拍品專文
A didactic lens to demonstrate the principle of longitudinal spherical aberration.
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ENGLISH, CIRCA 1860
細節
A 4-inch Crown Glass Bullseye lens
English, circa 1860
the green-tinted planoconvex lens supported in cast iron stand
12½in. (31cm.) high
English, circa 1860
the green-tinted planoconvex lens supported in cast iron stand
12½in. (31cm.) high