a cutting wheel and then finished the art with diamond point. Look close at the stripes, look for “Eyes & Faces” like Kill roy and other symbols! Illusion art was common for hundreds of years. Cutting glass like this is many times harder than cutting or engraving metal. There is another glass I did not post, so there are three known to exist. Franklin was well connected to the Dutch with his science and Jacobean support.
American Relic Hysteries 