both opera glasses are adjustable to the pupil distance. the ones on the right are earlier than the ones on the left.
Date : left about 1880-1900.
right about 1840-1860.
Material used :
left, ivory for eyepieces and objective tubes. Inlay of tortoiseshell in eyepieces.
bridges are made of gilded brass.
Name on the instrument : KIPP en ZN, Holland, retailers.
Right : mother of pearl, guiilded brass.
Note that the brass plates or bridges in this instrument are larger than usual in this sort of instrument.