ppl. a. (UN-1 8.)
1772. Phil. Trans., LXII. 100. The back-horizon-glass was silvered,… the upper part being left unsilvered.
a. 1853. Pereira, Polarized Light (1854), 113. This combination of Fresnel’s rhomb and an unsilvered glass.
1895. Outing, XXVI. 397/1. The mirror … has a small unsilvered spot in the centre.
